What are the side effects of the third dose of the COVID-19 vaccine?
Dec 03, 2025
Source: Cainiu Health
Dr. Ren Yi
Introduction
In general, after receiving the third dose of the COVID-19 vaccine, some individuals may experience side effects such as redness, swelling, and pain at the injection site, mild fever, fatigue, headache, dizziness, and muscle aches. Side effects from the third dose are mostly transient, similar to those observed after the first two doses and often milder. It is recommended to maintain a light diet and regular作息 (daily routine) after vaccination.
Generally, after receiving the third dose of the COVID-19 vaccine, some individuals may experience side effects, mainly including redness, swelling, and pain at the injection site, mild fever, fatigue, headache and dizziness, and muscle aches. A detailed analysis is as follows:
1. Redness, swelling, and pain at the injection site: This is the most common local side effect, which typically appears within hours after vaccination. It manifests as redness and slight swelling of the skin at the injection site, accompanied by tenderness or pain when pressed or moved. Symptoms are usually mild and resolve spontaneously within 1–3 days without special treatment.
2. Mild fever: A small number of people may develop a low-grade fever after vaccination, with body temperature generally between 37.3°C and 38°C, lasting for about 1–2 days. Fever is usually a normal response of the immune system. Resting adequately and drinking plenty of warm water can help relieve symptoms; antipyretics should not be used unnecessarily.
3. Fatigue and tiredness: After vaccination, the body's immune system becomes active, which may lead to noticeable fatigue, lack of energy, heavy limbs, and easy exhaustion even after light activity. These symptoms are usually short-lived and recovery is rapid with sufficient sleep.
4. Headache and dizziness: Some recipients may experience mild headaches or dizziness, typically causing only minor discomfort that does not interfere with daily activities. These symptoms may be related to mild stimulation of the nervous system by the vaccine. Avoiding strenuous activity and maintaining emotional stability can help alleviate them.
5. Muscle aches: This often presents as soreness or pain in muscles or joints throughout the body, particularly noticeable in the back, waist, arms, and legs. The pain is usually mild and appears 1–2 days after vaccination. Gentle massage or warm compresses can reduce discomfort, and symptoms generally do not last long.
Side effects from the third dose of the COVID-19 vaccine are mostly transient and similar to those experienced after the first two doses—often even milder. Maintaining a light diet, regular作息 (sleep schedule), and avoiding excessive fatigue after vaccination can help the body smoothly pass through the reaction period.
