Immunizations: A Wonder of the Modern World

Why your vaccinations are important

In a book my son had on the wonders of the world, immunizations were listed as a wonder of the modern world.

I was surprised to see it in the same company as the pyramids of Giza and Niagara Falls but there are good reasons for this praise.

As doctors, we regret that immunizations have been a victim of their own success. Most people living in Canada have not witnessed a severe epidemic. Last year’s H1N1 pandemic was not as bad as feared. I have patients who still walk with a limp because of polio as a child.

A couple of years ago there was an outbreak of mumps at Dalhousie University that sent cases of it across the country but it didn’t spread because of good immunization levels in the general population. The mumps was a result of loss of long-term immunity in people born in the seventies, eighties and very early nineties. If you are born in those decades you should see your doctor about a booster for measles, mumps and rubella (MMR).

Normally, when you are infected, a bacteria or virus enters the body. Proteins on the outside of the virus or bacteria are recognized as foreign. The white blood cells in the blood or lymph nodes (like the glands in your neck) bring the virus to other white blood cells that can make an antibody that recognizes the foreign protein.

The antibodies travel in the blood and attach to any bacteria or virus they are designed to recognize and send a signal to bring white blood cells to kill the invader. There is a time delay between first recognizing the invader and making enough antibodies to find and destroy the invader. During that time the virus or bacteria can make multiple copies of itself and the immune system will have a lot to kill off.

When you have a cold, this is the time, early on, of fever, runny nose or cough that gradually improves as the immune system destroys the invaders.

The way immunization works is by fooling the immune system into thinking it has an infection that it needs to fight off. The shot introduces either a protein that is found on the outside of the bacteria or virus or dead or weakened viruses that can’t cause a major infection. The body finds this protein or virus and thinks it is under attack. The same process of making antibodies takes place but after a few days there aren’t the hoards of invaders to destroy. But the body is now ready to battle this invader. If you were to be infected with this the antibodies would already be in the blood stream ready to identify the infection.

Some immunizations (such as Hepatitis shots) require several shots to make long-term immunity; the body doesn’t think it is an important invader that it needs to keep antibodies in the blood, until it has been exposed several times.

The tetanus shot is only a little different. Tetanus is an infection that causes spasm (tetany) of muscles including those for breathing and swallowing and result in a terrible death. There are still several deaths every year in Canada. It starts with bacteria that live in soil. Anything that has dirt on it could have these bacteria, a rusty nail or a rose thorn or any dirty cut.

When the bacteria get under your skin, it makes copies of itself and the toxin (protein) that causes the muscle spasm. The bacteria don’t have to travel through your body, only the toxin does. So, the immunization is made to introduce the toxin so the body can destroy it before it latches onto the muscles. If you aren’t exposed to this toxin, the body gradually decreases the number of antibodies it makes.

A booster for tetanus is recommended every ten years to remind the body of this deadly threat.

There are some infections that have been difficult to make an immunization for. The HIV virus changes its outside proteins so often it has been difficult to find something the immune system can recognize today that will still label the HIV virus in a year.

The cholera virus also doesn’t have a good immunization. It invades through the bowel, when you drink infected water and antibodies in the blood don’t help as much. A lot of good information disproves any connection between MMR vaccines and autism. It’s good that we can finally put that myth to rest.

The Pertussis (whooping cough) immunization in the past gave babies high fevers that could trigger seizures. This shot has been completely reworked and is now approved up to age 55. It is also part of the booster at 15 years.

There may be several causes of allergies and asthma but I doubt that immunizations are the cause. Our cleaner lifestyle with less exposure to bacteria and viruses in general has been proposed as a cause. In that case, the solution is to let kids play in the dirt rather than withhold a shot that makes the body think it has been exposed to a bacteria or a virus.

The flu shot has to be repeated year to year because the proteins in the virus coat change and the antibodies from last year won’t recognize this year’s virus. Considering the influenza virus kills 4000 to 8000 people every year in Canada alone, it is still a major infectious disease.

As a doctor, it is disappointing that infectious diseases are still a major cause of death internationally. We thought that with good hygiene, immunizations and antibiotics we had that problem solved. Unfortunately, not everyone lives in conditions of good hygiene or has access to immunizations and many bacteria are becoming resistant to antibiotics.

The fight against infection continues.

Wilma de Groot, MD is a general practitioner practicing family medicine in Etobicoke.