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Is There Such A Thing As Too Many Vaccines?

04/26/2017 11:51 EDT | Updated 04/26/2017 12:22 EDT
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Doctor pediatrician injecting vaccine to cute african girl

Vaccines are biological miracles: They train our own immune systems to recognize and stop dangerous viruses and bacteria from causing disease. Thanks to vaccines, parents no longer have to worry about diseases that used to routinely pose a threat to babies and young children -- from measles to polio to rotavirus.

But some parents wonder if all these vaccines will overwhelm a young immune system.

The simple answer is: No.

Babies are exposed to thousands of bacteria and viruses each day when they crawl, eat, or touch toys. Studies show that a normal immune system can quite easily respond to about 10,000 different proteins (antigens) at any one time. Since vaccines contain even fewer antigens than all the bacteria and viruses we are exposed to every day, a few vaccine doses (even when given at the same time) cannot overwhelm the immune system.

Even more so, vaccines are designed to contain very few antigens, which are enough to create protection from the specific bacteria or virus that is targeted. Thanks to advances in biotechnology, newer vaccines have even fewer antigens than older ones.

Some parents are tempted to deviate from the recommended immunization schedule and "spread out" vaccines. As a doctor who treats children, I worry about parents delaying vaccines because the vaccine schedule is designed to protect babies and young children when they are most at risk. The National Advisory Committee on Immunization is composed of experts who study diseases and vaccines, and recommend a schedule that takes into account the best timing for protection.

No child should suffer from a disease that can be prevented by vaccines.

Delaying immunization to a later date than recommended puts your child at risk for diseases that can be prevented. Avoiding booster shots can also put your child at risk, since some vaccines work better when they are 'boosted' with additional shots.

All vaccines used in Canada undergo intense study to prove that they are safe. Their safety and effectiveness is monitored on an ongoing basis. That's how we know that some immunizations lose their effectiveness over time and need a booster. Ongoing monitoring also warns us about (rare) severe reactions--more than the usual sore arm or slight fever that lasts a day. Vaccines used in Canada are very safe.

Through social media, parents are often exposed to misinformation about vaccines. I encourage parents to always check where the information is coming from and ensure that it is credible. Reliable websites are hosted by expert organizations such as Immunize Canada, which represents organizations including the Canadian Paediatric Society and the Public Health Agency of Canada. Immunize Canada has produced a helpful guide to find information on the Internet you can trust.

As a physician, I see the illnesses caused by vaccine-preventable diseases. No child should suffer from a disease that can be prevented by vaccines. I also see children who can't be immunized because of a medical condition such as cancer, and who rely on others around them to be immunized so the virus or bacteria does not spread. We all play an important role in preventing infections that we once feared.

Vaccines work. Get immunized!

Dr. Nicole Le Saux is Vice-Chair of Immunize Canada and a paediatrician at the Children's Hospital of Eastern Ontario (CHEO) in Ottawa.

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