Thousands of medical laboratories in the US and around the world are racing to destroy a pandemic flu virus, sent to them as part of routine testing kits, in an incident that again underlines the risk of disease from laboratory accidents.
The World Health Organisation said on Wednesday that nearly 3,750 laboratories, all but 75 of which were in the US, had been told to destroy samples of the deadly H2N2 virus received in proficiency testing kits sent out by the College of American Pathologists.
WHO officials said they hoped destruction would be complete by Friday. The virus, which killed between 1m and 4m people in the 1957-58 global flu pandemic, continued to cause annual epidemics until it vanished in 1968. Since people born after 1968 have little or no immunity, any laboratory worker who became ill from the virus could spark a new pandemic that could travel around the world in a few months.
Klaus Stöhr, WHO's influenza co-ordinator, said no H2N2 flu outbreak had been reported since the first batch of testing kits was sent to laboratories in October, and the risk of escape was low. “These are laboratories that know what they are doing,” he said.
Nevertheless, the decision to include H2N2 in proficiency test kits was “short-sighted and certainly unwise”, he said.
Normally, currently circulating influenza viruses are used for proficiency testing, a routine procedure to ensure participating laboratories can identify samples.
Employees at Meridian Bioscience, the Ohio-based company that prepared the samples on behalf of the College of American Pathologists, apparently selected the H2N2 virus without realising the danger.
But Dr Stöhr said the company had not breached any regulations and had acted swiftly to notify laboratories when the problem was revealed on Friday. Nevertheless, the incident has raised unsettling questions about lab handling of flu viruses and other pathogens.
For instance, the alert was given by a Canadian laboratory, which found H2N2 in a sample not related to the testing kit.
The College of American Pathologists is also investigating reports that other companies providing samples for proficiency testing to labs in the US may have included H2N2. WHO says pandemic flu strains such as H2N2 should be given the top biosecurity classification, which would bar their use in proficiency testing. The US Centers for Disease Control are currently reviewing the classification of H2N2 but for the moment the US still gives it a lesser biosafety rating.
The Sunshine Project, a group that monitors biowarfare research, said this latest in a series of laboratory accidents reinforced its call for research on dangerous pathogens to be more tightly restricted.
Other recent incidents have involved the Sars virus and tularemia (“rabbit fever”), a potential biological weapon.
