May 14, 2009 (CIDRAP News) – An international group of experts has examined and rejected the idea proposed recently by an Australian scientist that the novel H1N1 influenza (swine flu) virus is the product of a laboratory accident, the World Health Organization (WHO) reported today.
"The group of scientists feels that this hypothesis does not really stand up to scrutiny, that the evidence suggests that this is a naturally derived virus, and not a laboratory-derived virus," said Dr. Keiji Fukuda, WHO assistant director-general for health security and environment, at a press briefing today.
Adrian Gibbs, 75, a veteran flu researcher, said recently that he had concluded from his analysis of the virus's genetic sequence that it might have evolved in eggs used by scientists to grow viruses and by drug companies to make flu vaccines. Gibbs said he intended to publish a scientific paper describing his hypothesis, according to a May 13 Bloomberg News report.
Fukuda said Gibbs contacted the WHO May 9 to communicate his idea, which he had arrived at by studying genetic data deposited in public databases, not from studying the virus directly.
"Because of the nature of the hypothesis and the credible nature of the scientist, we took this seriously," Fukuda said. The Bloomberg story said Gibbs was involved in research that led to the development of oseltamivir (Tamiflu).
After hearing Gibbs' idea, the WHO asked five of its collaborating centers to evaluate it, Fukuda said. A day later the agency asked the United Nations Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE) to do the same. WHO officials discussed the hypothesis with a large group of experts in both human and animal influenza 2 days ago, he said. They concluded that Gibb's proposition didn't fit the evidence.
Fukuda added that the WHO will need to review Gibbs's research article when it is published, but he indicated that it is unlikely to change the experts' conclusions.
He cited the episode as a positive example of rapid, open scientific communication and debate on medical issues, facilitated by putting genetic data in public repositories.
"We live in an age when it's really not possible to hide things," he said. "It's all for the better as far as I'm concerned. Maybe it means a little more work, but you can also address it in a way which is convincing to people."
"This is much better than dealing with rumors in which the basis for the rumor is not clear and then dealing with answers in which the basis of the answer is not clear," he added.
In response to a question, Fukuda said Gibbs suggested that the novel virus seems to have an increase in lysine (an amino acid) residues and that it sits out on a "long branch" of the influenza phylogenetic tree in comparison with other swine flu viruses. He said it is known that growing flu viruses in eggs can lead to an increase in lysine residues.
However, human, avian, and swine flu viruses differ somewhat in this respect, Fukuda said, adding, "After discussion and looking at older swine influenza viruses, it was concluded that the amount of lysine being seen was in fact very consistent with the natural increase in lysine being seen in swine flu viruses."
Also, the experts who evaluated the hypothesis said that because of historical gaps in swine flu genetic data, many swine flu viruses are somewhat isolated on the phylogenetic tree, so Gibbs' observation on this point was nothing unusual, according to Fukuda.
In other comments at today's briefing, WHO spokesman Gregory Hartl announced that the agency's daily briefings would be suspended for about a week because of upcoming WHO meetings.
A WHO-hosted intergovernmental meeting on virus sharing will begin tomorrow, Hartl said. That will be followed by the World Health Assembly, the annual meeting of WHO member countries, which runs all of next week.
The intergovernmental meeting will deal with the sharing of viral isolates and access to vaccines and other products derived from them, an issue pursued by Indonesia in relation to H5N1 avian flu in recent years.
In other comments at today's briefing:
- Fukuda said experts who met today to discuss whether to recommend mass production of a vaccine for the novel H1N1 virus will probably need to meet several more times before they can come to a conclusion.
- He said the WHO has not seen any evidence that the novel virus is resistant to the antiviral drugs in use (oseltamivir and zanamivir), and the agency is not making any changes in its recommendations on antiviral use.
- The WHO continues to be concerned about the fact that most of the people infected with the H1N1 virus have been young, he said. About half of those who died were healthy and had no predisposing conditions. "It's highly unusual for young, healthy people to die from influenza," he said. "So this is a pattern which is different than what we see with normal influenza," though it has been seen in previous pandemics.