COVID-19 vaccine side effects (and how to alleviate them)

The appearance of reactions after taking the COVID-19 vaccine is completely normal and happens due to the natural response of the immune system, which produces antibodies to fight the substance that was injected. It is this response that makes it possible to create immunity, since the antibodies produced are the same ones that, in the case of a real infection by COVID-19, will fight the virus.

Reactions to the vaccine usually appear within the first 24 hours and the most common are:

• Pain, swelling and/or redness at the injection site;
• Headache;
• Fever and chills;
• Feeling tired;
• Muscle and/or joint pain.

These reactions can last for 2 to 3 days. In the case of vaccines that require more than one dose, general reactions such as fever, headache and muscle pain are more frequent after the second dose, while reactions of pain and swelling in the arm can occur at all doses. See how many doses are needed for each vaccine.

Vaccination is the best way to protect against a serious infection with COVID-19 and, therefore, should be carried out despite causing some adverse reactions. Non-vaccination does not cause any type of reaction, but neither does it protect against the coronavirus, nor does it decrease the chances of a serious infection that can be life-threatening.

How to relieve vaccine reactions

Although COVID-19 vaccine reactions can be a little uncomfortable and affect the vaccinated person's daily life, there are some ways to alleviate them:

1. Pain, swelling and redness at the injection site

To relieve these symptoms, just apply some ice (covered with a clean cloth) on the spot for 10 to 15 minutes, several times a day. This will reduce the inflammation in the area, relieving the discomfort.

It is also important to avoid straining the vaccinated arm, such as lifting weights, especially in the first 2 days.

2. Headache and fever

To relieve headache and fever it is important to rest. However, some natural techniques can help, such as placing a cloth dampened with cold water on the forehead, avoiding wearing very hot clothes and drinking ginger or valerian tea, for example. Check out a list of the main teas to relieve headache and fever.

In addition, and with the guidance of a he alth professional, paracetamol can also be taken every 8 hours. This is an antipyretic remedy that allows you to lower your body temperature, fighting fever.

In case the fever lasts more than 2 days or if it does not improve with the use of medication, it is important to go to the hospital to identify the possible cause, initiating the appropriate treatment.

3. Muscle or joint pain and tiredness

The best way to recover from fatigue and relieve muscle and/or joint pain is to rest as much as possible, avoiding efforts such as lifting weights, cleaning the house or working out, for example.

It is also important to ensure proper hydration and nutrition of the body, drinking plenty of fluids and eating a balanced diet. Liquids can be water, teas, coconut water or natural juices. See what to eat to fight fatigue.

Possible severe reactions

Serious reactions to the COVID-19 vaccine are very rare, but they mostly happen in people who have a history of a severe reaction after taking any other type of vaccine.

These reactions can appear soon after vaccination or up to 4 weeks:

• Severe allergic reaction, usually within 30 minutes after vaccination;
• Formation of clots, which can cause thrombosis;
• Inflammation of the heart.

Although they are very rare, these reactions must be identified as soon as possible, so that they can be treated correctly, avoiding the appearance of sequelae.

In case of symptoms such as feeling short of breath, swelling of the face, severe headache, chest pain or swelling in the legs, it is important to seek medical help.

What causes vaccine reactions?

Reactions that appear after vaccination are a result of the normal response of the immune system to the substance that was injected. This substance varies according to the type of vaccine, but it is always a harmless material, capable of imitating the coronavirus, stimulating the immune response. When this happens, the body produces antibodies that will be "on hold" in case the real coronavirus enters the body. See more about how vaccines work, their effectiveness and safety.

It is common for reactions to be more intense after the second dose of the vaccine as the body already has reserve antibodies that were produced after the first dose. These antibodies act faster and more forcefully against the injected substance.

What does it mean if there are no reactions to the vaccine?

Not having reactions or having very mild side effects does not mean that you do not have immunity against the virus. This is because the intensity of the reactions is related to the way each immune system responds to the vaccine and not to the strength of the immunity conferred.

The only way to know whether or not you have immunity against COVID-19 is to perform a blood test for IgG and IgM antibodies. Learn more about testing for COVID-19.

When to go to the hospital

It is important to go to the hospital whenever there is a suspicion of a serious reaction to the vaccine. In addition, medical help should be sought whenever:

• Fever does not decrease or persists for more than 3 days;
• Swelling and pain in the arm do not improve after 3 days;
• Other symptoms suggestive of COVID-19 appear, such as severe coughing, feeling short of breath, or loss of smell.

The vaccine is not capable of causing COVID-19, however, some people may come into contact with the virus a few days before, or shortly after, vaccination. In these cases, vaccine immunity is not yet active and, therefore, they may end up developing COVID-19. The effectiveness of the vaccine is only guaranteed 14 days after the last dose. See other common questions about the COVID-19 vaccine.