Common Misconceptions about vaccination

Dr. M. Vijayalakshmi, M.D (Peds), M.D (USA), F.A.A.P, DAA

"Adapted from the material provided by Centers for Disease Prevention and Control"

Common Misconceptions about vaccination

A large information about vaccinations is available to parents now. This is good, because parents should have access to any information that will help them make informed decisions about vaccination. However, information is sometimes published that is inaccurate or can be misleading when taken out of context.

Following are five misconceptions that is commonly used by those who oppose vaccinations in India . Provided below are explanations of why they are misconceptions.

  • Misconception #1: Diseases had already begun to disappear before vaccines were introduced, because of better hygiene, nutrition and sanitation.

    Statements like this are very common in anti-vaccine literature, the intent apparently being to suggest that vaccines are not needed. Improved socioeconomic conditions have undoubtedly had an indirect impact on disease. Better nutrition, not to mention the development of antibiotics and other treatments, have increased survival rates among the sick; 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.

    Here, for example, is a graph showing the reported incidence of measles from 1950 to the present.


    There were periodic peaks and valleys throughout the years, but the real, permanent drop in case of measles in the U.S. coincided with the licensure and wide use of measles vaccine beginning in 1963. Graphs for most other vaccine-preventable diseases show a similar pattern. Are we expected to believe that better sanitation caused incidence of each disease to drop, just at the time a vaccine for that disease was introduced?

  • Misconception #2: majority of people who get disease have been vaccinated.

    This is another argument frequently found in anti-vaccine literature - the implication being that this proves vaccines are not effective. In fact it is true that in an outbreak those who have been vaccinated often outnumber those who have not - even with vaccines such as measles, which we know to be about 98% effective when fully used as recommended.

    This is explained by two factors. No vaccine is 100% effective. Most routine childhood vaccines are effective for 85% to 95% of recipients. For reasons related to the individual, some will not develop immunity. The second fact is that in a country such as the United States the people who have been vaccinated vastly outnumber those who have not. Here's a hypothetical example of how these two factors work together.

    In a high school of 1,000 students, none has ever had measles. All but 5 of the students have had two doses of measles vaccine, and so are fully immunized. The entire student body is exposed to measles, and every susceptible student becomes infected. The 5 unvaccinated students will be infected, of course. But of the 995 who have been vaccinated, we would expect several not to respond to the vaccine. The efficacy rate for two doses of measles vaccine can be higher than 99%. In this class, 7 students do not respond, and they, too, become infected. Therefore 7 of 12, or about 58%, of the cases occur in students who have been fully vaccinated.

    This doesn't prove the vaccine didn't work - only that most of the children in the class had been vaccinated, so those who were vaccinated and did not respond outnumbered those who had not been vaccinated. Looking at it another way, 100% of the children who had not been vaccinated got measles, compared with less than 1% of those who had been vaccinated. Measles vaccine protected most of the class; if nobody in the class had been vaccinated, there would probably have been 1,000 cases of measles.

  • Misconception #3: Vaccines cause many harmful side effects, illnesses, and even death - not to mention possible long-term effects we don't even know about.

    Vaccines are actually very safe, despite implications to the contrary 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 Paracetamol 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. As for vaccines causing death, again so few deaths can plausibly be attributed to vaccines that it is hard to assess the risk statistically. Of all deaths reported to VAERS (Vaccine Adverse Event Reporting System in the USA) between 1990 and 1992, only one is believed to be even possibly associated with a vaccine. Each death reported to VAERS is thoroughly examined to ensure that it is not related to a new vaccine-related problem, but little or no evidence suggests that vaccines have contributed to any of the reported deaths. The Institute of Medicine in its 1994 report states that the risk of death from vaccines is "extraordinarily low."

    Risk from Disease versus Risk from Vaccines

    Measles and Rubella vs. MMR Vaccine

    Even one serious adverse event 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 the more disease, there would be serious sequel and more deaths. But looking at risk alone is not enough - you must always look at both risks and benefits. 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.

    Measles MMR
    Pneumonia: 6 in 100 Encephalitis or severe allergic reaction:
    1 in 1,000,000
    Encephalitis: 1 in 1,000
    Death: 2 in 1,000
    Congenital Rubella Syndrome: 1 in 4 (if woman becomes infected early in pregnancy)

    Diphtheria DTaP
    Death: 1 in 20 Continuous crying, then full recovery: 1 in 1000
    Death: 2 in 10 Convulsions or shock, then full recovery: 1 in 14,000
    Pertussis (Whooping Cough)
    Pneumonia: 1 in 8 Acute encephalopathy: 0-10.5 in 1,000,000
    Encephalitis: 1 in 20 Death: None proven
    Death: 1 in 1,500

    The fact is that a child is far more likely to be seriously injured by one of these diseases than by any vaccine. 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.

    There also have been information in the media over the last many years suggesting possible link between Autism and vaccinations. Many organizations like CDC, IOM and AAP have funded extensive studies which all have failed to find any link between the two.

  • Misconception #4:Vaccine-preventable diseases have been virtually eliminated from the United States and many parts of the world, so there is no need for my child 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 and many other countries. However, some of them are still quite prevalent - even epidemic - in many parts of the world. Travelers can unknowingly bring these diseases into your country, and if we were not protected by vaccinations these diseases could quickly spread throughout the population, causing epidemics in your country.

    We should still be vaccinated, then, 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. Travelers are especially vulnerable. In 2005 and 2006, outbreaks of measles and mumps occurred in several states within the U.S. The measles outbreak began in a group of travelers (who had not been vaccinated) upon their return from a trip to Romania where they had been exposed to measles.

    The second reason to get vaccinated is to protect those around us. A small number of persons cannot be vaccinated for medical reasons such as a severe allergy to vaccine components, and a small percentage simply do not respond to vaccines. These persons are susceptible to disease, and their only hope of protection is that people around them have been successfully vaccinated and cannot pass disease along to them. A successful vaccination program, like a successful society, depends on the cooperation of every individual to ensure the good for all. We would think it irresponsible of a driver to ignore all traffic regulations on the presumption that other drivers will watch out for him or her. In the same way, we shouldn't rely on people around us to stop the spread of disease if we ourselves can be vaccinated.

  • Misconception #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.

    Children are exposed to many foreign antigens every day. Eating food introduces new bacteria into the body, and numerous bacteria live in the mouth and nose, exposing the immune system to still more antigens. An upper respiratory viral infection exposes a child to 4 - 10 antigens, and a case of "strep throat" to 25 - 50. According to Adverse Events Associated with Childhood Vaccines, a 1994 report from the Institute of Medicine, "In the face of these normal events, it seems unlikely that the number of separate antigens contained in childhood vaccines . . . would represent an appreciable added burden on the immune system that would be immunosuppressive." And, indeed, available scientific data show that simultaneous vaccination with multiple vaccines has no adverse effect on the normal childhood immune system.

    A number of studies have been conducted to examine the effects of giving various combinations of vaccines simultaneously. In fact, neither the Advisory Committee on Immunization Practices (ACIP) nor the American Academy of Pediatrics (AAP) would recommend the simultaneous administration of any vaccines until such studies showed the combinations to be both safe and effective. 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 ACIP and AAP recommend simultaneous administration of all routine childhood vaccines when appropriate.

    There are three 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. Second, giving several vaccinations at the same time will mean fewer office visits for vaccinations, which saves parents both time and money and may be less traumatic for the child. Third, combination vaccines means less shots or pokes for the child.