Misperceptions About Value of Vaccines May Lead Parents to Question Their Use


Mark Vogel, (703) 299-0217
Carrie Schum, (202) 973-5800

Junio 1, 2000

WASHINGTON, D.C. — At an American Medical Association media briefing on infectious diseases here today, Bruce Gellin, M.D., MPH, warned that the U.S. immunization program is at risk of becoming a victim of its own success. An alarmingly high percentage of parents hold misperceptions about the value and safety of vaccines, which may lead them to refuse some or all immunizations for their children. Even a small drop in the immunization rate may lead to a resurgence of infectious diseases that are currently nearly eliminated from the U.S.

Dr. Gellin is the executive director of the National Network for Immunization Information (NNii), a educational effort sponsored by the Infectious Diseases Society of America (IDSA), Pediatric Infectious Diseases Society (PIDS), American Academy of Pediatrics (AAP) and the American Nurses Association (ANA). NNii is based at Vanderbilt University School of Medicine in Nashville, Tenn.

‘There’s a lot of misinformation out there about vaccines. This isn’t the parents’ fault, but unless we can correct these misperceptions, parents may make bad decisions based on bad information. The reasons why so many parents have important misunderstandings about vaccines are complex, but the scientific process itself, and the media, are each partly to blame’ notes Gellin. ‘Even though the vast majority of the scientific data, and virtually all doctors, support the fact that vaccines are safe and effective, research on highly unlikely hypotheses about harmful side effects is often taken out of context. The media tend to do stories that make highly speculative hypotheses sound not only plausible, but likely.’

Currently, hypotheses that vaccines cause autism and diabetes are causing alarm among some parents. The best available scientific evidence does not support either of these hypotheses.

Gellin says the Internet is one means by which misinformation is spread. ‘Patients now come into doctors offices with print-outs from the Internet about the supposed harm caused by a certain vaccine, believing the information is fact. Often, the scientific data does not support the conclusion, but these sites usually contain powerful anecdotes from parents who believe their children were harmed by a vaccine. That’s very believable to another parent.’

Dr. Gellin says there are very real risks from not receiving vaccinations, risks that every parent should understand before they make a decision not to immunize their child. ‘If enough people refuse vaccination- and it can take a decline of only a few percentage points in the immunization rate- all children in the community are placed at greater risk. Despite their incredible performance, vaccines are not 100% effective. For example, one out of 100 children fully immunized against measles is still susceptible to the disease. Unvaccinated children are at greater risk themselves, and they place these susceptible children, and children who cannot be given the vaccine for medical reasons, at greater risk.’

A July 7, 1999 JAMA article cited by Gellin found that individuals who declined to be vaccinated for measles for religious or philosophical reasons were 35 times more likely to contract the disease than those who received the vaccine. This risk spills over into the community at large. Gellin cites Ireland and the Netherlands as examples of where this has happened recently. Ireland has had a decrease in the measles vaccination rate over the last few years. Because of this decrease, and the fact that measles is such a highly contagious disease, a measles epidemic is currently raging in Dublin with over 700 cases and many children being hospitalized. The outbreak is now also spreading to surrounding counties. The Netherlands also recently had a large measles outbreak- over 3,000 cases and several deaths — in one area where a portion of the community declined to immunize their children.

Complacent Attitude Towards Vaccinations a Problem

Dr. Gellin says because infectious diseases have been so well controlled in the U.S. through the use of vaccines, there has been a shift in perception about how necessary vaccines are.

‘Most parents today have never seen these diseases, and therefore don’t know how serious these diseases can be. They see these as diseases of yesteryear’ he says. In the United States, measles has decreased by 99 percent, from three to four million cases a year in the 1950’s and 60’s to 100 cases last year. ‘Unless they have traveled overseas, none of the first-year medical students in my class has ever even seen measles’ Gellin notes.

Diseases that that are recommended for childhood immunization include polio, measles, mumps, rubella, Hib, hepatitis B, diphtheria, pertussis (whooping cough), tetanus, and varicella (chickenpox). All these diseases still exist and remain a health threat for those who have not been immunized.

According to Dr. Gellin, some parents say, ‘Look, there’s not much disease in my community, so my kid isn’t likely to get sick. Why should I risk a complication from being vaccinated?’ The reasons, according to Gellin, are that ‘the risks and consequences of getting these diseases are far greater than the small risks associated with the immunizations.’ Also, Gellin notes, ‘the decision not to vaccinate your child is a decision that places other children in the community at greater risk. There are many things we do to protect everyone in society. Four-way stop signs, for example. You can run that stop sign if you are certain that everyone else will stop. If someone else runs their stop sign too, however, you may be in big trouble.’

The organization Dr. Gellin directs, the National Network for Immunization Information, focuses on providing the public with understandable, science-based information on vaccine safety. The organization is creating a resource for health care professionals, available in August, which will help them to provide simple, accurate answers to their patients’ questions about immunizations. NNii is also building a new website that will contain this information, as well as information for parents and legislators. More information about NNii can be found at