Vaccines and the immune system

Vaccines are responsible for preventing many infectious diseases. According to the World Health Organization, vaccines prevent more than two million deaths per year around the world. Read more to find out how they protect you and your family.

Benefits of vaccines

We tend to forget that, up until the 18th century, 25% of children died before their first birthday, and half did not reach adulthood. Today in Canada, life expectancy at birth is close to 80 for men and slightly higher for women. Together with the development of antibiotics and public health measures, vaccines are part of this success story.

Vaccines have helped eradicate measles, smallpox and polio epidemics in many countries. Largely thanks to vaccination, today infectious diseases account for less than 5% of deaths in Canada.


How do vaccines work?

When our immune systems are deliberately exposed to a virus or bacteria that would normally make us sick, the body responds by producing antibodies. The next time we’re exposed to the microbe, our antibodies recognize it and respond more quickly. Thanks to vaccines, our bodies are better able to fend off an attack if the microbe comes our way in the future.

In other words, vaccines get the immune system ready to fight infection. Since vaccines consist of dead or weaker versions of the infectious microorganism, there is usually no risk of catching the disease. 

Remember: Vaccination not only protects the people who get immunized but also indirectly protects other people through something called “herd immunity.” For example, if a lot of people get the flu shot in the fall, fewer people in the community are likely to catch the flu and pass it on. This principle applies to all vaccines, which is why it’s so important for everyone to get their vaccinations.

Who can get vaccinated?

The Québec Immunization  Program has developed a vaccination schedule for the entire population of the province. The program provides the vaccines listed in the schedule free of charge. The government considers these vaccines essential to protect people against possible disease outbreaks.
The immunization schedule indicates which vaccines are to be administered at what age. Other vaccines may also be recommended for a particular health problem, for work or lifestyle reasons, or for travel.

A number of vaccines must be given during childhood. Babies receive their first vaccines when they are two months old so that they are protected as soon as possible. To protect your children as they grow, you should have them vaccinated at the ages indicated in the schedule. Of course, you must consent for your child to receive the vaccines.

Flu vaccine

Influenza or the flu is a respiratory infection caused by the influenza virus. Symptoms include fever, extreme fatigue, cough, sore throat, headache, and muscle and joint pain. These symptoms appear suddenly, and will vary depending on the person’s age and health. 

Because the influenza virus spreads easily, vaccination is the best way to protect yourself from these symptoms and any resulting complications. Two kinds of flu vaccines are currently available: the injectable vaccine (or flu shot) and the intranasal (or nasal spray) vaccine. The nasal spray vaccine contains a weakened form of the live influenza virus, while the flu shot contains dead virus particles. Either way, these viruses can’t reproduce and so can’t give anyone the flu. Both types of vaccine are considered safe. The most common side effects of the flu shot are redness, pain and swelling at the injection site, along with fever and muscle pain. The most common side effects of the nasal spray vaccine are runny nose, congestion and headache.

Note that full vaccine immunity only develops two weeks after vaccination and lasts for at least six months. While effective, the flu shot does not provide full protection. Generally speaking, it protects against the flu in about 60% of healthy individuals. This varies depending on the virus strains used in the vaccine and the virus strains circulating in the population. Every season, the flu vaccine is updated to match the virus strains believed to be in circulation that year. Since the virus is constantly changing, it’s all the more important to get vaccinated each year. For more information about the flu and flu shot, don’t hesitate to talk to your pharmacist.

Ministère de la Santé et des Services sociaux


A vaccine for cancer?

In 2012, 185,000 new cases of cancer were diagnosed, and there were 75,000 cancer deaths in Canada. Cancer estimates for 2015 are even higher. Given the magnitude of the disease, it's not surprising that many pharmaceutical companies are investing in research to sell new treatment options, such as vaccines. The idea is that vaccines could prevent certain types of cancer or even cure them by stimulating the immune system to destroy cancer cells itself.

In fact, cancer preventive vaccines are already a reality. Two highly effective vaccines against two strains of human papillomavirus (HPV), which cause 70% of all cases of cervical cancer, are currently available in Canada. 

While the science is promising, remember that a healthy lifestyle is still the best prevention strategy and will help you avoid half of all cancers, if not more.

Canadian Cancer Society

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