What are the adverse reactions after receiving the third dose of the vaccine?
Dec 02, 2025
Source: Cainiu Health
Dr. Li Feng
Introduction
After receiving the third vaccine dose, possible adverse reactions may include local pain, redness, and swelling; mild fever, fatigue, muscle or joint aches; gastrointestinal discomfort; or mild allergic reactions. These are generally temporary and mild in severity, so there is no need for excessive concern. However, if severe allergic reactions, persistent high fever, or difficulty breathing occur, prompt medical attention is recommended. Pain, soreness, or slight swelling at the injection site may also develop.
After receiving the third dose of the vaccine, possible adverse reactions may include local pain and redness at the injection site, mild fever and fatigue, muscle or joint aches, gastrointestinal discomfort, and mild allergic reactions. These are generally temporary and mild in severity, and there is no need for excessive concern. However, if severe allergic reactions, persistent high fever, or difficulty breathing occur, prompt medical attention is recommended.
1. Local pain and swelling: Pain, soreness, or mild redness and swelling at the injection site—sometimes accompanied by a hard lump—are normal responses caused by the vaccine stimulating local tissues. These symptoms typically resolve on their own within 1–2 days.
2. Mild systemic fever and fatigue: A low-grade fever below 38.5°C, along with fatigue or dizziness, may appear within 24–48 hours after vaccination. Symptoms usually last 1–3 days and resolve spontaneously without specific treatment.
3. Muscle and joint aches: Soreness or aching sensations in muscles or joints are related to the immune response triggered by the vaccine. These symptoms are typically mild and short-lived, not interfering with daily activities.
4. Gastrointestinal discomfort: Some individuals may experience mild nausea, bloating, or diarrhea. These transient reactions are likely due to minor stimulation of the gastrointestinal tract by the vaccine and usually resolve quickly with a light diet.
5. Mild allergic reactions: Skin rashes, itching, or mild hives may occur, often representing delayed-type allergic responses. Avoid scratching; symptoms generally subside within a few days.
Remain under observation at the vaccination site for 30 minutes after inoculation. Keep the injection site dry and clean for 24 hours, avoiding contact with water. Maintain a light diet, avoid spicy or irritating foods, drink plenty of fluids, get adequate rest, and refrain from strenuous physical activity to help your body smoothly pass through the period of immune response.
