Canada: FluWatch Week 52

Map of overall Influenza activity level by province and territory, Canada, Week 5

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Like the United States, Canada is reporting increasing levels of influenza across much of their nation, prompting recent headlines such as:

Flu outbreak crowding Canadian emergency rooms

Flu season hitting British Columbians earlier

 

Flu blamed for spike in Calgary emergency room visits

Flu cases nearly triple in Windsor

Flu prompts visitor restrictions at St. John's nursing home

The latest FluWatch report from PHAC combines data from weeks 51 & 52.

Overall Influenza Summary

• Influenza activity in Canada continues to rise with increases in all indicators in weeks 51 and 52
• A total of 4632 laboratory detections of influenza were reported, of which 97.7% were for influenza A viruses, predominantly A(H3N2)
• 127 new influenza outbreaks were reported, 87 of which were in long-term care facilities
• 114 new paediatric influenza-associated hospitalizations were reported through the IMPACT network, and 176 hospitalizations including 15 deaths among adults ≥20 years of age were reported through Aggregate surveillance
• The ILI consultation rate increased, but remains within the expected range for this time of year.
• Similar to previous years, older adults (persons aged ≥65 years) are the most affected this season; with 41.3% of laboratory detections to date, increased outbreaks in long-term care facilities, higher hospitalization rates and a high proportion of antiviral prescriptions among those  ≥75 years.

 

As the following chart indicates, influenza detections are on the ascendant, and to a lesser extent, so are RSV (Respiratory Syncytial Virus) cases. Rhinovirus, coronavirus, parainfluenza, and metapneumovirus detections – in contrast -  are on the decline.

 

 

A breakdown of influenza strains identified this year suggest that most are similar to the strains included in this year’s vaccine. That said, we won’t really know how effective this year’s vaccine has been until after the season is over.

 

Influenza strain characterizations

During the 2012-13 season, the National Microbiology Laboratory (NML) has antigenically characterized 177 influenza viruses [136 A(H3N2), 17 A(H1N1)pdm09 , and 24 influenza B].

 

The 136 influenza A(H3N2) viruses were antigenically similar to the vaccine strain A/Victoria/361/2011.

 

The 17 A(H1N1)pdm09  viruses were antigenically similar to the vaccine strain A/California/07/09. Among the influenza B viruses, 20 were antigenically similar to the vaccine strain B/Wisconsin/01/2010 (Yamagata lineage) and four were similar to B/Brisbane/60/2008 (Victoria lineage; component of the 2011-2012 seasonal influenza vaccine) (Figure 6).

Figure 6. Influenza strain characterizations, Canada, 2012-2013, N = 177

 

Note:The recommended components for the 2012-2013 Northern Hemisphere influenza vaccine include: an A/Victoria/361/2011 (H3N2)-like virus; an A/California/7/2009 (H1N1)pdm09-like virus; and a B/Wisconsin/1/2010-like virus.

 

 

For more detailed information on the flu, and what Canadians can do to protect themselves, Public Health Canada maintains a specialized influenza website called  FightFlu.ca.

 

»» Read More

CDC Statement On This Year’s Flu Activity

Photo Credit – Wikipedia

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Later today we should get the the latest CDC  FluView and Canada’s FluWatch surveillance data, but for now we have the following statement by the CDC on this year’s early flu season, which includes advice on vaccination and the use of antivirals. 

 

 

 

 

Flu Activity Picks Up Nationwide

CDC recommends vaccination and antiviral treatment against influenza

January 4, 2013 -- Influenza activity continues to increase in the United States and most of the country is now experiencing high levels of influenza-like-illness (ILI), according to CDC’s latest FluView report. “Reports of influenza-like-illness (ILI) are nearing what have been peak levels during moderately severe seasons,” according to Dr. Joe Bresee. CDC continues to recommend influenza vaccination and antiviral treatment when appropriate at this time.

 

“While we can’t say for certain how severe this season will be, we can say that a lot of people are getting sick with influenza and we are getting reports of severe illness and hospitalizations,” says Bresee, who is Chief of the Epidemiology and Prevention Branch in CDC’s Influenza Division.

 

“Anyone who has not already been vaccinated should do so now,” Bresee says. “And it’s important to remember that people who have severe influenza illness, or who are at high risk of serious influenza-related complications, should get treated with influenza antiviral medications if they get flu symptoms regardless of whether or not they got vaccinated. Also, you don’t need to wait for a positive laboratory test to start taking antivirals.”

 

CDC tracks influenza activity year-round and publishes a report weekly on Fridays. According to this surveillance, the proportion of people seeing their health care provider for ILI in the United States has been elevated for four consecutive weeks, climbing sharply from 2.8% to 5.6% during that time. Last season, which was relatively mild, ILI peaked at 2.2 percent. Comparatively, during 1998-1999 and 2003-2004, which were moderately severe seasons, ILI peaked at 7.6%. During 2007-2008, another moderately severe season, ILI peaked at 6.0%. During the 2009 H1N1 pandemic, ILI peaked at 7.7%.

 

While the timing of influenza seasons also is impossible to predict, based on past experience it’s likely that flu activity will continue for some time. During the past 10 influenza seasons, ILI remained at or above baseline for an average of 12 consecutive weeks, with a range of 1 week (2011-2012 season) to 16 weeks (2005-2006 season). During the pandemic, the proportion of visits to doctors for ILI remained above the national baseline for 19 consecutive weeks.

 

Twenty-nine states and New York City are now reporting high levels of influenza-like-illness and another 9 states are reporting moderate levels of ILI. Ten states are still reporting low or minimal ILI. (These are California, Connecticut, Hawaii, Kentucky, Maine, Montana, Nevada, New Hampshire, South Dakota and Wisconsin). The District of Columbia and 2 states did not have enough information to calculate an activity level.

 

Information about flu-related hospitalizations is collected from 15 states to calculate a rate of laboratory-confirmed influenza-associated hospitalizations. Right now, cumulative influenza hospitalization rates are 8.1 per 100,000 people. According to Bresee, “This is high for this time of year.”

 

Influenza-associated pediatric deaths have been reportable to CDC since the 2004-2005 season. To date, CDC has received reports of 18 pediatric deaths this season. More information about reported pediatric deaths is available at the Influenza-Associated Pediatric Mortality web application.

One factor that may indicate increased severity this season is that the predominant circulating type of influenza virus is influenza A (H3N2) viruses, which account for about 76 percent of the viruses reported. Bresee explains “typically ‘H3N2 seasons’ have been more severe, with higher numbers of hospitalizations and deaths, but we will have to see how the season plays out.”

 

So far this season, most (91%) of the influenza viruses that have been analyzed at CDC are like the viruses included in the 2012-2013 influenza vaccine. The match between the vaccine virus and circulating viruses is one factor that impacts how well the vaccine works. But Bresee cautions that other factors are involved.

 

“While influenza vaccination offers the best protection we have against influenza, it's still possible that some people may become ill despite being vaccinated,” says Bresee. “Health care providers and the public should remember that influenza antiviral medications are a second line of defense against influenza.” (For more information about why people may become sick with influenza after vaccination, see 2012-2013 season Questions and Answers.)

 

CDC has recommendations on the use of antiviral medications (sold commercially as “Tamiflu®” and “Relenza®”) to treat influenza illness. Antiviral treatment, started as early as possible after becoming ill, is recommended for any patients with confirmed or suspected influenza who are hospitalized, seriously ill, or ill and at high risk of serious influenza-related complications, including young children, people 65 and older, people with certain underlying medical conditions and pregnant women. Treatment should begin as soon as influenza is suspected, regardless of vaccination status or rapid test results and should not be delayed for confirmatory testing.

 

To estimate how well influenza vaccines work each year, CDC has been working with researchers at universities and hospitals since the 2003-2004 influenza season conducting studies using laboratory-confirmed influenza as the outcome. Interim VE estimates will be published as soon as they are available. Bresee concludes, “These estimates will provide more information about how well this season’s vaccine is working.”

 

»» Read More

FluView Week 49

 

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Given the reports we’ve seen since the Thanksgiving holidays, it’s no surprise that this week’s CDC FluView  report shows another rise in influenza activity around the nation.

 

The most widespread activity remains in the southern tier of states.

We also learn in this update of another variant flu infection, this time from Minnesota.  

 

 

2012-2013 Influenza Season Week 49 ending December 8, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 49 (December 2-8), influenza activity increased in the U.S.

• Viral Surveillance: Of 7,663 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories during week 49, 2,172 (28.3%) were positive for influenza.
• Novel Influenza A Virus: One human infection with a novel influenza A virus was reported.
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
• Influenza-Associated Pediatric Deaths: One influenza-associated pediatric death was reported and was associated with an influenza B virus.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 2.8%, which is above the national baseline of 2.2%. Seven of ten regions reported ILI above region-specific baseline levels. Eight states experienced high ILI activity, 2 states experienced moderate ILI activity; New York City and 9 states experienced low ILI activity; 31 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in 18 states was reported as widespread; 17 states reported regional activity; the District of Columbia and 11 states reported local activity; Guam and 4 states reported sporadic activity, and Puerto Rico and the U.S. Virgin Islands did not report.

 

More than 28% of samples tested this past week were positive for influenza, with H3N2 leading the way. Here are the details on the novel flu infection.

 

Novel Influenza A Virus:

One infection with an influenza A (H3N2) variant virus (H3N2v) was reported to CDC during week 49 by Minnesota. Close contact between the case patient and swine in the week preceding illness was reported. The patient has fully recovered and no further cases have been identified in contacts of the case patient. This is the second H3N2v infection reported for the 2012-13 influenza season, which began on September 30, 2012.

 

A total of 312 infections with variant influenza viruses (308 H3N2v viruses, 3 H1N2v viruses, and 1 H1N1v virus) have been reported from 11 states since July 2012. More information about H3N2v infections can be found at http://www.cdc.gov/flu/swineflu/h3n2v-outbreak.htm.

 

While it is obvious that flu season has started early this year, it is too soon to know how severe – or prolonged – this season will turn out to be.

The CDC would like you to know, however, that it isn’t too late to get a flu shot, as the peak of influenza activity often doesn’t occur until February or March.

»» Read More

Early Flu Cases Begin To Emerge

 

Photo Credit CDC Influenza Home Care Guide

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While it may not tell us a lot about how the rest of the 2012-2013 flu season will go, over the past couple of weeks several states have begun reporting spikes in early influenza activity.  The last FluView report from the CDC (Nov 17th) indicated flu activity was increasing in parts of the country; notably in the south central and southeastern states.

 

Likewise, the Flu Near You weekly online survey (of self reported symptoms) shows the greatest rate of ILI (Influenza-like-Illness) activity currently in the middle southern states.

 

Flu Near You map  11/29/12

 

NOTE: ILI’s can include many non-influenza viral illnesses, including adenovirus, parainfluenza, rhinovirus and others which are indistinguishable from influenza without laboratory tests (see Dozens Of Ways To Spell `I-L-I’).

 

Although `flu season’ can begin as early as October some years, it is generally December before the virus really begins to make its presence widely known. The Thanksgiving holiday, which often brings many family members together, may play a part in kick starting the epidemic each year.

 

Yesterday South Carolina’s Department of Health and Environmental Control issued the following notice, which included word of a pediatric flu fatality.

 

FOR IMMEDIATE RELEASE
Nov. 28, 2012

Flu cases spiking early, first flu death in South Carolina

COLUMBIA, S.C. – The S.C. Department of Health and Environmental Control notes the state’s first flu-associated death of the season, as well as a significant and earlier-than-normal increase in influenza activity, the agency announced today.

 

“Tragically, a child from Barnwell County has become our first confirmed influenza-associated death of the season,” said Linda Bell, M.D. and interim state epidemiologist. “The flu can be especially serious for the very young and the elderly.

 

“Our latest statewide activity report indicates that influenza has quickly reached ‘widespread’ levels in South Carolina,” Dr. Bell said. “Flu activity typically peaks in February, and it is very unusual for us to see this number of cases so early in the season. Therefore, we strongly encourage vaccination to prevent the flu and its potentially serious consequences.”

(Continue . . .)

 

Similarly, reports from Central Florida indicate an early start here as well.  This from the Orlando Sentinel.

 

Flu season hitting earlier, local clinics say

1:09 p.m. EST, November 27, 2012|By Marni Jameson, Orlando Sentinel

Flu season has arrived in Central Florida, and it's well ahead of schedule, according to Dr. Tim Hendrix, medical director for CentraCare, which operates 21 clinics throughout Central Florida.

 

The CentraCare clinics saw 250 confirmed cases of the flu last week alone. That's more than a 10-fold increase in flu cases compared to Thanksgiving week last year, when the clinics reported 21 confirmed cases, said Hendrix.

(Continue . . .)

 

Other states now confirming flu activity include Arizona, Missouri, Colorado, Maine, New York and Ohio. Most surveillance reports are trailing indicators – showing us the level of activity 1 to  2 weeks ago – so the level of activity today could be different.

 

In any event, if you haven’t gotten your flu shot, now would be an excellent time to do so, as it takes a couple of weeks to begin building antibodies once you get the shot.

 

No, it won’t protect you against non-influenza viral illnesses, and the protection it provides against the flu can vary from year-to-year and person-to-person. 

 

A meta-analysis by CIDRAP in 2011 (see A Comprehensive Flu Vaccine Effectiveness Meta-Analysis) found the trivalent inactivated vaccine (TIV) had a combined efficacy of 59% among healthy adults (aged 18–65 years).

 

Still, flu shots have an excellent safety profile and remain one of the most effective preventatives against catching influenza. Beyond that, being vigilant (read: obsessive) regarding day-to-day flu hygiene is your best safeguard.

 

The CDC recommends:

 

 

Take everyday preventive actions to stop the spread of germs.

• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
• Wash your hands often with soap and water. If soap and water are not available, use an alcohol-based hand rub.
• Avoid touching your eyes, nose and mouth. Germs spread this way.
• Try to avoid close contact with sick people.
• If you are sick with flu-like illness, CDC recommends that you stay home for at least 24 hours after your fever is gone except to get medical care or for other necessities. (Your fever should be gone without the use of a fever-reducing medicine.)
• While sick, limit contact with others as much as possible to keep from infecting them.
• See Everyday Preventive Actions  [257 KB, 2 pages] and Nonpharmaceutical Interventions (NPIs) for more information about actions, apart from getting vaccinated and taking medicine, that people and communities can take to help slow the spread of illnesses like influenza (flu).

 

Of course, if all of these preventatives fail, stay home so you don’t share your virus with the world. If you are at high risk of complications, contact your doctor to see about taking antiviral medications.

Otherwise, CDC’s Influenza Home Care Guide should see you through.

»» Read More

Global Flu Surveillance Updates

 

 

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After an uncommonly subdued 2011-2012 influenza season (see CDC: The Close Of A Mild Season), and a summer that featured an unprecedented number of variant swine flu infections (see An Increasingly Complex Flu Field) in the United States, no one is quite sure what to expect with the coming flu season.

 

Invariably, the word most often used by researchers when describing influenza is `unpredictable’.

 

Nevertheless, in order to come up with a vaccine each year, scientists must decide – 6 months in advance – what flu strains they think will be most active in the season ahead.

 

After 3 years with essentially no changes, this year’s flu vaccine formulation makes alterations to both the H3N2 and B virus strains.

 

• The H1N1 component remains essentially unchanged, with the A/California/7/2009 (H1N1)pdm09-like  still recommended.
• The old A/Perth/16/2009 (H3N2)-like virus now gives way to the A/Victoria/361/2011 (H3N2)-like virus.
• And the Victoria lineage B/Brisbane/60/2008-like virus will be replaced by a Yamagata strain; the B/Wisconsin/1/2010-like virus. 

 

The addition of these two new strains makes getting the vaccine this year all the more important, as community immunity to these recently emerging strains is likely low.

 

The vaccine die having been cast, each fall we monitor influenza activity around the world via a number of reporting tools, including:

 

• The World Health Organization’s bi-weekly global influenza update based on `data sources, including FluNet (reported by the Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States.’
• The WHO/Europe influenza surveillance reports, which are released on a weekly basis. 
• The ECDC provides both their Weekly Influenza Surveillance Overview (WISO) along with their periodic, highly detailed Influenza virus characterisation reports
• Canada releases a weekly FluWatch report.
• And the CDC produces a detailed FluView report each week.

 

There others, of course.

 

Hong Kong’s CHP  produces an excellent Weekly Flu Express, and when it’s summer in the Northern Hemisphere we keep a close watch on the Australian  and New Zealand influenza surveillance sites.

 

Combined, these resources provide us with a pretty good - albeit `backwards looking’ - overview of flu activity. At least in North America, Europe, and parts of the Pacific Rim.

 

Note: There are plenty of areas around the world where surveillance and reporting are lacking, and so we still run the risk of being blindsided by an emerging influenza strain. 

 

During flu season I try to provide links, and highlights, to many of these flu surveillance reports each week. For now, flu activity around the world is low, but there are signs it may be increasing. 

 

From yesterday’s WHO Flu report:

 

Summary

• Many countries of the Northern Hemisphere temperate region reported increasing detections of influenza viruses, particularly in North America and Western Europe, however none have crossed their seasonal threshold for ILI/ARI consultation rates.
• Several countries in the tropical areas experienced active transmission of influenza virus in recent weeks. In the Americas, Nicaragua and Costa Rica reported mainly influenza B virus detections. In Asia, India, Sri Lanka, Nepal, and Cambodia are all reporting a mixture of all three virus subtypes.
• In Sub-Saharan Africa, Cameroon and Ethiopia have reported an increase in influenza virus detections.
• Influenza activity in the temperate countries of the Southern Hemisphere is at inter-seasonal levels. A review of the 2012 southern hemisphere influenza season was published in the Weekly Epidemiological Record (WER) 2 November 2012, vol. 87, 44 (pp. 421–436)

 

The ECDC’s latest WISO Report finds very little flu activity across Europe.

 

Weekly reporting on influenza surveillance for the 2012–13 season started in week 40/2012 in Europe.

•  In week 44/2012, all 26 reporting countries experienced low intensity of clinical influenza activity.
•  Of 279 sentinel specimens tested across 19 countries, only two were positive for influenza virus.
•  No hospitalised laboratory-confirmed influenza cases were reported.

Five weeks into the surveillance season for influenza, there has been no evidence of sustained influenza virus transmission in EU/EEA countries.

 

The story is pretty much the same in Canada, as we learn from their latest FluWatch Report.

 

Overall Influenza Summary

• Influenza activity in Canada increased slightly compared to the previous week; however overall activity still remains fairly low, with most regions of the country reporting no activity.
• In week 44, a total of 64 laboratory detections of influenza were reported; of which 91% were for influenza A viruses [71% A(H3) and 29% A(un-subtyped)].
• Six influenza outbreaks in long-term care facilities were reported in week 44.
• Eleven influenza A-associated hospitalizations were reported in week 44: 8 in adults >20 years of age, and 2 in children.
• The ILI consultation rate increased in week 44 to 21.9 per 1,000 patient visits but is within the expected level for this time of year.

 

In the United States, the CDC’s FluView Reports the beginnings of limited flu activity around the country:

012-2013 Influenza Season Week 44 ending November 3, 2012

 

 

Synopsis:

During week 44 (October 28-November 3, 2012), influenza activity increased in some areas, but overall was similar to activity last week in the United States.

• Viral Surveillance: Of 3,277 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories during week 44, 227 (6.9%) were positive for influenza.
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was slightly above the epidemic threshold.
• Influenza-associated Pediatric Deaths: No influenza-associated pediatric deaths were reported.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.3%, which is below the national baseline of 2.2%. All 10 regions reported ILI below region-specific baseline levels. One state experienced low ILI activity; New York City and 49 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in 1 state was reported as regional; 8 states reported local activity; the District of Columbia and 33 states reported sporadic activity; Guam and 8 states reported no influenza activity, and Puerto Rico and the U.S. Virgin Islands did not report.

 

 

Many years, influenza doesn’t begin to really spread until December or even January, so the level of activity we are seeing today is probably a poor prognosticator of what we will be seeing two or three months from now.

 

Influenza, however, is notoriously unpredictable. Which makes each flu season unique, and worthy of our attention.

 

Stay tuned.

»» Read More

ISDH Statement On H3N2v

 

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My thanks to @Treyfish on FluTrackers for picking up and posting the following announcement from the ISDH (Indiana State Dept. of Health) concerning the cluster of H3N2v swine flu cases in LaPorte County, Indiana I wrote about this morning(see Reports Of H3N2v In Indiana).

 

 

Health Officials are Investigating Flu Illness From LaPorte County Fair

Start Date:  7/25/2012

INDIANAPOLIS—The Indiana State Department of Health, the Indiana Board of Animal Health, and the LaPorte County Health Department are actively investigating an outbreak of four human illnesses associated with the LaPorte County Fair, held July 8-14.  All four individuals had direct contact with swine and all four cases are now recovered.

 

The State Health Department continues to collect information to determine the extent of the illnesses.  Symptoms reported include cough, fever and sore throat.  Confirmed test results on patient specimens indicate the cause as a variant influenza A virus.  Swine specimens also tested positive for this virus.

 

Influenza viruses can be directly transmitted from swine to people and from people to swine.  Human infections are most likely to occur when people are in close proximity to live infected swine, such as in barns and livestock exhibits at fairs.  Influenza viruses are not transmitted by eating pork and pork products.

 

Since 2011, 17 human cases of variant influenza A virus have been identified nationwide.  Six of these cases have been identified in Indiana.

 

Individuals should always wash hands with soap and water before and after petting or touching any animal.  Never eat, drink, or put anything in your mouth in animal areas.  Older adults, pregnant women, young children, and people with weakened immune systems should be extra careful around animals.

 

Hoosiers who have direct, routine contact with swine, such as working in swine barns or showing swine at fairs, and have experienced cough or influenza-like illness should contact their health care provider or local health department.  Symptoms include cough, sore throat, fever, body aches, and possibly other symptoms, such as nausea, vomiting, or diarrhea.

 

While influenza is not an uncommon diagnosis in pigs, the State Board of Animal Health encourages swine owners to contact a veterinarian if their animals show signs consistent with flu, including coughing, respiratory illness, off-feed and fever. Most county fairs have a private veterinary practitioner on call for on-site assistance.

 

Additional information regarding influenza can be found at the Indiana State Department of Health website at www.in.gov/isdh/25462.htm.

»» Read More

The 2012 Flu Season Down Under

The red band signifies the tropics, which has no distinct flu season.  Viruses circulate there, at a low level, year round. – Credit Wikipedia

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While most of the Northern Hemisphere is basking in summer warmth and seeing very little flu activity (Hong Kong being an exception), it is winter south of the equator and flu season is well underway in Australia, New Zealand, and parts of South America and Africa.

 

Watching what happens during the flu season in the opposite hemisphere can sometimes give us clues as to what we might expect in the fall.

 

Of course, it doesn’t always prove predictive. 

 

After the mildest flu season in memory in the Northern Hemisphere, it appears that Australia and New Zealand are getting hit harder, and earlier than usual.

 

First stop, a media report from the West Australian, then we’ll take a look at the latest surveillance data.

 

 

Pressure mounts with different flu virus

Peta Rasdien, The West Australian July 19, 2012, 7:39 am

The earliest start to the flu season in 10 years and the rise of a strain known to cause more severe illness is putting pressure on WA's already stretched health resources.

(Continue . . . )

 

The `different’ flu virus is the seasonal H3N2 virus – which has antigenically drifted slightly away from the vaccine strain currently in use (see WHO: Southern Hemisphere 2012 Flu Vaccine Composition).

 

The existing vaccine contains the A/Perth/16/2009 (H3N2)-like virus, which is hoped to be at least somewhat effective against the evolving virus.

 

This fall, a new vaccine will be introduced that contains the updated A/Victoria/361/2011 (H3N2)-like virus (see WHO: Northern Hemisphere 2012-2013 Flu Vaccine Composition).

 

 

Historically, years where the H3N2 virus has been the dominant strain tend to produce worse flu seasons.  The virus often hits harder than H1N1, and is more likely to target the elderly.

 

From New Zealand’s ESR Public Health Surveillance, we get these latest numbers in their Influenza Weekly Report 2012/28.

 

As you can see, the weekly consultations for ILI’s (Influenza-like Illness) are climbing like a homesick angel, and are running well ahead of the reports from the past 2 years. 

 

While ILI activity in NZ is heavy, it does not reach the epidemic threshold (400 per 100K).

 

The week 28 report summary reads:

 

ILI through sentinel surveillance was reported from 19 out of 20 District Health Boards (DHB) with a national consultation rate of 102.8 per 100 000 (399 ILI consultations). A total of 905 swabs were received from sentinel (79) and non-sentinel (826) surveillance.

 

331 viruses were identified: A(H3N2) (232), A (Not subtyped) (35), A(H1N1)pdm09 (31), B (Lineage not determined) (26), A/Perth/16/2009 (H3N2)-like (5) and B/Wisconsin/1/2010-
like (2)

 

 

About 70% of the viruses identified were H3N2, while only 10% were the 2009 H1N1 strain.

 

The situation in Australia appears similar, although the latest surveillance numbers are not quite as current as what we have from New Zealand.

 

This from Australia’s Department of Health and Ageing.

 

Australian influenza report 2012 - Current report: No 2 - 9 June to 22 June 2012

Summary

• Across all surveillance systems, influenza activity has continued to increase this fortnight.
• All jurisdictions have reported increases in influenza detections above background levels, with South Australia, Victoria, New South Wales, the Australian Capital Territory and the centre of the Northern Territory reporting significant recent increases in activity.
• Influenza-like illness (ILI) activity has continued to increase, with the seasonal increase occurring slightly earlier than in previous years (excluding 2009).
• During this fortnight there were 2,233 laboratory confirmed notifications of influenza, almost double the number of notifications from the previous fortnight. New South Wales, Queensland and South Australia continue to report the highest number of notifications.
• Nationally, influenza A(H3N2) is the predominant circulating strain with some co-circulation of influenza B. Influenza A(H3N2) is predominant across most states and territories, however influenza B represents around 75% and 40% of all notifications in the Northern Territory and Western Australia, respectively. So far in 2012 there have been very few notifications of pandemic (H1N1) 2009.
• As at 22 June 2012, there have been 6,027 confirmed cases of influenza reported. Excluding 2009, notifications of influenza in 2012 have started their seasonal increase slightly earlier in comparison with previous years.
• Influenza associated hospitalisations have continued to increase this fortnight, particularly at the South Australian and Northern Territory sites. Overall, 40% of hospitalisations have been associated with influenza B infections, mostly reported from the Northern Territory. Amongst other jurisdictional sites, influenza A is more common.
• The WHO has reported that the influenza season has not yet started in the temperate countries of the southern hemisphere, although several countries, including Australia, Chile, Paraguay and South Africa have reported small but sustained increases of influenza virus detections. Influenza A(H3N2) viruses have been the most commonly detected in recent weeks in the southern hemisphere temperate region.
• 

Based on this chart, this year’s ILI activity is off to the fastest start in Australia since the H1N1 pandemic of 2009.

As far as what the southern hemisphere’s flu season tells us about the fall flu season ahead?

 

Well, the old adage is that if you’ve seen one flu season, you’ve seen one flu season.

 

Influenza viruses are notoriously unpredictable, and flu seasons that span the globe, even more so.  We won’t know what kind of flu season we are going to have until we’ve had it.

 

We will continue to watch the flu season evolve to our south, however, looking for any clues that might arise.

 

But whatever comes, we do have one advantage over our friends south of the border this year; the new flu shot with antigens expected to be more protective against the drifted H3N2 virus that will be available this fall.

 

Making getting the seasonal flu shot this fall all the more important this year.

 

Add in the routine practicing of good `flu hygiene’ (covering coughs, washing hands, staying home when sick), and you can substantially decrease you odds of getting the flu this coming winter.

»» Read More

Hong Kong’s Extended Flu Season

 

 

 

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As previously mentioned in this blog (see Hong Kong: Flu Activity Continues To Rise), while influenza activity in most the Northern Hemisphere (excluding the tropics) is practically non-existent right now, Hong Kong continues to see an unusual level of flu activity.

 

Today, the Hong Kong government released a brief statement suggesting that a `genetic change’ to the flu virus circulating in Hong Kong may be behind this season’s persistence.

 

While this may sound a bit ominous, there may be less to this story than it first suggests.

 

We’ve been aware of small, antigenic changes occurring in the H3N2 flu virus for a number of months now, a trend which prompted a change to next fall’s flu vaccine (see WHO: Northern Hemisphere 2012-2013 Flu Vaccine Composition).

 

Unfortunately, today’s story provides no real detail on the `genetic changes’ being observed in Hong Kong, making it difficult to draw any comparisons to the antigenic changes seen elsewhere.

 

First the news statement from NEWS.GOV.HK, then I’ll be back with a little more.

 

 

 

Flu season may be longer

June 18, 2012

A genetic change of virus may lengthen this year's peak flu season. Centre for Health Protection Controller Dr Thomas Tsang issued the warning today, saying the flu pattern this year is unusual.

 

Local influenza activity remained high from January to June. From the last week of May to the first week of June there were 1,100 flu cases.

 

The number of influenza detections dropped to about 600 last week, but is still high compared with the average of 100 cases per week in recent years.
He said the flu strain this year has changed slightly in genetic make up.

 

More than 170 people have died of influenza since January, 90% of them being elderly, Dr Tsang said, urging the public and institutions to be alert as the school holidays approach.

 

About 30 enterovirus infections are being reported in childcare centres every week, he added, including seven serious cases.

 

 

Flu viruses are constantly changing and evolving, and so minor changes to the virus are to be expected. Over time enough changes can accrue that they change the behavior or activity of the virus.  

 

Late last month, in a letter to doctors, the Centre For Health Protection mentioned that the seasonal H3N2 virus being seen in Hong Kong had drifted away from the vaccine strain. 

 

An excerpt from that letter reads:

 

The current circulating influenza A(H3N2) virus is antigenically related but not identical to the current vaccine strain, A/Perth/16/2009 (H3N2)-like virus.
Separately, the circulating influenza B viruses belonged to two lineages, the Victoria and Yamagata lineage.

 

The latest laboratory data showed that the Yamagata lineage accounts for around 70-80% of the circulating influenza B viruses. As compared with influenza B viruses of Victoria lineage,  influenza B viruses of the Yamagata lineage are antigenically less similar to the current vaccine strain B/Brisbane/60/2008-like virus. Though the match is less than optimal, studies have demonstrated some degree of cross protection with the available influenza vaccine against current circulating strains.

 

The most recent Flu Express report from the CHP (June 14th) indicates that by far, the bulk of the flu activity being detected right now are seasonal H3.

 

 

While this year’s flu season in Hong Kong remains atypical, the good news is, that there is probably no place on the planet better equipped to analyze changes to the flu virus than Hong Kong.

 

Hopefully we’ll get a more detailed report on what these `genetic changes’ might be in the near future.

»» Read More

WER: Reviewing The 2011-2012 Northern Hemisphere Flu Season

 

 

 

Distribution of 2011-2012  Flu Strains – Source W.E.R.

 

# 6389

 

This week the World Health Organization’s Weekly Epidemiological Record (WER) is devoted to a review of the flu season just completed in the Northern Hemisphere. As you’ll see - while it was unusually mild in the United States - the experiences in other regions of the world varied.

 

 

I’ve excerpted portions of the report below, but you’ll probably want to read the entire article at this link:

 

 

15 June 2012, vol. 87, 24 (pp 233–240)

Contents
232 Review of the 2011–2012 winter influenza season, northern hemisphere

Download full text pdf, 1.76Mb

(Excerpts)

Review of the 2011–2012 winter influenza season, northern hemisphere

This report summarizes the chronology, epidemiology and virology of the winter influenza season in the temperate regions of the northern hemisphere. The review covers influenza activity data collected from October 2011 until the end of April 2012. The data presented have been derived primarily from reports published by national ministries of health or other official bodies reporting on their behalf, or reported to WHO through FluNet and FluID.

 

 

The report describes the mild flu season in the United States:

 

Illness and mortality

In the USA, influenza activity was considerably less in tense than in previous years; clinical consultations for ILI, reported hospitalizations, pneumonia and influenza mortality, and reported influenza-associated paediatric deaths were all lower than in recent years. The percentage of outpatient visits to sentinel physicians for ILI reached the national baseline of 2.4% but never exceeded it, a pattern which has not been observed in at least the last 15 years.

 

Laboratory confirmed influenza associated hospitalizations reported through the Emerging Infections Program, covering 80 counties in 10 of
the 50 states of the USA were lower than the previous year (8.6 per 100 000 population as of 30 April versus 21 per 100 000 population in 2010–2011) and mortality attributed to pneumonia and influenza (P&I) in the 122 Cities Mortality Reporting System slightly exceeded the epidemic threshold (1.645 standard deviations above the weekly mean) only once this season and was below the weekly historical 5-year average for much of the
season.

 

The flu season in Europe was less consistent, with some countries seeing low activity, while others saw an average flu season.

 

Overall, influenza severity indicators were not consistent across Europe. In western Europe, numbers of ILI cases seen in primary care settings were more variable than usual with some countries experiencing relatively few cases scarcely reaching the epidemic baseline (e.g. the United Kingdom and Ireland) while others had more typical seasons (e.g. France and Spain).

 

The number of severe acute respiratory infections reported by 7  participating countries that were positive for influenza was slightly lower than last season (1282 as of 11 May 2012 versus 1548 at the end of the 2010–2011 season). The European Mortality Monitoring Project (EUROMOMO), which pools all-cause mortality data from 15 countries of Europe, reported excess mortality among persons ≥65 years of age in some countries,peaking in February 2012.

This was most notable in countries that experienced more community transmission, around the same time as the peak in influenza transmission. Mortality in the 15 to 64 year old age group was notably lower compared to the 2010–2011 season when A(H1N1)pdm09 was the predominant virus circulating in the area.

 

Meanwhile, Asia saw a very typical flu season, with the exception of Japan, which reported unusually heavy flu activity.

 

Illness and mortality

Reporting rates for ILI visits in northern China, Mongolia and Republic of Korea were all similar to those in previous seasons; however, Japan experienced the highest number of influenza-confirmed cases since 2002, except for the 2009 pandemic period. In Mongolia, the proportion of hospitalizations for pneumonia and the reported number of pneumonia deaths were lower
than during the 2010–2011 season.

 

As is often seen, the influenza strains varied in different regions around the world. While H3N2 virus was the most common strain reported, in Mexico it was the A(H1N1)pdm09 strain that dominated.

 

The season was predominantly associated with A(H3N2) in Europe and North Africa, though influenza B did increase slightly late in the season. Temperate countries of Asia had both influenza B peaks and A(H3N2) peaks, with influenza B appearing first in China and Mongolia followed by A(H3N2) and the reverse sequence in the Republic of Korea and Japan.

 

 

As far as antiviral resistance is concerned, while there were some instances reported, the numbers remain very low.

 

The great majority of the viruses tested this season were sensitive to oseltamivir. However, the late-season appearance of a number of cases with oseltamivir   resistant A(H1N1)pdm09 viruses in Texas, most of which had no direct or indirect exposure to the drug, raises some concern. A cluster of 29 oseltamivir resistant viruses was reported in New South Wales, Australia in the 2011 southern hemisphere winter season but did not result in onward persistence of the resistant virus.

 

And finally, as you’ve probably already heard, a new flu vaccine formulation will be introduced this fall that will include two new flu strains (see WHO: Northern Hemisphere 2012-2013 Flu Vaccine Composition).

 

The rationale for this change (the first in 3 years) is provided in this report:

 

antigenic testing

The seasonal trivalent vaccine for 2011–2012 contained the same 3 viruses as the 2010–2011 northern hemisphere vaccine: A/California/7/2009 (H1N1)-like virus, A/Perth/16/2009 (H3N2)-like virus and B/Brisbane/60/2008-like virus (B Victoria lineage). Early in the season, nearly all of the influenza A viruses detected globally were antigenically similar to the vaccine viruses.

However, increasing antigenic diversity was noted in A(H3N2) viruses in the latter part of the season. These viruses had reduced titre cross-reactivity with antiserum produced against the/Perth/16/2009 virus but higher titres against A/Victoria/361/2011-like reference viruses. In Europe this was associated with lower vaccine effectiveness than in previous seasons in well controlled field observational studies.

Because of antigenic heterogeneity within influenza A(H3N2) viruses irculating during this influenza season, the updated trivalent influenza vaccine for the northern hemisphere will contain an A/Victoria/361/2011-like virus.

 

Influenza B viruses of both the B/Victoria and the  B/Yamagata lineages circulated during this influenza
season in nearly equal proportions in some areas. The increasing proportion of viruses of the  /Yamagata  lineage prompted a change in the next season  vaccine composition to include a Yamagata virus  (B/Wisconsin/1/2010-like virus).

 

 

Now that the flu season in the Northern Hemisphere is essentially over (there are still a couple areas of activity, including Hong Kong and Bermuda), all eyes turn to the southern hemisphere where their flu season is just about to get started.

 

This year’s flu shot for the southern hemisphere is the same as was used in Europe and the Americas last fall, and so we shall be interested to see if the trend in lower vaccine effectiveness reported in Europe persists south of the equator.

 

As far as what this last flu season tells us about the next flu season to come?  Well, the old adage is that if you’ve seen one flu season, you’ve seen one flu season.

 

Influenza viruses are notoriously unpredictable, and flu seasons that span the globe, even more so.  We won’t know what kind of flu season we are going to have until we’ve had it.

 

A good enough reason to get that flu shot every year, and to practice good flu hygiene (covering coughs, washing hands, staying home when sick) all year round.

»» Read More

Northern Hemisphere Flu Activity Declines

 

 

 

# 6322

 

The latest figures from the CDC and the World Health Organization show that the remarkably mild flu season of 2011-12 continues to wind down in most regions of the northern hemisphere. 

 

The virological data also suggests that flu the strains in circulation continue their slow transition away from last year’s vaccine.

 

From the WHO’s most recent Influenza Update we get the following assessment:

 

At the beginning of the influenza season, most viruses tested were antigenically closely related to those found in the current trivalent seasonal vaccine.

 

However, by mid-season, divergence was noted in both the USA and Europe in the A(H3N2) viruses tested and significant numbers of A(H3N2) viruses tested in recent months have shown reduced cross reactivity with the vaccine viruses.

Influenza B virus detections have been both from the Victoria and Yamagata lineages with the former slightly more common in China and parts of
Europe.

 

It is this recent shift in the antigenic properties of the H3N2 virus, and the resurgence of the Yamagata B lineage, that prompted changes to the flu vaccine formula that will be delivered next fall (see WHO: Northern Hemisphere 2012-2013 Flu Vaccine Composition).

 

The WHO also takes note of a small increase in the number of oseltamivir resistant flu viruses detected late in the season.

 

Resistance to neuraminidase inhibitors has been low or undetectable throughout most of the season; however, a slight increase in levels of resistance to oseltamivir has been reported in influenza A(H1N1)pdm09 isolates in the USA. Most (11/16) of these oseltamivir resistant cases have been from the state of Texas, where influenza A(H1N1)pdm09 has been the most common virus circulating.

 

The CDC’s  FluView has additional details on these resistant cases, but first a brief summary of the U.S. flu season moving towards a close.

 

2011-2012 Influenza Season Week 18 ending May 5, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 18 (April 29-May 5, 2012), influenza activity declined nationally and in most regions, but remained elevated in some areas of the United States.

• U.S. Virologic Surveillance: Of the 2,118 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 291 (13.7%) were positive for influenza.
• Pneumonia and Influenza (P&I) Mortality Surveillance: The proportion of deaths attributed to P&I was below the epidemic threshold.
• Influenza-associated Pediatric Mortality: Two influenza-associated pediatric deaths were reported. One was associated with an influenza B virus and 1 was associated with an influenza A virus for which the subtype was not determined.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.4%, which is below the national baseline of 2.4%. All regions reported ILI below region-specific baseline levels. Two states experienced low ILI activity; New York City and 48 states experienced minimal ILI activity, and the District of Columbia had insufficient data to calculate ILI activity.
• Geographic Spread of Influenza: Two states reported widespread geographic activity; 8 states reported regional influenza activity; 12 states reported local activity; the District of Columbia, Puerto Rico, and 28 states reported sporadic activity, and Guam and the U.S. Virgin Islands reported no influenza activity.

So far this season, 16 oseltamivir-resistant 2009 H1N1 viruses have been detected nationally. Three patients were using oseltamivir for 1 day or more at the time of specimen collection. Thirteen had no exposure to oseltamivir; out of those 13 patients, 2 had family members using oseltamivir. (Resistance of influenza A viruses to antiviral drugs can occur spontaneously or emerge during the course of antiviral treatment or antiviral exposure).

 

Eleven of the 16 oseltamivir-resistant viruses were collected from January to April 2012 and are from Texas, where a total of 421 2009 H1N1 specimens have been tested for oseltamivir resistance. Oseltamivir resistance remains quite low nationally and in Texas, even though the percentage of oseltamivir-resistant 2009 H1N1 viruses in Texas (2.6%) is higher than the national percentage. CDC continues to recommend the use of oseltamivir or zanamivir as early as possible for patients with confirmed or suspected influenza who have severe, complicated, or progressive illness; who require hospitalization; or who are at greater risk for influenza-related complications. Use of the adamantanes is not recommended.

 

 

Perhaps the most encouraging of all the flu graphics we’ve seen this year depicts the vast reduction in pediatric flu deaths over this past flu season.  To date, there have been 22 reported pediatric flu fatalities, well under the average.

 

 

 

And finally, a snapshot of influenza-like activity reported nationwide show very little is occurring.

 

 

 

Influenza activity is now expected to pick up in the southern hemisphere, where their flu season peaks normally in June or July.  

 

We’ll be watching activity in Australia, New Zealand, and South Africa with considerable interest over the next few months to see what trends may be developing.

»» Read More

CDC: FluView Week 14

 

# 6282

 

 

The CDC’s latest FluView report (week 14) shows that our below-average flu season in the United States continues to decline, although influenza activity is still described as `widespread’ in ten states.

Today’s FluView also contains official notification of the H3N2v case from Utah, which has been widely reported on this week (see Novel (H3N2v) Flu Detected In Weber County, Utah).

 

First, the notification on the H3N2v case, then few additional excerpts from today’s report:

 

Novel Influenza A Viruses:

One human infection with a novel influenza A virus was detected in a child in Utah. The child was infected with an influenza A (H3N2) variant virus similar to those identified in the 12 human infections that occurred between July and November 2011 in Indiana (2), Pennsylvania (3), Maine (2), Iowa (3) and West Virginia (2). The child has recovered. Contact with swine in the week preceding onset of the child’s illness was reported. State public health and agriculture officials are investigating case contacts and sources of exposure; no additional confirmed cases have been detected at this time. Additional information on these cases can be found in the CDC Flu Spotlight posting.

2011-2012 Influenza Season Week 14 ending April 7, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 14 (April 1-7, 2012), influenza activity was elevated in some areas of the United States, but declined nationally and in most regions.

• U.S. Virologic Surveillance: Of the 3,607 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 756 (21.0%) were positive for influenza.
• Novel influenza A Virus: One human infection with a novel influenza A virus was identified.
• Pneumonia and Influenza (P&I) Mortality Surveillance: The proportion of deaths attributed to P&I was below the epidemic threshold.
• Influenza-associated Pediatric Mortality: No influenza-associated pediatric deaths were reported.
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.5%, which is below the national baseline of 2.4%. Region 10 reported ILI above its region-specific baseline level. One state experienced moderate ILI activity, 1 state experienced low ILI activity; New York City and 48 states experienced minimal ILI activity, and the District of Columbia had insufficient data to calculate ILI activity.
• Geographic Spread of Influenza: Ten states reported widespread geographic activity; 9 states reported regional influenza activity; 20 states reported local activity; the District of Columbia, Puerto Rico, and 11 states reported sporadic activity, and Guam and the U.S. Virgin Islands reported no influenza activity.

Pneumonia and Influenza (P&I) Mortality Surveillance:

During week 14, 7.5% of all deaths reported through the 122-Cities Mortality Reporting System were due to P&I. This percentage was below the epidemic threshold of 7.8% for week 14.

Influenza-Associated Pediatric Mortality:

No influenza-associated pediatric deaths were reported to CDC during week 14. A total of 13 influenza-associated pediatric deaths have been reported during the 2011-2012 season.

 

 

 

While this most recent flu season has happily been one of the lightest in years, the mix of flu viruses circulating today - and their impact - may be different come next fall.

 

And so the old adage applies.

If you’ve seen one flu season . . . you’ve seen one flu season.

»» Read More

CDC: FluView Week 10

 

 

# 6229

 

 

While we’ve suffered no lack of flu-related stories to talk about this year, large numbers of flu cases in the Northern Hemisphere this winter hasn’t been one of them.

 

Flu numbers are still increasing around the United States (According to the WHO they appear to have already peaked southern Europe, North Africa, Japan and the Republic of Korea), but they remain well below seasonal levels.

 

We could still see a late season surge, of course. Flu is nothing if not unpredictable.

 

This week’s FluView provides a stark comparison between this year, and the last two flu seasons.

 

2011-2012 Influenza Season Week 10 ending March 10, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 10 (March 4-10, 2012), influenza activity remained elevated in some areas of the United States, but influenza-like-illness continued to be relatively low nationally.

• U.S. Virologic Surveillance: Of the 4,742 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,099 (23.2%) were positive for influenza.
• Pneumonia and Influenza (P&I) Mortality Surveillance: The proportion of deaths attributed to P&I was below the epidemic threshold.
• 

• Influenza-associated Pediatric Mortality: No influenza-associated pediatric deaths were reported.
• 
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 2.2%, which is below the national baseline of 2.4%. Regions 5, 7, and 10 reported ILI above region-specific baseline levels. Five states experienced high ILI activity; 1 state experienced moderate ILI activity; 11 states experienced low ILI activity; New York City and 33 states experienced minimal ILI activity, and the District of Columbia had insufficient data to calculate ILI activity.
• 

• Geographic Spread of Influenza: Fifteen states reported widespread geographic activity; 22 states reported regional influenza activity; 3 states reported local activity; the District of Columbia, Puerto Rico, and 10 states reported sporadic activity, and Guam and the U.S. Virgin Islands reported no influenza activity.

»» Read More