Why Do Some People Experience Side Effects After COVID-19 Vaccines?

Did you know? August is National Immunisation Awareness Month (NIAM) held annually to increase the awareness of vaccination for people of all ages. It has been months since the beginning of the National COVID-19 Immunisation Programme in Malaysia.

As Malaysia continues to roll out the immunisation programme smoothly and effectively in the effort to curb and end the pandemic, we would like to highlight some common side effects of COVID-19 vaccines, and why it is perfectly normal if you experience them.

Common Side Effects of COVID-19 Vaccines^1,2

·         - Pain/swelling at injection site

·         - Fever

·         - Tiredness

·         - Headache

·         - Chills

Why is it Normal to Catch These Side Effects from Vaccines?

Imagine our immune system as a military of army that protects our body (in this case, our homeland) against invaders and intruders (pathogens such as virus, bacterium, fungus, parasite). When these foreign particles invade us, our immune system triggers a series of responses to trap, deter and get rid of these pathogens from our bodies by increasing blood flow and raising our body temperature, resulting in common symptoms like fever or chills.¹

To help you understand better, vaccines also contain parts of the pathogens, known as antigens to activate our immune system the same way, but they are either weakened or inactive therefore will not make us sick. When injected, our military of army will detect it as an invader hence prompted to fight against it. As a result of these immune response are working, we tend to experience mild to moderate symptoms such as fever, pain at injection site and chills.³

Some vaccines require multiple doses, given weeks or months apart. This is necessary as to allow the production of long-lived antibodies and development of memory cells (B cells and T cells). This way, the body is trained capture and memorise what the invaders look like and how best to fight against them when exposed in the future.⁴

What Should You Do If You Experience These Side Effects?

·         -  Monitor your body temperature regularly with a thermometer

·         - Drink plenty of fluids

·         - Apply cool cloth to relieve pain at injection site

The side effects after vaccination indicate that your immune system is building up the protection and should go away after a few days. Not experiencing these side effects does not mean that your immune system is not working, instead it is working more quietly. Seek medical attention if your side effects are worrying you or do not seem to be going away after a few days.

References:

1.  World Health Organization. (2021, March 31). Side Effects of COVID-19 Vaccines. Retrieved from https://www.who.int/news-room/feature-stories/detail/side-effects-of-covid-19-vaccines

The Special Committee for Ensuring Access to COVID-19 Vaccine Supply (JKJAV). (2021, February 18). National COVID-19 Immunisation Programme. Retrieved from https://www.vaksincovid.gov.my/upload/media/National_COVID-19_Immunisation_Programme_English.pdf

3. World Health Organization. (2020, December 8). How do Vaccines Work? Retrieved from https://www.who.int/news-room/feature-stories/detail/how-do-vaccines-work?gclid=CjwKCAjwrPCGBhALEiwAUl9X0-pumfnOo1XFTIV3hMG4nTHiBNBs0Ikc31AI1Y5fF_vY0bVbRbiJThoCEE8QAvD_BwE

4.  Centers for Disease Control and Prevention (CDC). (2021, March 27). Understanding How COVID-19 Vaccines Work. Retrieved from https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/how-they-work.html