6 Misconceptions

1. Diseases had already begun to disappear before vaccines were introduced, because of better hygiene 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.

Hib vaccine is another good example, because Hib disease was prevalent up until just a few years ago, when conjugate vaccines that can be used in infants were finally developed. (The polysaccharide previously available could not be used for infants, in whom most of the disease was occurring.) Since sanitation is not better now than it was in 1990, it is hard to attribute the virtual disappearance of Hib disease in children in recent years (from an estimated 20,000 cases a year to 1,419 cases in 1993, and dropping) to anything other than the vaccine.

Varicella can also be used to illustrate the point, since modern sanitation has obviously not prevented nearly 4 million cases from occurring each year in the United States. If diseases were disappearing, we should expect Varicella to be disappearing along with the rest of them. But nearly all children in the United States get the disease today, just as they did 20 years ago or 80 years ago. Based on experience with the Varicella vaccine in studies prior to licensure, we can expect the incidence of Varicella to drop significantly now that a vaccine has been licensed for the United States.

Finally, we can look at the experiences of several developed countries that let their immunization levels drop. Three countries- Great Britain, Sweden, and Japan- cut back on the use of Pertussis vaccine because of their fear about the vaccine. The effect was dramatic and immediate. In Great Britain, a drop in Pertussis vaccination in 1974 was followed by an epidemic of more that 100, 000 cases of Pertussis and 36 deaths by 1978. In Japan, around the same time, a drop in vaccination rates from 70%-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.

Of more immediate interest is the major epidemic of diphtheria now taking place in the former Soviet Union, where low primary immunization rates in children and lack of booster immunizations in adults have resulted in an increase from 839 cases in 1989 to nearly 50,000 cases and 1,700 deaths in 1994, with the number of cases increasing by 2 to 10 fold each year. There have already been at least 20 imported cases in Europe and two cases in U.S. citizens working in the former Soviet Union.

2. The majority of people getting disease have been fully immunized.

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 the cases who are often vaccinated often outnumber those who were not- even with vaccines such as measles, which we know to be about 98% effective when used as recommended.This apparent paradox is explained by two factors. First, no vaccine is 100% effective. To make vaccines safer than the disease, the bacteria or virus is killed or weakened (attenuated). For reasons related to the individual, not all persons vaccinated will develop immunity. Most routine childhood vaccines have efficacy in the 85-95% range. Second, in a country like the United States the people who have been vaccinated vastly outnumber those who have not. How these two factors work together to result in outbreaks where the majority of cases have been vaccinated can be more easily understood by looking at a hypothetical example: 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 the 995 who have been vaccinated, we would expect several vaccine failures. The efficacy rate for two doses of measles vaccine can be as high as >99%, and in this class there are 7 vaccine failures, who become infected too. Therefore 7/12, or about 58%, of the cases are fully vaccinated.

As you can see, this doesn’t prove the vaccine didn’t work- only that most of the children in the class has been vaccinated, so the vaccine failures outnumbered the unvaccinated susceptible. Looking at it another way, 100% of the children who were not vaccinated got measles, compared with less than 1% of those who were. Measles vaccine protected most of the class; if nobody in the class had been vaccinated, there would have been 1,000 cases of measles.

3. There are "hot lots" of vaccine that have been associated with more adverse events and deaths than others. Parents should find the numbers of these lots and not allow their children to receive vaccines from them.

This misconception got considerable publicity recently when vaccine safety was the subject of a television news program. First of all, the concept of a "hot lot" of vaccine as it is used in this context is wrong. It is based on the presumption that the VAERS** reports a vaccine lot is associated with, the more dangerous the vaccine lot; and that by consulting a list showing the number of VAERS reports per lot, a parent can identify vaccine lots to avoid.

This is misleading for two reasons:

a. VAERS is a system for reporting events that are temporally associated with receipt of vaccine; VAERS reports should not be interpreted to imply causality. In other words, a VAERS report does not mean that the vaccine caused the event. Statistically, a certain number of serious illnesses, even deaths, can be expected to occur by chance alone among children recently vaccinated. While vaccines are known to cause minor, temporary side effects like soreness or fever, there is little, if any, evidence linking vaccination with permanent health problems or death. The point is that just because an adverse event has been reported to VAERS, it does not mean it was caused by a vaccine.

b. Vaccine lots are not the same. The sizes of vaccines lots might vary from several hundred thousand doses to several million, and some are in distribution much longer than others. Naturally a larger lot or one that is in distribution longer will be associated with more adverse events, simply by chance. Also, more coincidental deaths are associated with vaccines given in infancy than later in childhood, since the background death rates in children are highest during the first year of life. So knowing that lot A has been associated with X number of adverse events while lot B has been associated with y number would not necessarily tell you anything about the relative safety of the two lots, even if the vaccine did cause the events.

Reviewing published lists of "hot lots" will not help parents identify the best or worst vaccines for their children. If the number and type of VAERS reports for a particular vaccine lot suggested that it was associated with more serious adverse events or deaths than are expected by chance, FDA has the legal authority to immediately recall that lot. To date, no vaccine lot in the modern era has been found to be unsafe on the basis of VAERS reports.

Every vaccine manufacturing facility and vaccine product is licensed by the FDA. In addition every vaccine lot is safety-tested by the manufacturer. The results of these tests are reviewed by FDA, who may repeat some of these tests as an additional protective measure. FDA also inspects vaccine-manufacturing facilities regularly to ensure adherence to manufacturing procedures and product-testing regulations, and reviews the weekly VAERS reports for each lot searching for unusual patterns. FDA would recall a lot of vaccine at the first sign of problems. There is no benefit to either the FDA or the manufacturer in allowing unsafe vaccine to remain on the market. And since vaccines are given to otherwise healthy children, the American public would not tolerate them if they did not have to conform to the most rigorous safety standards. The mere fact is that a vaccine lot still in distribution says that it is considered safe by the FDA.

** The Vaccine Adverse Events Reporting System (VAERS) receives reports, from either providers or patients, of adverse events that occur after the administration of any vaccine.

4. 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 safe, despite implications to the contrary in much anti-vaccine literature (which sometimes quotes the number of reports received by VAERS, and allows the reader to infer that they all represent genuine vaccine side effects). The vast majority of vaccine adverse events are minor and temporary, like 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 1 per thousands to 1 per millions of doses), and some are so rare that risk cannot be accurately assessed. As to vaccines causing death, again there are so few deaths that could plausibly be attributed to vaccines that it is hard to assess the risk statistically. Of all deaths reported to VAERS 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 exists to suggest 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".But looking at risks alone is not enough- you must always 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, including death. For example, an analysis of the benefit and risk of DTP immunization has concluded that without an immunization program there could be a 71-fold increase in cases of Pertussis and a nearly 4-fold increase in deaths due to Pertussis in the United States. A comparison of the risk from disease with the risk from the vaccines that protect against them cab give us an idea of the benefits we get from vaccinating our children.The fact 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 them. In fact, to have a medical intervention as effective in preventing disease as vaccination and not use it would be unconscionable.

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 the already low risk of serious vaccine-related injury even further.

5. Vaccine-preventable diseases have been virtually eliminated from the United States, 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 Sates. However, some of them are still quite prevalent- even epidemic- in other parts of the world. Travelers can unknowingly bring these diseases into the U.S., and if we were not protected by vaccinations these diseases could quickly become tens or hundreds of thousands of cases without the protection we get from vaccines.

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 is small, the diseases still exist and can still infect anyone who is not protected. A few years ago in California a child who had just entered school caught diphtheria and died. He was the only unvaccinated pupil in his class.

The second reason to get vaccinated is to protect those around us. There is a small number of people who cannot be vaccinated (because of severe allergies to vaccine components, for example), and a small percentage of vaccine failures. These people are susceptible to disease, and their only hope of protection is that people around them are immune 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 of 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. In the same way we shouldn’t rely on the people around us to stop the spread of disease without doing what we can as well.

6. 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. Routine consumption of 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 between 4 and 10 antigens, and a case of "strep throat" to between 25-50. According to the Institute of Medicine’s 1994 report, Adverse Events Associated with Childhood Vaccines, "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 no adverse effects of simultaneous vaccination with multiple vaccines 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 American Academy of Pediatrics (AAP) nor the Advisory Committee on Immunization Practices (ACIP) would recommend simultaneous administration of any vaccines until such studies showed that 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 cause no greater risk for adverse side effects. Consequently, both the ACIP and the AAP recommend simultaneous administration of all routine childhood vaccines when appropriate. Research is currently underway to find ways to combine more antigens in a single vaccine injection (for example, MMR and chickenpox). This will assure all the advantages of the individual vaccines, but require fewer shots.

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. Therefore, doses the various vaccines tend to fall due at the same time. Second, if we can give several vaccinations at the same time it will mean fewer office visits for vaccinations, which saves parents both time and money and may be less traumatic for the child.

Program Components

6 Misconceptions