Yes. Vaccines, like all medicines, can cause side effects. It is natural to be concerned, but the reality is that most vaccine side effects are mild and go away within a few days.
The most common side effects of vaccines are pain, swelling, redness, or a hard lump where the shot was injected, as well as mild fever, shivering, fatigue, headache, muscle aches, or joint pain.
Children may develop a high fever after vaccination. The risk depends on the type of vaccine and whether the child receives other vaccines on the same day. High fevers can cause seizures (febrile seizures).
This is why experts now recommend separating shots of the MMR vaccine and Varicella vaccines. The combined MMRV vaccine doubles the risk of febrile seizures to 1 in 1,250 children, according to the CDC.
However, it is exceptionally rare for vaccines to cause severe side effects. Approximately one in 1 million vaccines trigger a potentially deadly allergic reaction known as anaphylaxis, usually within a few hours.
The World Health Organization (WHO) studies the side effects of vaccines and publishes detailed fact sheets on the chances of developing side effects from vaccines. Here are a few resources with more information:
- Hepatitis B Vaccine Side Effects
- Hepatitis A Vaccine Side Effects
- Hib Vaccine Side Effects
- HPV Vaccine Side Effects
- Influenza Vaccine Side Effects
- MMR Vaccine Side Effects
- Rotavirus Vaccine Side Effects
- Polio Vaccine Side Effects
- Pneumococcal Vaccine Side Effects
- Varicella Zoster Vaccine Side Effects
Source: Do vaccines have side-effects?