What Are the Side Effects from Vaccines?
Just like any other medications, vaccines can cause side effects. Most side effects are minor and resolve within a few days. In fact, many reactions (fever, chills, sore muscles, tiredness) show that the vaccine is working to provide immunity from the disease(s) to be prevented. Very rarely, vaccines may cause more serious reactions.
What are minor or mild side effects?
The most frequently occurring side effects are local ones occur that include soreness, redness, or swelling in place that the vaccine was given. These reactions usually go away within a couple days. Other mild side effects are systemic (those that occur throughout the body) such as fever, chills, tiredness, loss of appetite, nausea, diarrhea, headache, muscle or joint pain. These reactions usually go away within a few days and can be managed with acetaminophen or ibuprofen if you are uncomfortable.
Can I have an allergic reaction to a vaccine?
Yes, although allergic reactions are uncommon (one in a million people for many vaccines). An allergic reaction may be to the vaccine or to associated components. Symptoms of the allergic reaction include hives, swelling of the throat or wheezing, dizziness, and difficulty breathing. Your vaccine provider should have medications and other rescue equipment nearby in case of this rare occurrence. If an allergic reaction occurs with vaccine administration, your doctor should investigate the reaction before giving other vaccines. Possible allergic causes can include egg allergy due to reaction with egg protein used in preparation of the vaccine or latex from the vial stopper (packaging).
Can fainting be a side effect of a vaccine?
Fainting episodes have been noted with administration of human papillomavirus, tetanus/diphtheria, and meningococcal vaccines, but can happen with any vaccine (or medical procedure). It is noted most often in teens and young adults and may be related to anxiety or a response to pain. Because of a concern of potential head injury when falling, you should sit for 15 min after vaccinations. Tell the provider if you feel dizzy, have ringing in the ears, or have vision changes.
What is the chance of having a serious reaction?
Serious reactions are unlikely to occur with vaccines. Some adverse effects may be noted after approval as they are so rare as not to be found in number of people in clinical trials. If you feel unwell after receiving a vaccine and your symptoms do not go away, contact your doctor. They can assess if your condition is due to the vaccine or a coincidental time frame.
Summary
Risk from vaccine side effects must be considered against the risks of contracting potentially life-threatening diseases. Talk to your doctor or pharmacist if you have questions about vaccine side effects.