Side Effects of Vaccines

The side effects of vaccines range from mild and expected to serious and unpredictable, although it is important to remember that the risks involved in not being vaccinated may be considerably worse. Nevertheless, be informed of the side effects of vaccines to put your mind at ease the next time you or a loved one gets a shot.

Fever and Swelling

• Common side effects of vaccines are fever and swelling. A moderate fever may be troubling but is typically manageable. Swelling and redness at the injection site are not uncommon. Tenderness and soreness without redness or swelling also frequently occur and may persist for several days following vaccination.

Vomiting and Stomach Issues

• Depending on the vaccine, an individual might experience stomach discomfort, which may appear between one and three days after inoculation. Abdominal pain is common after diphtheria and influenza vaccines, even in adults. Stomach discomfort may lead to vomiting or diarrhea.

Cold Symptoms

• Cold or flulike symptoms may occur as a result of vaccination. Many receiving the flu vaccine, for example, experience headaches, congestion, coughing and a sore throat. Other flulike symptoms may be present, such as muscle pain, weakness, chills and headaches. Rashes and dizziness, although not as common, may crop up and are usually not a cause for concern.

Moderate Problems

• Rare side effects can occur after vaccination, and although they are a cause for concern, such symptoms usually subside with time. For example, certain vaccinations may result in a child crying for several hours on end. Seizures, high fever and rashes as a result of an allergic reaction may occur as well. Some patients experience temporary stiffness or immobility in joints as a result of vaccination.

Serious Side Effects

• Serious side effects from vaccines are extremely unlikely but nevertheless can occur. Serious allergic reactions may cause brain damage or paralysis. Long-term seizures and even comas have been reported as side effects of shots like the diphtheria vaccine. If not properly treated, a patient may die after being inoculated with certain vaccines.

When to Contact a Doctor

• Signs of moderate to severe reactions include high fever and behavior changes. Severe allergic reactions may be characterized by difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat, dizziness and swelling of the throat. If an adult or child demonstrates any of these symptoms, contact a doctor immediately.