WASHINGTON — Government health officials are mobilizing to launch a swine-flu vaccination campaign this fall that is unprecedented in its scope - and in the potential for complications.
The campaign aims to vaccinate at least half the country's population within months. While more people have been inoculated against diseases such as smallpox and polio over a period of years, the United States has never tried to immunize so many so quickly.
But even as scientists rush to test the vaccine to ensure it is safe and effective, the campaign is lagging. Officials say only about a third as much vaccine as they had been expecting by mid-October is likely to arrive by then, when a new wave of infections could be peaking.
Among the unknowns are how many shots people will need, what the correct dosage should be and how to avoid confusing the public with an overlapping effort to combat the regular seasonal flu.
To prepare, more than 2,800 local health departments have begun recruiting pediatricians, obstetricians, nurses, pharmacists, paramedics and even dentists along with a small army of volunteers from churches and other groups. They are devising strategies to reach children,teenagers, pregnant women and young and middle-aged adults in inner cities, suburban enclaves and the countryside.
"This is potentially the largest mass-vaccination program in human history," said Howard Markel, a professor of medical history at the University of Michigan who is advising the Centers for Disease Control and Prevention as it spearheads the effort.
Public health officials describe the effort as crucial to defend against the second wave of the Northern Hemisphere's first influenza pandemic in 41 years.
As schools reopen, the number of cases could jump sharply within weeks, sparking a second wave potentially far larger than the outbreak last spring. Although the swine flu appears no more dangerous than the typical seasonal flu, the new virus - known as H1N1 - is likely to infect many more people because most have no immunity to it.
The vaccine effort carries political risks for the Obama administration. "If the outbreak fizzles, they will be susceptible to being criticized for spending billions of dollars," said Harvey Fineberg, president of the National Academy of Sciences' Institute of Medicine, which advises Congress about medical issues. "On the other hand, if this outbreak is early and severe and there isn't enough vaccine, they'll be criticized for under preparation."
Officials stress that they are proceeding cautiously. A final decision to move forward will not be made until they get the results of clinical trials - testing for safety and to determine dosing - and assess the virus's threat. But officials are confident the vaccine will pass muster and expect a campaign will be launched as soon as manufacturers deliver the first vials.
"There's little doubt we're going to vaccinate people," said Anthony Fauci of the National Institute of Allergy and Infectious Diseases, who is leading the government's testing of the vaccine. "Who and when and exactly how we have to figure out."
The campaign is haunted by memories of the government's ill-fated 1976 effort to vaccinate against swine flu. The epidemic fizzled, but the vaccine was given to 40 million people and blamed for causing a rare paralyzing disorder known as Guillain-Barre syndrome.
Another wild card will be whether the vaccine will be delivered with an "adjuvant" to boost its effectiveness or stretch limited supplies into more doses. Adjuvants have been used in Europe, but the Food and Drug Administration has not authorized their use in the United States.
"This is an overreaction," said Barbara Loe Fisher of the National Vaccine Information Center, which opposes many vaccine policies. "There is no national security threat here. Why are we operating like this? This is not polio. This is not smallpox."
Fears and misinformation about the vaccine are already circulating, including inaccurate claims that the vaccine will be mandatory.
"I'm very concerned about the dangers of vaccines," said Janice Smith, 58, of Mishawaka, Ind., who attended a public hearing Aug. 15, one of a series of meetings the CDC has sponsored to gauge public sentiment about the vaccine.
Authorities are adamant that vaccination will be voluntary, and say there is no reason to think the vaccine will be any less safe than the usual flu vaccine. An adjuvant will be used only if necessary and proved safe, they say.
To address concerns of pregnant women and parents with young children, some vaccine is being produced without a mercury additive. And because the short-term studies can identify only common, immediate side effects, the CDC will step up monitoring for rarer, serious complications such as Guillain-Barre.
"We're putting into place systems that are as good as we can have to identify problems quickly if they do occur," CDC director Thomas Frieden said.
On Friday, officials reported that no "red flags regarding safety" had emerged in the clinical trials. "We are continuing oversight on the quality and safety of the vaccine being produced, and the production process itself,"said Jesse Goodman of the FDA. "That's going well so far, but our oversight is continuing."
Setting priorities for delivering the vaccines will bring other complications. The elderly, usually first in line for flu shots, will not be this time because they seem more resistant to the swine-flu virus. But they remain a top priority for the seasonal shots.
Schools considering giving shots to children are making plans to get permission from parents and have to determine how best to line up anxious, rambunctious students.
Everyone who gets a swine-flu shot may need a booster several weeks later, potentially causing mix-ups about who got which shot when.
But Frieden and other outside observers expressed confidence that the program would be safe and successful.
The federal government has spent close to $2 billion to buy up to 195 million doses of vaccine and adjuvant, including both the standard shots and the newer FluMist nasal spray vaccine made by MedImmune of Gaithersburg, Md.
The government is prepared to buy enough to vaccinate every person - 600 million doses altogether - if the pandemic or demand warrants it. That could increase the cost to $5 billion for the vaccine alone. It would cost at least $9 billion to administer the vaccine to the entire population, according to the Association of State and Territorial Health Officers.
Although five companies are racing to produce as much vaccine as possible, the first batches are not expected for two months, in part because the virus grew at about half the projected rate. Production appears to be increasing, but the first 45 million to 52 million doses - about a third of what officials were anticipating - won't be ready until mid-October, with about 20 million doses a week expected after that to continue the campaign through the winter.
While the vaccine itself will be free, providers could charge about $15 to administer the vaccine - a fee that will be covered by Medicare and many health insurance plans.
Information for this article was contributed from Washington by Rachel Saslow and from Chicago by Kari Lydersen of The Associated Press.
Front Section, Pages 1, 2 on 08/24/2009