Preamble

It was 200 years ago that Jenner was able to protect a man from the dreaded disease smallpox through vaccination. Since that time, through mass immunization efforts smallpox has been eradicated from the planet. Other miracles have taken place such as the elimination of polio from the Americas ( a disease that 40 years ago caused paralytic illness in almost 2,000 Canadians in one year) and the control of diseases that once maimed or killed In large numbers

 Nevertheless there are individuals who are hesitant about, or outright refuse immunization for themselves or for their children. There are several reasons for this that are important to appreciate:

Some patients have religious or philosophic objections; Some see mandatory vaccination as interference by the government into what they believe should be a personal choice; Others are concerned about the safety and/or efficacy of vaccines; Some may believe that vaccine-preventable diseases do not pose a serious health risk. Others believe that immunization is not "natural".

 It is important to listen to and try to understand a patient's concerns, fears, and beliefs about vaccination and to take these into consideration when offering vaccines. This will not only help to strengthen the bond of trust between patient and provider but will also help in deciding on the type of information that might be most effective in addressing the concerns.

 The purpose of this document is to address the common misconceptions about vaccination which are often cited by concerned parents as reasons to question the wisdom of vaccinating their children

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

Statements like this (variations include assertions that vaccines had absolutely no effect on disease rates) 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. Are we expected to believe that better sanitation caused the incidence of each disease to drop, coincidentally, just at the time a vaccine for that disease was introduced? Here are some examples to illustrate this:

 Invasive disease due to Haemophilus Jnfluenzae type b such as meningitis was prevalent until just a few years ago when conjugate vaccines that can be used in infants (in whom most of the disease was occurring) were finally developed. Since sanitation is no better now than it was in 1990, it is hard to attribute the virtual disappearance of Hib disease in children in recent years to anything but the introduction of routine immunization. Data from reportable disease surveillance systems revealed that from an estimated 2,000 cases a year prior to the availability of vaccine, there are now less than 52 cases per year being reported (with the majority in infants and children who have not been immunized).

 Varicella (chicken pox) can also be used to illustrate the point since modern sanitation has obviously not prevented cases from occurring each year - with almost all children getting the disease sometime in their childhood, just as they did 20 years ago, or 80 years ago. If diseases were disappearing, we should expect varicella to be disappearing along with the rest of them.

 We can also 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 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 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.

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.

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 outbreaks occurring in highly vaccinated populations, the cases who were immunized often outnumber those who were not -- even with vaccines such as measles, which we know to be about 90 to 95% effective in one dose.

 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 vaccinate will develop immunity. Most routine childhood vaccines have efficacy in the 85-90% range. Therefore, over the years there is a buildup of susceptible individuals (each year contributing 10-15% of its cohort). Second, in a country like Canada with high immunization coverage, 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 3 of the students have had their dose of measles vaccine, and so are considered vaccinated. However, among these 970, there would be about 97 who are not protected by the vaccine. When the student body is exposed to measles, every susceptible student becomes infected because measles is highly contagious. The 30 unvaccinated students will be infected of course. But of the 970 who have been vaccinated, we would expect the 97 who are not protected to fall ill. Therefore 97/127, or about 76% 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 had been vaccinated so the vaccine failures outnumbered the unvaccinated susceptibles. Looking at it another way, 10% of the children who were not vaccinated got measles, compared with only 10% 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. In this example, the vaccine was in fact 90% effective in preventing measles.

There are many case reports of harmful side effects from vaccines, including deaths. This proves that vaccines are not safe.

 The implication here is that the number of side effects reported is related to the safety of the product, and that the more adverse event reports received the more dangerous the vaccine. In addition, since not all adverse events are reported, this implies that vaccines are even more dangerous than the number of cases reported leads us to believe.

 This is misleading because reports of adverse events are only suspicions that are temporal1y associated with receipt of vaccine; reports should not be interpreted to imply 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 healthy problems or death. The point is that just because an adverse event has been reported, it does not mean it was caused by a vaccine. This fact is often, if not always overlooked by the media when adverse events are mentioned. 

In the United States, some anti-immunization groups also focus on so called "hot lots" of vaccine. They counsel parents to avoid certain lots of vaccine because more adverse events had been reported involving those lots than others. This is misleading because vaccine lots may vary in size from several thousand doses to several hundred thousand, and some are in distribution longer than others. Naturally a larger lot or one that is in distribution longer will be associated with more adverse events, simply by chance. AIso, 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  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.

 If the number and type of reports for a particular vaccine lot suggested that it was associated with more serious adverse events or deaths than are expected by chance, the federal government has not only the responsibility and will but the legal authority to immediately recall that lot.

 Every vaccine manufacturing facility and vaccine product is licensed. In addition, every vaccine lot is safety-tested by the manufacturer and by the federal Bureau of Biologics of the Drugs Directorate. A vaccine lot would be recalled at the first sign of problems. 

There is no benefit to anyone in allowing unsafe vaccine to remain on the market since vaccines are given to otherwise healthy children, the public would not tolerate them if they did not have to conform to the most rigorous safety standards 

Further, there will always be articles in the press or medical journals that report possible bad outcomes as a result of vaccination. Reports in medical journals are sometimes just preliminary findings to stimulate further work and provide an opportunity for exchange of information. It is necessary to assess many sources before drawing final conclusions As well, articles in some newspapers and magazines are written from a very biased standpoint. Their manner of presenting the data can be misleading. and must be interpreted with caution.

 Assertions about the link between vaccines and bad outcomes are rarely corroborated.

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 much antivaccine literature. 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 one per thousand to one per million doses), and some are so rare that risk cannot be accurately assessed. This is the case for severe neurological illness (including encephalopathy). Most often, the illness attributed to a vaccine occurs much more frequently in individuals with no recent vaccination. 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. Each death reported to the Canadian vaccine-associated adverse events surveillance system is thoroughly examinee to ensure that it is not related to a new vaccine-related problem

 As to long term effects, many vaccines have been in use for decades with no evidence of any long-term adverse effects The requirements for licensing vaccines in Canada are stringent and ensure that excellent research into potential adverse effects has been done prior to widespread use. No long term effects have been associated with any vaccine currently in use. Any such claims have not been substantiated. 

But looking at risk 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. The examples from those countries who have stopped or decreased their immunization programs have illustrated this time and again. In fact, to have medical intervention is effective in preventing disease as vaccination and not use it would be unconscionable.

DTP Vaccine and SIDS

 One myth that persists is that DTP vaccine causes Sudden infant Death Syndrome (SIDS). This belief came about because a moderate proportion of SIDS deaths occur in children who have recently been vaccinated with DTP; and on the surface, this seems to point toward a causal connection. But this logic is faulty, you might as well say that eating bread causes car crashes, since most drivers who crash their card could probably he shown to have eaten bread within the past 24 hours.

If you consider that most SIDS deaths occur during the same range of ages when 3 shots of DTP are given, you would expect DTP shots to precede a fair number of SlDS deaths simply by chance. In fact, when a number of well-controlled studies were conducted during the 1980’s, they found, nearly unanimously, that the number of SIDS deaths temporally associated with DTP vaccination was within the range expected to occur by chance. In other words, the SIDS deaths would have occurred even if no vaccinations had been given. In fact, in several of the studies children who had recently had a DTP shot were less likely to get SIDS. The Institute of Medicine in the United States reviewed the evidence regarding SIDS and vaccination and reports that "all" controlled studies that have compared immunized versus non-immunized children have found either no association...or a risk...of SIDS among immunized children " and concludes that "the evidence does not indicate a causal relation between DTP vaccine and SIDS.

Vaccine-preventable diseases have been virtually eliminated from Canada, 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. However, some of them are still quite prevalent -- even epidemic-- in other parts of the world. Travelers can unknowingly bring these diseases into the country, and if we were not protected by vaccinations these diseases could quickly spread throughout the population, causing epidemics here. At the same time, the relatively few cases we currently have could very quickly become tens 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.

 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 people around us to stop the spread of disease without doing what we can as well. One important example is vaccination against rubella A woman who contracts rubella during pregnancy is at high risk of having a baby with congenital rubella syndrome, a devastating illness. Children who are not immunized against rubella can infect those around them.

 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 and 50. according to a 1994 report by the Institute of Medicine in the United States entitled 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 3iving various combinations of vaccines simultaneously. In fact, simultaneous administration of any vaccine would not be recommended by Health Canada or its national expert advisory committee 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 cause no greater risk for adverse side effects. Research is currently under way to find ways to combine more antigens in a single vaccine injection. This will assure all the advantages of the individual vaccines, but require fewer shots. 

There are two practical factors in favour of giving a child several vaccinations during the same visit. First, we want to immunize children as easily 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 of 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 parent both time and money and may be less traumatic for the child.