H1N1 vaccines should offer broad protection even if the pandemic flu virus mutates as it spreads, a top World Health Organization expert said on Wednesday.
Marie-Paule Kieny, director of the WHO's vaccine research program, said that health workers should get immunized first when the shots begin to be distributed, as early as this month.
"The consensus is that the first doses will be available to governments for use in September," she said. The U.S. Centers for Disease Control and Prevention said last week that it was unlikely the vaccines would be available before October.
About 30 candidate vaccines are being worked on in the rush to combat the flu strain that first emerged in Mexico and the United States and then moved around the world. The WHO declared it a global pandemic in June.
"No countries will have vaccine for everyone from the first day it is available for use," Kieny told the WHO Bulletin, a publication of the United Nations agency.
The pharmaceutical industry will used tiered pricing for the governments buying H1N1 vaccines, charging rich countries $10 to $20 per dose, middle-income countries half that amount and low-income countries half that again, according to Kieny.
"These are ballpark figures but this is the order of magnitude," she said.
Companies making H1N1 flu vaccines include AstraZeneca's MedImmune, CSL, GlaxoSmithKline, Novartis and Sanofi-Aventis. Other flu vaccine makers include Baxter and Solvay.
Kieny said "a complete clinical evaluation" of H1N1 vaccines was not necessary, but trials were needed to know whether one or two doses are necessary, whether some people may be at risk from the shot, and whether it can be delivered in a mixture with other vaccines.
Research on shots developed in response to H5N1 bird flu, which is more fatal than the pandemic variety but spreads much less easily between humans, has helped vaccine manufacturers develop safe H1N1 shots quickly, according to Kieny.
"Based on the extensive knowledge available on seasonal vaccines and the results obtained through evaluation of H5N1 avian influenza vaccines, there is no doubt that it will be possible to make effective H1N1 pandemic vaccines," she said.
U.S. researchers said this week that H1N1 appeared unlikely to mix with other circulating flu viruses into a "superbug." Kieny said the new strain would have to mutate in a significant way for the vaccines in the works to be rendered ineffective.
"Although the virus can mutate, we hope that there will be enough cross-protection through recognition of the new virus. But if the virus changes too much, we will need new vaccines," she told the WHO Bulletin.
Kieny stressed that it was neither possible nor necessary to vaccinate every person against the H1N1 flu, which has killed some pregnant women and people with other diseases such as diabetes but caused manageable flu symptoms in most patients.
"We should not be 'hypnotised' by vaccines," she said.
"There are other measures, such as social distancing, school closure, avoidance of large gatherings, antibiotics and personal hygiene," she said. "This is not like rabies, which is 100 percent fatal. We are talking about a disease from which most people recover very well."
The WHO predicts that a third of the world's population will eventually be infected with H1N1, commonly known as swine flu. So far, at least 2,185 people have died from it and millions of people have been infected.