A national advisory panel urged the federal government yesterday not to inoculate Americans against smallpox, saying the risks associated with the vaccine outweigh the likelihood of a terrorist attack with the deadly virus.
The panel did, however, recommend that vaccinations be offered to select emergency crews designated to respond to bioterrorism events.
The recommendation by the Advisory Committee on Immunization Practices, which helps set national vaccination policy, takes effect only if accepted by Health and Human Services Secretary Tommy G. Thompson.
He promised yesterday to review it as quickly as possible.
The Centers for Disease Control and Prevention in Atlanta and the White House may also weigh in, officials said.
Smallpox hasn't been seen in the United States since 1949 and was officially declared extinct by the World Health Organization after the last case in Somalia in 1977.
However, terrorism experts worry that some countries, notably Iraq, might have secretly kept smallpox virus in the 1970s while claiming to have destroyed it. Experts also fear some of the former Soviet Union's stockpile of weaponized smallpox might not have been destroyed and could end up in terrorists' hands.
The United States stopped vaccinating children against smallpox in 1972. The government now vaccinates only scientists who work with the virus or one of its close relatives, such as monkeypox.
Anthrax changed view
But pressure to re-examine the country's smallpox vaccination policy increased in the wake of last year's anthrax attacks, which raised fears that other, more virulent diseases might be used as terror weapons.
Some scientists and government officials have warned that even Americans inoculated as infants would be vulnerable if an attack occurred, and they have criticized its response plan.
If a smallpox outbreak did occur, the government has advocated a so-called "ring" vaccination strategy - giving shots to people who might come in contact with infected individuals to prevent the disease from spreading.
But some bioterrorism experts have argued that while the ring strategy might work for a natural outbreak, a smallpox attack would likely expose too many people too quickly, overwhelming health care workers.
"As a result, the virus could spread widely and kill thousands before the first vaccinations were given," argued Charles V. Pena, a senior defense policy analyst at the Cato Institute in Washington, in a commentary published last week.
Yesterday, the panel said it would largely stick to its plan - but it did not rule out vaccinating more people if a biological attack warranted it. In the past several months, the U.S. government has stockpiled roughly 100 million doses of vaccine and ordered an additional 200 million shots, which officials say should arrive by the end of the year.
In addition to inoculating scientists who work with smallpox, the panel also recommended that doctors, police officers and others designated by state and local governments to respond to a bioterrist attack be given the chance to be vaccinated. That could result in an extra 20,000 vaccinations, officials said.
One of the biggest factors affecting the panel's decision not to make the vaccine more widely available is the risk of side effects associated with the vaccine, said John F. Modlin of the Dartmouth Medical School, the advisory panel's chairman.
"Unlike all of the other vaccines that we use, this vaccine has special risks," said Julie Gerberding of the CDC. "It is not as safe."
Possible brain damage
The vaccine - which is not made with smallpox but a close relative, the vaccinia virus - can result in side effects ranging from permanent scarring to brain damage. Studies conducted in the 1960s found that as many as three out of every 1 million people died from the vaccine.
Modlin said those numbers would likely be even larger today. People with weakened immune systems from HIV or chemotherapy are especially susceptible to complications from the smallpox vaccine.