Smallpox vaccine has ugly risks

A bioterror threat is weighed against inoculation's side effects.

By Edie Lau -- Bee Science Writer
Published 2:15 a.m. PDT Sunday, November 10, 2002

Most of us over the age of 30 survived it; the proof is in the distinctive scar on the leg, back or, most commonly, upper arm.

Why, then, is the prospect of reviving the smallpox vaccine raising eyebrows?

Dr. Clifford Skinner, a retired pediatrician who once gave the shot routinely and who witnessed some terrible side effects, has a simple answer: "It is kind of a barbaric vaccine," he said.

The shot, which scientists say lasts about 10 years, causes an infection as a means of training the body to ward off the virus that causes smallpox. People with dysfunctional immune systems may be unable to tolerate the infection, and in the past, some were seriously sickened -- on occasion, fatally. Overall, though, the vaccine worked so well that by 1972, routine inoculations ended in America. In 1980, the world was declared free of smallpox.

Today, fearing that stocks of the lethal virus have fallen under the control of terrorists, the United States government is laying plans to vaccinate emergency medical personnel, first-responders, the military and possibly the nation as a whole.

The rub is this: The vaccine is the same one that caused ugly complications in the old days. By one estimate, one out of 18,000 shots elicits a bad reaction.

Furthermore, the vaccine is in one sense less safe than it was 30 years ago because the number of Americans apt to have a bad reaction has grown.

For example, people with a form of eczema called atopic dermatitis have a greater chance of experiencing complications. The condition indicates an imbalance in the skin's immune system. About 15 percent of the population today have the condition -- a rate two to three times that of a generation ago.

That's not counting the people who once had atopic dermatitis but don't anymore. They, too, are prone to complications.

Others who should not have a smallpox shot include anyone with HIV, a disease that was unknown during the smallpox vaccination era; and people taking immunosuppressant drugs to maintain organ transplants or to treat cancer.

Finally, the risk-benefit calculation has changed. When smallpox was a natural threat, the danger of the vaccine was considered minimal compared with the danger of catching the painful, disfiguring and often fatal disease.

Now the likelihood of side effects from the vaccine must be weighed against the likelihood of a bioterror attack -- a probability that's difficult to assess.

Ronald Atlas, president of the American Society for Microbiology and a bioterrorism expert, estimates that 1,000 people would die if the country as a whole were to be inoculated.

Under current circumstances, Atlas said, "I'm not prepared ... to kill 1,000 Americans. (But) I have said that if the CIA has evidence of an imminent threat, you will see me on CNN calling for sacrificing 1,000 Americans."

To complicate matters, the infection caused by the vaccine is contagious. The sore that forms at the site of the shot fills with live viruses. People in the past were known to accidentally spread the infection on their own bodies or to someone else by touching the sore and then touching someone or something else. Or someone else -- especially babies and toddlers -- would touch the sore.

In Atlas' scenario of 1,000 fatalities, 200 of those deaths would occur among people who caught the virus from someone who recently received the shot.

One recent study estimates that as many as 50 percent of Americans would be ill-advised to get the smallpox shot, based on the prevalence of atopic dermatitis alone.

"You can imagine that if 10 to 15 percent of the population has atopic dermatitis, maybe that many again have a history of it, (or) they have a family member who has one or the other of those, you can see those numbers adding up pretty quickly," said Dr. Julie Kenner, a dermatologist and former military researcher who is co-author of the study.

While the national Centers for Disease Control and Prevention works through the issues of vaccine complications -- figuring out, for example, the best ways to screen out people who have ever had atopic dermatitis -- state and local health officials are making general plans for vaccination.

Dr. Richard Burton, associate director of the California Department of Health Services, said individuals such as doctors, nurses and hospital staff who would be in line for the first shots haven't yet been identified.

One thing is certain, he said: The shot will be voluntary.

Dr. Glennah Trochet, Sacramento County public health officer, said that while she knows what categories of people would be vaccinated, it's too early to call for volunteers.

"The folks who take care of patients are clearly the top priority," Trochet said, "Ambulance drivers who respond to calls, people who work in emergency rooms -- not just doctors and nurses, but ancillary help, laboratory folk, etc. ... Now, how many of those folks would be vaccinated depends on how much vaccine we get."

At the Sacramento Fire Department, Assistant Chief Ed Vasques said discussions of the smallpox shot so far have involved senior staff, the Urban Search and Rescue task force and city risk management staff.

For his part, Vasques is prepared to roll up his sleeve and get the vaccine. He looks at it this way: Better to get the shot early and, if complications arise, receive good medical attention, than risk contracting smallpox in a real epidemic when medical services would be strained.

The smallpox vaccine is harsh because it's a relic of a more primitive era in medicine. It was, in fact, the world's first vaccine. In the late 1700s, an English scientist named Edward Jenner, noticing that people who developed a disease called cowpox became immune to smallpox, devised an inoculation using cowpox virus.

Today's vaccine is made of a virus called vaccinia, a germ that isn't found in nature but that evolved in the laboratory out of the cowpox virus. Like cowpox, vaccinia is made of proteins similar to smallpox, which is why immunity to vaccinia offers immunity to smallpox as well.

Pediatricians who practiced 30 or more years ago remember using a special technique to give the shot. Unlike other vaccines, the smallpox inoculation isn't delivered into a muscle, but pressed with a needle resembling a pitchfork into a middle layer of skin.

Into the wound, a bit of vaccinia virus was placed. If the vaccine was effective, a pus-filled sore would grow, a sign that the virus was multiplying as intended. Typically, vaccinees would feel achy and feverish as their immune systems were prodded into action.

It took 12 days or so for the wound to scab over. When the scab fell off, it often left a pox scar that many Americans over the age of 30 can still discern on their upper arms.

Back then, people were casual about the vaccination sore, even while it was contagious. "You'd put a little Band-aid over it and you'd say, 'Don't get it wet. Don't touch it.' That was about it," said Dr. Ernest Petrulio, a retired pediatrician in Sacramento.

For the most part, complications were rare. But Dr. Clifford Skinner, another retired Sacramento pediatrician, was in a position to witness many cases gone awry. His medical training took place in Denver alongside Dr. Henry Kempe, an internationally known infectious diseases expert to whom patients with serious vaccine complications were referred.

"Every now and then the person who has this (shot), they just cannot build up their protection against the vaccine, and it just spreads," Skinner said.

"One of the fads back in the '50s was to do the vaccination on the back over your scapula -- that's the upper part of your back. That makes it more dangerous because it then gives the organism a much bigger area to try to infect," he said. "So literally sometimes, a person may have to have an arm removed or part of their back removed to put a stop to it. It's awful."

Another Sacramento pediatrician, Dr. Gilbert Simon, was growing up in New York City at the time of the country's last smallpox epidemic.

It happened in 1947. A merchant named Eugene Le Bar traveled by bus from Mexico City to New York City. He felt ill by the time he arrived, and after doing a little sightseeing and walking through a large department store, he checked into a hospital.

Five days later, he was dead, and an outbreak had begun.

According to a written account by Dr. Israel Weinstein, then health commissioner of the city, 12 people in all caught smallpox; two died.

Weinstein credited the relatively small number of casualties to a mass vaccination program in which more than 6.3 million people were vaccinated in New York in less than one month.

Simon, then a boy of 10, was one of those people. "We stood in line outside the hospital. People were passing out from the heat," he recalled.

He remembers crying as he got the shot, but the aftermath wasn't too bad. Not for him.

Complications did arise in others. Weinstein wrote that the health department received numerous calls from people fearing they were sickened by the shot.

In the end, he documented three deaths that were genuinely caused by the vaccine -- more deaths than were caused by smallpox itself. The victims were a 66-year-old man who developed septicemia following an infection of the vaccination; and two infants with eczema who were in contact with people who had been recently vaccinated.

"Tragic as these incidents were, it must be borne in mind that had vaccination not been carried out on such a large scale, there very likely would have been thousands of cases and hundreds of deaths," Weinstein wrote.

Beyond complications, the 1947 outbreak demonstrated another truth about the vaccine: It doesn't confer lifelong immunity. Le Bar had been vaccinated as a child, and received a booster -- which evidently didn't "take" -- the year before he left Mexico.

Scientists believe the immunity lasts for about 10 years. A nationwide study is beginning to determine how much immunity, if any, remains in people who had the shot before 1972, and the appropriate dose for booster shots.

Researchers also are trying to develop a safer smallpox vaccine, but that takes time, and it will be a challenge to properly test a new shot, since smallpox no longer exists. The old inoculation, for all its faults, has been proved to work.