Vaccines are one of the greatest medical advances of all time. Vaccination programs have saved millions of lives. Your body’s immune system acts like a security system to protect you against invading viruses, bacteria and other microbes. When harmful microbes make it past your skin, mucous and other surface barriers, they trigger the immune response. This involves white blood cells and antibodies that target specific microbes. Antibodies tag the microbe so your immune system can recognize it. If this microbe attacks in the future, your body destroys it.

Natural immunization occurs due to infection. Active immunization employs a vaccine to stimulate the immune response. Vaccines cause your body to create and store away antibodies for microbes that have never infected you. Vaccines are truly amazing - they protect against a disease without causing the disease. So even if you have never encountered the flu virus or the Covid-19 virus, vaccines will protect you from them.

Influenza, or the flu, can be a serious disease. Every flu season millions of people catch the flu and thousands die. Getting an annual flu vaccine helps shield you from the virus. Although the shot or nasal spray may not provide total protection, the vaccine lessens the severity of your illness and reduces the risk of complications, so it's worth getting.

Flu viruses evolve quickly, so last year's vaccine may not protect against this year's viruses. New flu vaccines are released every year to keep up with rapidly adapting viruses and to work against new strains. Most flu vaccines are quadrivalent, protecting against four different flu viruses: an influenza A (H1N1) virus, an influenza A (H3N2) virus, and two influenza B viruses.

There are many types of vaccines. The most common for the flu are inactivated vaccine, live attenuated vaccine, and vaccines made using recombinant DNA technology. The first Covid-19 vaccines used a new messenger RNA technology. All of these vaccines train your immune system to destroy the actual microbes if they attack your body later.

Thanks to vaccines, humans have been able to obliterate deadly diseases such as smallpox and polio, as well as reduce the prevalence of the flu, measles, HPV, Covid-19 and dozens of other illnesses. Vaccines slow the spread of the disease and save lives, protecting each person who takes them and society as a whole.