The World Health Organization on Thursday acknowledged what many health experts have been saying for weeks: The outbreak of H1N1 virus is now a pandemic.
“The world is now at the start of the 2009 influenza pandemic,” said Dr. Margaret Chan, director-general of the WHO, at a Geneva teleconference. “This virus is now unstoppable.”
In a letter sent to member countries, Chan said she is officially raising the agency’s infectious-disease alert to Phase 6, its highest level, in recognition of the fact that the virus is now undergoing communitywide transmission in Australia as well as in North America.
Such spread in two distinct regions of the world is the primary criterion for raising the alert level. But the agency also said that the pandemic is only “moderate in severity” and cautioned against overreactions to the increased alert level.
Already treated like pandemic
The announcement marks the advent of the first global influenza epidemic in 41 years. The last one was the Hong Kong flu epidemic of 1968, which killed an estimated 1 million people worldwide.
So far, the H1N1, also called swine flu, pandemic in 2009 has accounted for 28,774 laboratory-confirmed cases and 144 deaths in 74 countries, although health officials believe many times that number have been infected but have not been tested because those people’s illnesses have been mild.
A normal seasonal flu outbreak kills about 250,000 to 500,000 people worldwide.
In most industrialized countries, the rise in the alert level will have little practical effect because health authorities were already behaving as if a pandemic had been declared. In the United States, there have been more than 13,000 cases, more than 1,000 hospitalizations and at least 27 deaths.
“We have been reacting as though it were a pandemic already,” said Dr. Anne Schuchat, director of the Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Disease.
Alert may speed vaccine production
But it will accelerate the production of a vaccine against the new virus. Several nations have signed contracts with manufacturers that call for vaccine production if a pandemic is declared. Most of the manufacturers have received “seed stock viruses” from the CDC in the past two weeks, allowing them to begin the lengthy process of growing the virus in eggs and producing vaccines. But vaccines will not be available until September, at the earliest, and the supply will be limited.
Schuchat cautioned, however, that use of the vaccine is not a foregone conclusion.
“The decision on whether or not to use a vaccine is a separate decision from whether or not to make it,” said Dr. Thomas R. Frieden, who became CDC director Monday.
The WHO had hesitated to raise the alert level out of concern that such an announcement would be misconstrued as an indication that the virus has become more pathogenic.
In fact, all evidence to date is overwhelming that the virus’ effects are mild. Experts fear, however, that as H1N1 passes through populations, it could mutate to become more lethal and return with increased force in the winter influenza season.
“The virus writes the rules, and this one, like all influenza viruses, can change the rules without rhyme or reason at any time,” Chan said.
