# 2633
Further evidence today - as if we needed any - that if a pandemic should strike in the next few years, our pharmacological options will be limited.
The HHS/CDC have been telling us for two years that our main weapon during a pandemic will be NPI's, or Non-Pharmaceutical Interventions.
But more on that later.
First, we have a new study out of the University of Colorado suggesting that avian flu viruses are becoming increasingly resistant to an older class of antivirals known as the Amantadines.
While not expected to be a first-tier drug against the H5N1 virus, Amantadines have been used in the past in Egypt and Vietnam when Tamiflu resistant viruses have been encountered.
There has been some thought that it could be used as part of an antiviral `cocktail', as well.
So far, 70% of the avian viruses tested remain sensitive to this class of antiviral, but that number appears to be dropping.
Here is the news release from the University of Colorado at Boulder.
Avian Flu Becoming More Resistant to Antiviral Drugs, Says CU-Boulder Study
January 7, 2009
A new University of Colorado at Boulder study shows the resistance of the avian flu virus to a major class of antiviral drugs is increasing through positive evolutionary selection, with researchers documenting the trend in more than 30 percent of the samples tested.
The avian flu, an Influenza A subtype dubbed H5N1, is evolving a resistance to a group of antiviral drugs known as adamantanes, one of two classes of antiviral drugs used to prevent and treat flu symptoms, said CU-Boulder doctoral student Andrew Hill, lead study author. The rise of resistance to adamantanes -- which include the nonprescription drugs amantadine and rimantadane -- appears to be linked to Chinese farmers adding the drugs to chicken feed as a flu preventative, according to a 2008 paper by researchers from China Agricultural University, said Hill.
In contrast, resistance of the avian flu virus to the second, newer class of antiviral drugs that includes oseltamivir -- a prescription drug marketed under the brand name Tamiflu -- is present, but is not yet prevalent or under positive genetic selection, said Hill of CU-Boulder's ecology and evolutionary biology department. The CU findings should help health administrators around the world plan for the possibility of an avian flu pandemic.
The CU-Boulder study is the first to show H5N1 drug resistance to adamantanes arose through novel genetic mutations rather than an exchange of RNA segments within cells, a process known as re-assortment, said Hill. The research on the mutations, combined with molecular evolution tests and a geographic visualization technique using Google Earth, "provides a framework for analysis of globally distributed data to monitor the evolution of drug resistance," said Hill.
The CU-Boulder-led study appears online in the journal Infection, Genetics and Evolution. Co-authors included CU-Boulder Associate Professor Robert Guralnick, recent CU-Boulder graduate Meredith Wilson, Farhat Habib of Kansas State University and Daniel Janies of Ohio State University.
"As these adamantanes have gotten into nonhuman vectors like birds, the positive selection for resistance to avian flu is rising," said Hill. "If Tamiflu is ever used in the manner of adamantanes, we could conceivably see a similar resistance developing through positive selection."
We're told it will take several months for vials of a pandemic-specific vaccine to roll off the assembly lines, and even longer before it can be distributed to the public.
It will likely take two shots . . . a month apart, to confer reasonable immunity.
Figure six months - maybe longer - before the first jabs are available to the general public.
And that assumes everything goes well.
In the meantime, a pandemic virus could mutate, or drift, rendering the vaccine under production less effective.
Antiviral medications will be in short supply, and there are concerns that their effectiveness may wane over time.
Even antibiotics, which won't help with a viral infection but would help with secondary bacterial infections, may be up against an increasing number of resistant pneumonia strains.
Vaccines, antivirals, and antibiotics are valuable adjuncts in a battle against a pandemic, but they are not a panacea.
Maybe someday, but not today.
(CDC's Community Pandemic Guidance)
NPI's, such as social distancing, school closures, hand washing, wearing face masks, and the isolation of the sick are actions that can be taken in every community and require very little specialized training or equipment.
And when layered, NPI's will hopefully prove an effective weapon to slow the spread of a pandemic.
The goal is to `flatten' the curve, to reduce transmission of the virus, so that fewer people become ill at the same time.
This will reduce the burden on the health care system, hopefully limit the effects of absenteeism on the supply chain, and potentially give manufacturers time to develop and dispense vaccines.
The downside, other than the reality that there won't be a magic pill or shot during the first wave of a pandemic, is that community mitigation efforts are likely to make a pandemic wave last longer.
If you haven't downloaded, and read the CDC's planning guidance, now is a good time to do so.
Individuals, families, and business owners will need to take specific steps now, before a pandemic starts, to enable them to follow these guidelines.
Today is a good day to start.
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