Which Vaccines Cause Reactions?

last updated on: 03.06.2025 | Medical review by:

Mayara Belli

Nutritionist

We all know the importance of vaccination in children’s lives. But with it also come concerns about side effects or possible reactions considered normal. With that in mind, let’s list the main vaccines that can cause reactions so parents can prepare to reduce symptoms and discomfort. In the first months of life, some vaccines are required as part of the child vaccination schedule. These should be followed strictly and administered at the recommended time; if you have any questions, it is always good to talk to the pediatrician.

Main Diseases, Vaccines, and Reactions

Chickenpox Vaccine: Chickenpox is one of the most common childhood diseases, and it is also one of the most contagious. The most common reactions to the chickenpox vaccine are: fever, redness, rash between 10 to 21 days after receiving the vaccine, and localized, painful inflammation. Although complications related to chickenpox are very rare, the vaccine is extremely important¹. In more severe cases, bacterial infections, pneumonia, and encephalitis may occur. Hepatitis B Vaccine: Hepatitis B is a disease that directly affects the liver and can cause other acute infections. Some reactions to the hepatitis B vaccine include: muscle pain, sensitivity at the injection site, as well as joint pain and fever. The hepatitis B vaccine is very important², as it is a highly contagious disease that can cause serious complications such as: liver cirrhosis, digestive tract hemorrhages, bacterial peritonitis, hepatocellular carcinoma, and the risk that the infection becomes chronic. Polio Vaccine: Polio³ is an infectious disease transmitted from person to person. It is caused by a virus that lives in the intestine, and transmission occurs through the mouth. Younger children who do not strictly follow hygiene habits are at greater risk. The most common reactions to the polio vaccine are: headaches, diarrhea, muscle pain, throat irritation, and vomiting. Pneumococcal Vaccine: Pneumococcus is a bacterium spread through droplets of saliva, which are transmitted when an infected person sneezes or coughs; for this reason, it is highly contagious⁴. Most children who receive the pneumococcal vaccine can have reactions such as: irritability, which is the most common symptom, and in isolated cases, pneumonia, meningitis, fever, and loss of appetite may occur. MMR Vaccine: This vaccine is designed to protect against three diseases: measles, mumps, and rubella. Vaccines with live attenuated viruses should not be administered to children with congenital diseases or deficiencies⁵. Reactions usually appear 7 to 12 days after the vaccine is given. At the injection site, swollen lymph nodes may develop, and the child may have fever, fatigue, and rash. Influenza Vaccine: Influenza is a viral disease transmitted through coughing or sneezing by an infected person⁶. The virus is classified as type A, B, and C. However, only type A and B viruses are associated with the major epidemics that currently occur. After receiving the influenza vaccine, it is common to experience reactions such as: severe pain at the injection site, cough, and headache. In general, the symptoms disappear within about 2 days; if they persist, you should consult a doctor. Rotavirus Vaccine: Rotavirus is a virus that is easily transmitted and very common, especially in children from 6 months to 2 years old, because of their oral phase of putting everything in the mouth, including objects⁷. After the rotavirus vaccine, it is common to have reactions such as: pain at the site, hardening of the injection area, redness, fever, and irritability.

How to Prevent Vaccine Reactions?

Unfortunately it is not possible to prevent vaccine reactions, but with a few tips we can ease the suffering of our babies and children. For example, in the case of redness at the injection site, you can use a cloth and warm water and gently apply it to the site three times a day until the discomfort improves. In case of fever, it is recommended to give an antipyretic within the period and at the dosage indicated by the pediatrician. If the child is ill or showing signs of fever, it is recommended to wait for recovery before administering the vaccine. The use of certain medications can also affect the child’s immunity. If the child is undergoing treatment, you should consult the pediatrician to see if they can have the vaccine or if they should wait until after the treatment. Mixing the vaccine component with some medications can cause complications or even “mask” symptoms. After the vaccines are given, complete observation is necessary. It’s important to note that some children can be allergic to some components of vaccines, so close monitoring is required after each dose is given. If you notice signs of an allergic reaction, seek medical attention immediately. See Also: Childhood Vaccination – Lifelong Protection Photo: StockSnap

References:

1Bricks, L. F., Sato, H. K., & Oselka, G. W. (2006). Vacines against chickenpox and the MMRV vaccine. Jornal de Pediatria, 82, s101-s108.
2Lopes, T. G. S. L., & Schinoni, M. I. (2011). General aspects of hepatitis B.
3Campos, A. L. V. D., Nascimento, D. R. D., & Maranhão, E. (2003). The history of polio in Brazil and its control by immunization. História, Ciências, Saúde-Manguinhos, 10, 573-600.
4 Berezin, E. N., Carvalho, L. H., Lopes, C. R., Sanajotta, A. T., Brandileone, M. C. C., Menegatti, S., ... & Guerra, M. L. (2002). Pneumococcal meningitis in childhood: clinical characteristics, most prevalent serotypes, and prognosis. Jornal de Pediatria, 78, 19-23.
5Portella, B. (2016). MMR vaccine.
6 Petrova, V. N., & Russell, C. A. (2018). The evolution of seasonal influenza viruses. Nature Reviews Microbiology, 16(1), 47-60.
7 Bricks, L. F. (2005). Rotavirus: update on diseases and vaccines. Pediatria (São Paulo), 252-266.

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