How Current Flu Vaccines Affect the Avian Flu

Vaccines are produced each year to prevent seasonal influenza. These vaccines are one of the most effective ways to minimize suffering and death from influenza. However, these vaccines do not protect against the avian flu. Currently there is no vaccine available to protect against the bird flu. Avian influenza, or bird flu, is an infectious disease of birds caused by type a strains of the influenza virus.

Currently there are two drugs commonly used to treat seasonal influenza. These drugs are oseltamivir (commercially known as Tamiflu) and zanamivir (commercially known as Relenza). These drugs are called neuraminidase inhibitors. The efficiency of these drugs depends, among other things, on their early administration (within 48 hours after symptoms begin).

For cases where humans are infected with the bird flu, the drugs may improve prospects of survival, if administered early, but statistics surrounding the validity of that statement are limited. The H5N1 virus is expected to be susceptible to the neuraminidase inhibitors. Antiviral resistance to neuraminidase inhibitors has been studied very little so far but is likely to be detected during widespread use during a pandemic.

There is also research into antiviral medications that can effectively reduce the harshness of an influenza attack. Recent increases in the number and promotion of antiviral drugs for influenza have increased interest in the role of specific antiviral drugs for this condition. However, these antiviral drugs will also not work on avian influenza.

An older class of antiviral drugs, the M2 inhibitors amantadine and rimantadine, could possibly be used against avian influenza, but resistance to these drugs can develop rapidly and this could significantly limit their effectiveness against pandemic influenza. Some strains of the bird flu are already fully resistant to these the M2 inhibitors. However, should a new virus emerge the M2 inhibitors might be effective

Although a vaccine against the H5N1 virus known as the bird flu is under development in several countries, no vaccine is ready for commercial production and no vaccines are expected to be widely available until several months after the start of a pandemic. This means an outbreak would have to already be in progress before a vaccine would be widely available to the public.

Furthermore, the most fatal pneumonia seen in cases of the bird flu has resulted from the effects of the virus, and cannot be treated with antibiotics. Nonetheless, since influenza is often complicated by secondary bacterial infection of the lungs, antibiotics could be life-saving in the case of late-onset pneumonia. Therefore, it is sensible for countries to ensure adequate supplies of antibiotics in advance.

Some clinical trials have already begun to test whether experimental vaccines will be able to fully protect against the virus and to determine whether using different variations of the formula can economize the amount of antigen required, therefore boosting production capacity and making it more affordable to produce. Because the vaccine needs to closely match the pandemic virus, large-scale commercial production will not start until the new virus has emerged and a pandemic has been declared. Current global production capacity falls far short of the demand expected during a pandemic. This means that currently we do not have the resources available to create a vaccine to all who would need it if an outbreak occurred. However, much is being done to hasten the research being done on the bird flu and its possible vaccines.

In February 2006, President Bush approved an extraordinary amount of funds to support vaccine research, development, and procurement. That funding will support research on more resourceful ways to produce vaccine as well as ways to extend a given supply of vaccine to all who need it.