Tuesday, April 19, 2005

"More than overdue." What is there to deliberate about?

The errant and "inappropriate" shipment of influenzaA/H2N2 hastily recalled by WHO and CDC over the last week seems mostly accounted for. Mostly. Missing shipments to Lebanon, Mexico and Chile have reportedly been found in a FedEx warehouse, but not all shipments within the US have been located as of this date.

A few questions remain, however. One is the nature of the virus, which has been variously reported as virtually identical to the pandemic virus of 1957-58 (via the reliable Helen Branswell at Canadian Press) or as H2N2/Japan, a vaccine reference strain whose virulence may (or may not be) less than the circulating pandemic virus according to the less reliable Wendy Orent in WaPo). No one knows if the virus is less dangerous than the original nor is it completely clear it is really a "reference strain." Reference strains made in the 1970s and later are reassortants of the HA and NA genes from the circulating virus with influenza A/PR8, a high growth strain used to make vaccines in embryonated eggs. But H2N2/Japan seems to be a strain from the original epidemic that has been passaged frequently in laboratories, and as a result, "may" (or may not) be less virulent.

Another question relates to how a patient's unrelated specimen managed to become contaminated by this virus in an (as yet unidentified) lab in Vancouver. The cross contamination was fortunate, in the sense that the patient's specimen was analyzed more thoroughly than would have been the case for the original proficiency test sample, which only required it be identified as influenza A. But it leaves open the question of how, physically, the contamination occurred. CDC and WHO are busy telling us that accidental infection of a lab worker is very unlikely because they are highly trained and chances of exposure are miniscule. How, then, did the patient's specimen become contaminated?

The third, and perhaps most important question, relates to why H2N2 is handled under biosafety level 2 (BSL 2) conditions in the US ("good laboratory practice") but requires BSL 3 protection in Canada (use of safety cabinets and other protections). CDC Director Gerberding explained that because influenza isn't a bioterrorist agent, it did not receive the proper attention. Besides showing unbelievable stupidity, incompetence and a blind sense of misplaced priorities, we note that despite Canada's pleas and WHO's dismay the US has still not taken the required step of classifying H2N2 as a BSL 3 agent:
The head of the WHO's global influenza program said Wednesday that countries which have not already done so should upgrade the biosafety level applied to the flu strain that laboratories around the world are racing to destroy because of its pandemic potential.

"Now it's more than overdue perhaps to review the situation, the biosafety levels that are being attached to this virus," Dr. Klaus Stohr of the World Health Organization told The Canadian Press in an interview from Geneva.

Dr. Julie Gerberding, director of the U.S. Centers for Disease Control, suggested authorities in the U.S. will speed forward with deliberations over a recommendation that the strain, known as H2N2, be upgraded from a Level 2 biosafety grade to a Level 3, as it is in Canada.

The scientific director of Canada's National Microbiology Laboratory said the U.S. ought to take that step.

"It's clear that this H2N2 virus should be a Level 3 virus to me and I think that's what will happen in the United States," Dr. Frank Plummer said in an interview. (Helen Branswell)
So CDC will speed forward with deliberations. What is there to deliberate about?