Why it's normal to have mild side effects after getting a vaccine

Vaccines are designed to give you immunity so you don't get sick. It's common for people to have mild to moderate side effects after getting a vaccine. This is because the immune system is instructing the body to respond in certain ways: increasing blood flow so that more immune cells can circulate and raising the body's temperature to kill the virus.

Side effects that are usually mild to moderate, such as a low-grade fever or muscle aches, are normal and not a cause for alarm. These side effects are signs that the body's immune system is reacting to the vaccine, specifically the antigen (a substance that triggers an immune response), and is preparing to fight the virus. These side effects usually go away on their own after a few days.

Therefore, side effects that are common and mild or moderate are a good sign: they indicate that the vaccine is working. However, not experiencing side effects does not mean that the vaccine is not effective. In other words, each person will have a different reaction after receiving the vaccine.


Common side effects after receiving the COVID-19 vaccine

Like any vaccine, the COVID-19 vaccine can cause side effects, most of which are mild or moderate and go away within a few days. According to the results of clinical trials, more serious or prolonged side effects may occur. Vaccinations must be continuously monitored for side effects.

The reported side effects of the COVID-19 vaccine are mostly mild to moderate and go away after a few days. Typical side effects include pain at the injection site, fever, fatigue, headache, muscle aches, chills, and diarrhea. The likelihood of any side effects after vaccination varies depending on the specific vaccine.

Less common side effects after COVID-19 vaccination

After vaccination, the recipient is asked to stay at the vaccination site for 15–30 minutes so that health care workers can be present immediately in case of any immediate reactions. The recipient should notify their local health care provider if they experience any unwanted side effects or other health problems - such as side effects lasting longer than 3 days. Less common side effects reported for some COVID-19 vaccines include severe allergic reactions such as anaphylaxis; however, these reactions are extremely rare.

Health authorities and the World Health Organization are closely monitoring any unwanted side effects after receiving COVID-19 vaccines.

Long-Term Side Effects of COVID-19 Vaccines

Side effects typically occur within the first few days after vaccination. Since the first mass COVID-19 vaccination program began in early December 2020, hundreds of millions of doses of vaccine have been administered.

There have been concerns that COVID-19 vaccines will expose people to the virus that causes COVID-19. But none of the approved vaccines contain the live virus that causes COVID-19, which means that COVID-19 vaccines cannot expose people to COVID-19.

After vaccination, it usually takes several weeks for the body to build up immunity to the SARS-CoV-2 virus. Therefore, it is entirely possible for a person to become infected with SARS-CoV-2 before or after vaccination and develop COVID-19 because the vaccine has not had enough time to protect the body.

CDC PY (ST)