Not Exactly A Magic Bullet

 

 


# 2401

 

 

According to the Times of India, it is the Magic Bullet Against Bird Flu.

 

Science Daily's headline reads Bird Flu Vaccine Protects People And Pets  while News-Medical.Net is a bit more restrained; their headline simply reads Universal vaccine could protect people and pets from deadly flu pandemics.  

 

 

All of this hoopla stems from a journal article that appears in the November edition of the Journal of General Virology  entitled:

 

 

An avian live attenuated master backbone for potential use in epidemic and pandemic influenza vaccines

Danielle Hickman{dagger}, Md Jaber Hossain{dagger},{ddagger}, Haichen Song, Yonas Araya, Alicia Solórzano and Daniel R. Perez

Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, 8075 Greenmead Drive, College Park, MD 20742-3711, USA

 

 

The entire article is freely available, but here is the abstract (reparagraphed for readability).

 

The unprecedented emergence in Asia of multiple avian influenza virus (AIV) subtypes with a broad host range poses a major challenge in the design of vaccination strategies that are both effective and available in a timely manner.

 

The present study focused on the protective effects of a genetically modified AIV as a source for the preparation of vaccines for epidemic and pandemic influenza.

 

It has previously been demonstrated that a live attenuated AIV based on the internal backbone of influenza A/Guinea fowl/Hong Kong/WF10/99 (H9N2), called WF10att, is effective at protecting poultry species against low- and high-pathogenicity influenza strains.

 

More importantly, this live attenuated virus provided effective protection when administered in ovo. In order to characterize the WF10att backbone further for use in epidemic and pandemic influenza vaccines, this study evaluated its protective effects in mice.

 

Intranasal inoculation of modified attenuated viruses in mice provided adequate protective immunity against homologous lethal challenges with both the wild-type influenza A/WSN/33 (H1N1) and A/Vietnam/1203/04 (H5N1) viruses.

 

Adequate heterotypic immunity was also observed in mice vaccinated with modified attenuated viruses carrying H7N2 surface proteins. The results presented in this report suggest that the internal genes of a genetically modified AIV confer similar protection in a mouse model and thus could be used as a master donor strain for the generation of live attenuated vaccines for epidemic and pandemic influenza.

 

 

 

A universal flu vaccine, one that would be effective across all strains, has been the holy grail of virologists for many years.  If developed, and widely deployed, it could conceivably stop a pandemic.

 

 

Here scientists have taken the internal genes from the H9N2 avian influenza virus,  a strain known for its wide host range, and have created a genetically modified vaccine.  

 

 

One that, hopefully, would work against a variety of influenza viruses and be effective for a host of species.

 

 

This is how Science Daily explains the research:

 

The researchers found that the central genes or 'backbone' of the H9N2 virus that infects guinea fowl can protect birds and mice against highly pathogenic strains of influenza. They modified the virus to make it less pathogenic and then used it to vaccinate mice.

 

Three weeks after being vaccinated, the mice were infected with the potentially lethal H1N1 virus - the same virus that caused the 1918 Spanish flu pandemic. All the vaccinated mice survived with no signs of disease. Vaccinated mice also survived infection with the deadly H5N1 bird flu virus, again showing no signs of disease.

 

 

Interesting research and possibly another step along the way to a universal influenza vaccine.  

 

But not exactly a `magic bullet'; at least - not yet.

 

And no, it hasn't been tested in people or pets, despite the headlines.  Testing has, however, shown promise in laboratory mice.

 

But we know that what works in mice doesn't always work in humans, and it may take years before we know if this approach is both safe and effective in people.

 

That's the reality here. 

 

And even if you have a `magic bullet', you still need a gun to fire it from.   And that `gun' is a well funded global public health infrastructure, with the ability to deploy a vaccine worldwide.

 

The logistics of vaccinating billions of people is more than just a little daunting.  There are huge political, social, and monetary obstacles as well.

 

So while this is valuable research, and may someday lead to new techniques for vaccine manufacturing, it is a bit early to pop the Champaign corks.

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