November 30, 2004
W.H.O. Official Says Deadly Pandemic Is Likely if the Asian Bird Flu Spreads Among People
By KEITH BRADSHER and LAWRENCE K. ALTMAN
HONG KONG, Nov. 29 - A pandemic of human influenza could kill up to 100 million people around the world in a worst case, a World Health Organization official said Monday, significantly raising the agency’s earlier estimates of the potential number of deaths in such a catastrophe.
The W.H.O., a United Nations agency based in Geneva, has been warning about the potential for the A(H5N1) strain of avian influenza virus (known popularly as bird flu) to mutate and cause the next pandemic. The virus has spread widely among bird populations in Southeast Asia.
Dr. Shigeru Omi, the W.H.O.’s regional director for Asia and the Pacific, said that if a pandemic should strike - an outcome he termed “very, very likely” - governments should be prepared to close schools, office buildings and factories to slow the rate of new infections. They also should work out emergency staffing to prevent a breakdown in basic public services like electricity and transportation, he said.
Such arrangements may be needed if the disease infects 25 to 30 percent of the world’s population, Dr. Omi said at a news conference. That is the health agency’s current estimate for what could happen if the disease, now found mainly in birds, developed the ability to spread easily from person to person.
While the agency has previously said that the death toll would be from 2 million to 7 million people, Dr. Omi said the toll “may be more - 20 million or 50 million, or in the worst case, 100” million.
W.H.O. officials in Geneva said later that they had not received an advance copy of Dr. Omi’s remarks and did not know the basis for his estimates and why he believed a pandemic was so likely.
The agency previously has expressed concern that the avian strain has become a more dangerous threat as it has jumped species. But Dr. Omi’s estimates are not based on any new scientific information about the virus’s ability to cause human disease or ways to assess the odds that the virus will become readily transmissible among people.
In sounding the alarm about avian influenza, “W.H.O. is trying to raise concern because we’re concerned, but W.H.O. is not trying to scare the planet,” Dick Thompson, a spokesman for the agency, said in a telephone interview.
“No one knows how many are likely to die in the next human influenza pandemic,” or even when it will occur, said Dr. Klaus Stöhr, the agency’s top influenza expert. “The numbers are all over the place.”
Dr. Malik Peiris, a top influenza researcher at Hong Kong University, said Dr. Omi’s range of possible death tolls was realistic and consistent with research into the A(H5N1) avian influenza virus. “H5N1 in its present form has a pretty lethal effect on humans,” he said.
A few analysts have suggested that the death toll could be considerably higher. Henry L. Niman, a medical researcher in Pittsburgh who is a strong critic of the W.H.O. for being too conservative, said that with more than 70 percent of the human victims of the disease dying so far, the death toll could in theory exceed a billion people if the disease were to spread rapidly, with little if any reduction in current mortality rates.
“That estimate is unscientific, unjustified and an inaccurate extrapolation from the current situation,” Dr. Stöhr said.
No significant quantities of vaccine are likely to be available until five or six months after the virus becomes a pandemic, Dr. Omi said. The virus is constantly evolving, and manufacturers will not want to commit themselves to large-scale production of a vaccine that may prove worthless if the virus evolves further before starting a pandemic, he said.
Keith Bradsher reported from Hong Kong for this article and Lawrence K. Altman from New York.