Table 2.

Answers to questions commonly asked by parents

Benefits of vaccines
  • “Can my child still get a disease even after being vaccinated?”34,35“This is not very common. More than 95% to 99% of children develop immunity after vaccination, which further improves with boosters.33 Vaccinated children often get milder symptoms even if they do get the disease”
  • “Do we still need to give vaccines, as many of the diseases are no longer here?”34“Your child might never need the protection offered by vaccines, but you do not want her or him to be lacking the protection needed in the event of an outbreak, which still happens in Canada for diseases such as measles, mumps, and whooping cough. Vaccination is similar to wearing a seat belt; you do not expect to be in a collision, but in the unlikely event that you are in one, you want to be protected. Even if right now your child is able to avoid infectious diseases as everyone around is vaccinated, what if she or he decide to work elsewhere in the world later in life?31 Even if your child never travels internationally, others in your community travel and can bring back diseases”36,37
Safety of vaccines
  • “How do we know vaccines are safe?”25,38“The safety of each vaccine is carefully checked before it is licensed and it is monitored on an ongoing basis after licensing. If a serious side effect is found, the vaccine is pulled from the market. I understand you might be concerned, but I truly believe that the risk of diseases is greater than any risk posed by vaccines”39,40
  • “How do we know vaccines do not cause long-term health problems?”34,40“Based on more than 50 years of experience with vaccines, it is not likely that vaccines cause unexpected long-term problems. Studies have found no relationship between vaccination and development of chronic diseases”25
  • “Can my child get a disease from the vaccine itself?”34,41“Inactivated or killed vaccines, which make up most vaccines, cannot give you the disease from the vaccine itself. Live vaccines contain viruses that are weakened, so occasionally you might get a mild case of disease (for example, a few spots of what look like chickenpox or measles). This is not harmful and actually means that the vaccine is working”
  • “Aren’t the ingredients in vaccines toxic?”34“Some ingredients in vaccines might be toxic, but only at much higher doses. Remember, even water can be toxic at high enough doses. The ingredients in vaccines are there to keep them from getting contaminated by bacteria and to make them work better”
  • “Why is aluminum in vaccines?”38“Aluminum is used to boost the immune system.34 It is commonly ingested from food, drinking water, and medicine. In fact, the amount of aluminum found in a vaccine is similar to the amount present in breast milk and infant formula”38
  • “Why is formaldehyde in vaccines?”38“Formaldehyde is used as a preservative. It is found naturally in foods.42 In fact, more formaldehyde is present in a pear than in all the vaccines a child receives”31
  • “Should I be concerned about mercury in vaccines?”42“Thimerosal is a form of mercury different from naturally occurring mercury like what is found in fish and cannot build up in a person’s body. Multiple studies have shown that thimerosal in vaccines is not harmful. It is no longer found in any routine childhood vaccines.25 It is only used as a preservative in certain influenza vaccines to prevent contamination”
  • “Doesn’t the MMR vaccine cause autism?”38,39,41“We all want answers to the cause of autism, including me. But study after study has shown that vaccines do not cause autism.43 One study showed that the rates of autism were the same in groups of children who received the vaccine compared with those who did not receive the vaccine”
Immunity related
  • “Isn’t vaccination unnatural?”34“No, vaccines invite the immune system to produce its own protection, just like a natural infection would.31 The difference is your child does not have to get sick first to develop these protective antibodies”
  • “Isn’t natural immunity better than vaccination?”36,42“Although natural immunity might give better immunity than vaccines do, the risks are much higher. With natural infections, a child might develop complications such as permanent brain damage, deafness, blindness, and death. On the other hand, if your child is exposed to a disease after being vaccinated, he or she would already be armed and able to fight it off”35
  • “Can’t so many vaccines overwhelm my child’s immune system?”25,34,42“A child’s immune system has to deal with thousands of germs on a daily basis starting at birth. Scientists estimate that babies can handle up to 10 000 shots at one time.25 By stimulating the immune system to do what it is naturally meant to do, vaccines make your child’s immune system better at fighting off these diseases”38
  • MMR—measles-mumps-rubella.