The Internet can be a significant source of misinformation about vaccines. There are numerous sites that gather scare stories about vaccination based on little more than anecdotal reports from parents, and many chat rooms discussing vaccination in hysterical voices and without benefit of scientific information.
This doesn’t mean that vaccines are without dangers, there are dangers, but the dangers must be understood scientifically, and especially in comparison to the risks involved in getting the diseases these vaccines prevent. When looking at an Internet site, ask yourself some questions:
Who is the owner or sponsor of this site? Does it contain references to scientific articles published in well-known journals? Are the studies it cites anecdotes of individual cases, or are they scientific studies that require large numbers of cases and scientific controls? Is the site endorsed by a university or a professional organization? Which ones? Are the sources of information named, or are assertions attributed to “renowned scientists” or “noted researchers”? Is an assertion too good (“Eating banana peels cures AIDS!”) or too absolutely appalling (“Millions die every week from flu vaccines!”) to be true? Does the site reveal the limitations of its information? In other words, is this junk science or real science?
How can you compare the risk of a vaccine against the risk of getting the disease? Only with statistical information based on large studies. Measles, for example, is a highly contagious disease that leads to pneumonia in 1 of 20 cases, to encephalitis (inflammation of the brain) in 1 in 2,000 cases, and death in 1 in 3,000 cases; mumps causes encephalitis in 1 of 300 victims; rubella infection in pregnant mothers causes birth defects one in every four times.
The only risk from the MMR (measles, mumps, rubella) vaccine, on the other hand, is getting encephalitis or a severe allergic reaction, which happens one time in every 1 million vaccinations. For DTP vaccine (diphtheria, tetanus, and pertussis) the story is much the same: the risk of dying from diphtheria is 1 in 20. The only risk to an infant from the diphtheria vaccine is continuous crying, then full recovery, which happens once in every 100 injections. Tetanus causes death in 3 of 100 of its victims; the tetanus vaccine causes convulsions or shock and then full recovery once in every 1,750 injections. Whooping cough causes 1 death in 200, but no one has ever been proven to have died from a pertussis vaccination.
Vaccination rates in the United States are very high. Because states require immunizations before kids are allowed to enroll in school, about 95 percent of kids are protected against vaccine-preventable diseases by the time they are six years old. The CDC does not, however, collect data on whether the vaccinations were given at the appropriate times.
What about the 5 percent of children who don’t get vaccinated? They get sick at higher rates, and they make other kids sick, even ones who have been vaccinated. About half of all states allow exemptions from vaccination for religious, medical, or philosophical reasons. Colorado is one of them, and in 1998, 2 percent of Colorado kids were given exemptions. The CDC studied the results, analyzing data collected between 1987 and 1998. The risk of measles among the unvaccinated was 22.2 times as high, and the risk of whooping cough was 5.9 times as high. Moreover, in counties with the highest rates of exemptions, the measles rate was 50 percent higher among vaccinated kids than in the rest of the state. Clearly, failing to vaccinate a small number of children puts a large majority at risk for illness.
All the recommended vaccines have proven safe and effective over many years of use. But sometimes a vaccine doesn’t do what it’s supposed to do. Such was the case with the vaccine for rotavirus.
By the time they are five years old, almost all children, in industrialized countries and elsewhere, have had the illness caused by this virus. Most recover without aftereffects. But it causes diarrhea, which in severe cases can be fatal. It kills approximately 40 children a year in the United States and hundreds of thousands worldwide.
Rotavirus is the most common cause of severe gastroenteritis in infants and young children in the United States, and is a common cause of emergency room visits, outpatient clinic visits, and hospitalization, 55,000 kids a year are hospitalized with it. Rotavirus diarrhea costs $264 million a year in direct medical costs, and more than $1 billion in societal costs attributable mainly to loss of work time among parents and caregivers. An affordable vaccine to prevent the disease is obviously a desirable alternative, and several rotavirus vaccines have been developed. One of these, an oral, live, rhesus-based preparation manufactured by Wyeth Laboratories, was approved for use by the Advisory Committee on Immunization Practices (ACIP) of the CDC in March 1999.
Approval of the vaccine came only after extensive studies of its safety and effectiveness. In the notification recommending the use of the vaccine and specifying the dosages and their timing, the CDC made note of several side effects, but none were deemed sufficiently serious to reject use of the vaccine.
Among these side effects was a condition called intussusception, in which one part of the intestine becomes twisted and pushed into an adjoining segment, causing bowel obstruction and acute abdominal symptoms. Whether they have had the vaccine or not, the condition is seen most commonly in children. The researchers noted 5 cases of intussusception in 10,054 recipients of the vaccine, and 1 case in 4,633 children who had received placebos. This is not a statistically significant difference, that is, it is not enough to conclude that the vaccine is the cause of intussusception.
The CDC did, however, warn that although the connection did not seem to be causal, it was nevertheless something that would have to be looked for during postlicensure surveillance. It is during this final period of examination of a drug, when very large numbers of people are using it, that apparently rare side effects can be shown to be more common than clinical trials of the medicine revealed. This is exactly what happened in the case of Rotashield, the brand name given by Wyeth to its rhesus rotavirus vaccine.
By July 1999, the CDC had suspended the use of the vaccine to review data indicating a strong association between its use and the occurrence of intussusception. This review confirmed the association, and the vaccine was withdrawn from the market in October. This led some people to believe that the CDC and the ACIP must have made some kind of mistake. But they had not. In fact, the procedure worked exactly as it is designed to work with any new drug.
There is currently no vaccine to prevent rotavirus infection, and if you have an infant you can be almost certain that at some time he or she will be a victim of the disease. Rotavirus, as its name suggests (Latin rota = wheel), looks like a wheel under an electron microscope.
The disease is highly contagious, and a child may be contagious before the diarrhea begins and for a few days after it ends. It is usually transmitted by the fecal-oral route, but unlike most viruses it is fairly stable on environmental surfaces and can be transmitted by contact with contaminated surfaces as well as in water or food. The virus thrives from November to April. Most children are infected by the time they are two years old, and although the disease can occur in adults, it is almost always mild and transitory. In children, the illness, whose symptoms are vomiting and watery diarrhea, and usually fever and abdominal pain as well, lasts between three days and a week. After they’ve had it once, there is some immunity, subsequent infections tend to be much milder than the first one.
There is no treatment except to provide oral rehydration therapy to counteract the effects of the diarrhea and prevent dehydration. About one out of every 40 kids with the disease will wind up hospitalized and on intravenous fluids. The diagnosis is usually made without a test to prove that rotavirus is the culprit, but there is a lab procedure that can detect antigens in a stool sample.
Because it’s so contagious, it’s important to follow the rules: keep children or adults with diarrhea separated from other kids; wash your hands often, and make sure everyone else in the family does, too, especially before meals and after changing a diaper or helping a kid use the toilet; use disposable paper towels for hand drying; keep toys, changing tables, bathrooms, and kitchen as clean as possible.
A recent British study suggests that bottle-feeding (with or without breast-feeding) is a risk factor for rotavirus infection, and that breast-feeding provides some protection against it. But the fact is that breast-fed or not, most kids will eventually get the disease.