Influenza virus (continued)
Lethal human influenza A virus can be generated in the laboratory, utilizing the recently developed reverse genetic system whereby influenza viruses can be generated by transfection of multiple DNAs. Pathogenic H5N1 virus has already been generated using this reverse genetic system.
It can be argued that most terrorists would not have the knowledge, facilities and ingenuity to carry out these recombinant DNA experiments. This is probably the case at the present time, but the situation can be expected to change in the future, perhaps after as little as 5-10 years.
Vaccination will probably be of limited value against an influenza virus bioterrorist attack. Currently it takes about 6 months to prepare a vaccine against a new influenza virus strain.
In addition, the vaccine approach can be readily thwarted by bioterrorists who could spread several influenza viruses with different hemagglutinin (HA) antigenic sites.
In contrast, antiviral drugs that are directed at functions shared by all influenza A virus strains constitute the best line of defense against a bioterrorist attack. Currently the neuraminidase (NA) inhibitors (zanamivir and oseltamivir) are the only such antivirals available. Consequently, it would be prudent to maintain a stockpile of the NA inhibitors while other antiviral drugs are being developed.
Krug, Antiviral Res. 57, 147-150 (2003)