I share your concern about your grandchildren. Vaccines can protect them from many serious infections. Unfortunately, there is a lot of misinformation on internet and social media; some parents are misguided, and refused to have their children vaccinated.

Smallpox vaccine was the first one discovered and used around the world. It eradicated smallpox, which killed and scarred many throughout human history. As a result, smallpox vaccine is not necessary any more.

Polio is the second disease that vaccines try to eradicate. Poliovirus infection can cause paralysis, mostly in children and young adults. Polio vaccine is very effective, it wiped out polio in most parts of the world. There are pockets in several countries where polio infection still exists. As a result, children need polio vaccine to keep them protected.

Scientists have been trying to produce vaccines for different germs. Some viruses were grown in the laboratory for many generations, and were “tamed” to produce mild infection, but not the illness. This was how measles, mumps, rubella, and varicella (chickenpox) vaccine (MMRV) was produced.

Other vaccines were produced by using components of viruses and bacteria that can induce immunity, but won’t cause an infection. Human papilloma virus (HPV) vaccine that can prevent cervical cancer, as well as Haemophilus influenzae (Hib) and meningococcal vaccines that prevent meningitis, are produced using this technique.

The science behind viral, bacterial, and parasitic infections is very complex; different germs infect us in different ways. That is why infectious disease is a specialty within medicine.

Vaccine research often takes years, with teams of scientists collaborating around the world. Once identified, vaccines are tested carefully to ensure their effectiveness as well as safety. Only a few vaccine manufacturers are licensed in North America to produce these vaccines; they have to follow stringent regulations. Vaccines also need to be transported and stored properly.

A group of scientists are tasked by Health Canada to review all research data before approving any vaccine. Monitoring continues after a vaccine is approved to track side effects of the vaccine.

Vaccines stimulate our immune system to produce antibodies, and alert our white blood cells to recognize and fight the germs so that we won’t get sick. After vaccination, most of us are protected. However, a small percentage of individuals may not respond as well to the vaccine. For many germs, we need 95% or more of the population to be vaccinated to prevent the spread of these germs: this is called herd immunity.

Measles is a good example. United States and Canada were on the verge of eliminating measles since the turn of this century. Unfortunately, Dr Wakefield, a researcher in England, falsely associated measles vaccine as the cause of autism. Many parents were scared, and refused to allow their children to be vaccinated. In addition, some religious sects also would not allow immunization.

As a result, there have been outbreaks of measles infection in Europe and North America. Some local governments have started mandatory vaccination to prevent further outbreaks. In other countries, they cannot afford to provide measles vaccine to children; large outbreaks and epidemics continue to occur in these countries.

It is difficult for the general public to fully understand the science behind vaccines, how they are produced and how they protect us. Reading medical literature after putting their children to bed is hardly something most parents can do, and it is not easy to understand. Most rely on internet search and social media. Unfortunately, there is a large group of people who are against vaccination; they spread false information to further their cause.

I would suggest that you go to the parents website of Canadian Paediatric Society (www.caringforkids.cps.ca) to look for good information about vaccines. You can also show this column to your daughter. Furthermore, if she was born before 1995, she may have received only one dose of MMR vaccine; she will need a second dose for full protection.