A huge amount of data regarding childhood vaccines is currently available to parents and caregivers. Media sources in general, and the Internet in particular, have been responsible for giving us access to an enormous amount of information on the topic. This access is a real advantage to those who need to make responsible decisions about childhood vaccinations. Unfortunately, it’s easy to published information that is inaccurate or misleading, especially when the facts are taken out of context.
People who are opposed to vaccination on principle – those with religious or philosophic objections – are unlikely to be influenced by scientific data. But the facts are so overwhelmingly in favor of vaccination that even skeptics are hard-pressed to refute them. Anti-vaccine groups tend to stress the same arguments repeatedly; many of these arguments use anecdotal support in place of real evidence to make their point. Here, the US Centers for Disease Control and Prevention (CDC) address five of the most common misconceptions about vaccination.
1. Due to better hygiene and sanitation, diseases had already begun to disappear before vaccines were introduced.
Improved socioeconomic conditions and nutrition, not to mention the development of antibiotics and other treatments, have undoubtedly had an indirect impact on disease. In addition, less-crowded living conditions have reduced disease transmission and lower birth rates have decreased the number of susceptible household contacts. But looking at the actual incidence of disease over the years can leave little doubt of the significant direct impact vaccines have had, even in modern times.
A graph showing the reported incidence of measles from 1950 to the present shows periodic peaks and valleys throughout the years, but the only real, permanent drop coincided with the licensure and wide use of measles vaccine beginning in 1963. Graphs for other vaccine-preventable diseases show a roughly similar pattern.
Hib (haemophilus influenzae type b) vaccine is another good example, because Hib disease was prevalent until just a few years ago, when conjugate vaccines that could be used for infants were developed. (The previous vaccine could not be used for infants.) Hib disease in children has virtually disappeared in recent years – from an estimated 20,000 cases per year in 1990 to 1,419 cases in 1993, and still dropping.
Finally, we can look at the experiences of several developed countries after they let their immunization levels drop. In Great Britain, a drop in pertussis vaccination in 1974 was followed by an epidemic of more than 100,000 cases of pertussis and 36 deaths by 1978. In Japan, around the same time, a drop in vaccination rates from 70% to 20%-40% led to a jump in pertussis from 393 cases and no deaths in 1974 to 13,000 cases and 41 deaths in 1979. In Sweden, the annual incidence rate of pertussis per 100,000 children 0-6 years of age increased from 700 cases in 1981 to 3,200 in 1985. It seems clear from these experiences that not only would diseases not be disappearing without vaccines, but if we were to stop vaccinating, they would come back.
2. Some children still get an illness even though they have been vaccinated against it.
Most routine childhood vaccines are effective for 85% to 95% of recipients, but some individuals just don’t develop immunity even after vaccination. Because most children in the United States have been vaccinated, the few who don’t develop immunity and then become ill still outnumber those who become ill because they were not vaccinated. As a result, in an outbreak, those who have been vaccinated often outnumber those who have not. Percentages tell a more accurate story: the percentage of unvaccinated children who become ill is vastly higher than the percentage of those who were vaccinated.
3. Vaccines may cause harmful side effects.
Vaccines are actually very safe, despite the implications in many anti-vaccine publications. Most vaccine adverse events are minor and temporary, such as a sore arm or mild fever. These can often be controlled by taking acetaminophen before or after vaccination. More serious adverse events occur rarely (on the order of one per thousands to one per millions of doses), and some are so rare that risk cannot be accurately assessed. Research is underway by the U.S. Public Health Service to better understand which vaccine adverse events are truly caused by vaccines and how to reduce even further the already low risk of serious vaccine-related injury.
DTP Vaccine and SIDS
One myth that won't seem to go away is that DTP vaccine causes sudden infant death syndrome (SIDS). This belief came about because some children who died of SIDS had recently been vaccinated with DTP. But if you consider that most SIDS deaths occur during the same age range when DTP shots are given, you would expect DTP shots to precede a fair number of SIDS deaths simply by chance. The Institute of Medicine reported that "all controlled studies that have compared immunized versus non-immunized children have found either no association . . . or a decreased risk . . . of SIDS among immunized children."
4. Vaccine-preventable diseases have been virtually eliminated from the United States, so there is no further need for children to be vaccinated.
It's true that vaccination has enabled us to reduce most vaccine-preventable diseases to very low levels in the United States. However, some of them are still quite prevalent - even epidemic - in other parts of the world. Travelers can unknowingly bring these diseases into the United States, and if we were not protected by vaccinations these diseases could quickly spread throughout the population. At the same time, the relatively few cases we currently have in the US could very quickly become tens or hundreds of thousands of cases without the protection we get from vaccines.
We should still be vaccinated, for two reasons. The first is to protect ourselves. Even if we think our chances of getting any of these diseases are small, the diseases still exist and can still infect anyone who is not protected.
The second reason to get vaccinated is to protect those around us. A small percentage of people cannot be vaccinated (due to factors such as severe allergies), and a small percentage of people don't respond to vaccines. These people are highly susceptible to disease, and their only hope of protection is that the people around them are immune and cannot pass disease along to them.
5. Giving a child multiple vaccinations for different diseases at the same time increases the risk of harmful side effects and can overload the immune system.
A number of studies have been conducted to examine the effects of giving various combinations of vaccines simultaneously. These studies have shown that the recommended vaccines are as effective in combination as they are individually, and that such combinations carry no greater risk for adverse side effects. Consequently, both the Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics (AAP) recommend simultaneous administration of all routine childhood vaccines when appropriate.
There are two practical factors in favor of giving a child several vaccinations during the same visit. First, we want to immunize children as early as possible to give them protection during the vulnerable early months of their lives. This generally means giving inactivated vaccines beginning at 2 months and live vaccines at 12 months. The various vaccine doses thus tend to fall due at the same time. Second, giving several vaccinations at the same time will mean fewer office visits, which saves parents both time and money and may be less traumatic for the child.
Vaccines Save Lives
Looking at risk alone is not enough – we need to look at both risks and benefits. Even one serious adverse effect in a million doses of vaccine cannot be justified if there is no benefit from the vaccination. If there were no vaccines, there would be many more cases of disease, and along with them, more serious side effects and more deaths. For example, according to an analysis of the benefit and risk of DTP immunization, if we had no immunization program in the United States, pertussis cases could increase 71-fold and deaths due to pertussis could increase 4-fold. Comparing the risk from disease with the risk from the vaccines can give us an idea of the benefits we get from vaccinating our children.
Diphtheria has a death toll of 1 in 20; tetanus of 3 in 100, and pertussis kills 1 in 200 of those infected. The data on the DTP vaccine that protects against these diseases is as follows:
- Continuous crying, then full recovery: 1 in 100
- Convulsions or shock, then full recovery: 1 in 1,750
- Acute encephalopathy: 0-10.5 in 1,000,000
- Death: None proven
The fact is that a child is far more likely to be seriously injured by one of these diseases than by the vaccine that can prevent it. While any serious injury or death caused by vaccines is too many, it is also clear that the benefits of vaccination greatly outweigh the slight risk, and that many, many more injuries and deaths would occur without vaccinations. In fact, to have a medical intervention as effective as vaccination in preventing disease and not use it would be unconscionable.
This article includes information from:
US Centers for Disease Control and Prevention (CDC)
For information on current childhood vaccine recommendations, go to:
2002 US Recommended Childhood Vaccination Schedule
Article Created: 2002-08-13
Article Updated: 2002-08-14
Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.
