- © 2005 Canadian Medical Association or its licensors
The World Health Organization wants 6 billion people around the globe vaccinated in the event of an influenza pandemic — but it will be 6–7 years at best before we have the capacity to do that, says the physician who headed the successful smallpox eradication program.
“At this point in time, we don't have a chance of producing vaccine in the traditional manner and beginning to be able to cope with a global pandemic,” says Dr. D.A. Henderson, a professor of medicine and public health at the University of Pittsburgh. In 1974, Henderson helped start the WHO global vaccination program, and from 1966 to 1977 headed WHO's successful global smallpox eradication campaign.
An influenza pandemic could strike at any time (see previous page), and unless countries adopt and fast-track emerging vaccine technologies, they will run out of time.
Unlike smallpox, where the vaccine composition needed to be altered only every 5–10 years, influenza vaccines must be adapted yearly to the circulating strain. Middle-income and poorer countries do not have the resources to continually adapt and alter vaccine strains, Henderson says.
Countries also need substantial, dedicated manufacturing capacity on standby in order to accelerate vaccine production.
Possible solutions include producing more vaccine quickly with adjuvants that don't require as much antigen, and incubating vaccine in tissue cell culture rather than eggs. Russian researchers, for example, have developed a live vaccine that might be given as a spray or droplets and wouldn't require as much antigen. But these and similar technologies have not been adopted or developed widely.
Finding a modern method of producing vaccine is now a high priority, says Henderson.
Even with adquate supplies, distribution is problematic. Several countries have experience with mass vaccinations. In India, volunteers vaccinated more than 100 million people against polio in November 2004. In 2003, more than 35 countries in Latin America administered 45 million measles vaccinations in a week. But most countries do not yet have that capacity.
“We're looking at [up to] 7 years before you have a really effective solution — and that's being optimistic,” says Henderson.
Countries should prepare by planning to accommodate more patients in hospitals or alternative housing spaces, and stockpiling antibiotics to treat secondary infections, he says.
People have become complacent since the 1918 influenza pandemic, because resulting pandemics in 1957 and 1968 killed much fewer people, Henderson says. “It's hard to crank up.”