Some common side effects of the hepatitis A vaccine include swelling and pain at the injection site, nausea, loss of appetite, and headache.

Hepatitis A is an inflammatory infection of the liver. The infection can cause a range of symptoms, such as appetite loss, pain in the abdomen, and nausea.

It may spread through person-to-person contact, for example, through sexual activity or due to improper handwashing. Alternatively, it may spread when someone ingests food or water that contains the virus.

This article explores the potential side effects of the hepatitis A vaccine, who should consider receiving the vaccine, and the benefits of a hepatitis A vaccination.

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In 2020, the Centers for Disease Control and Prevention (CDC) reported 9,952 new cases of hepatitis A but estimated that nearly 19,900 infections may have occurred in the United States. The CDC also stated that vaccination can help prevent transmission of the virus.

The hepatitis A vaccine contains inactive viruses. The vaccination cannot cause a person to develop hepatitis A, but it can cause side effects in some people.

Common side effects

The most common side effect of the hepatitis A vaccine involves soreness at the site of injection. This reaction may present with:

Other common side effects include:

These side effects are typically mild and often go away within 1 to 2 days. If they do not clear on their own, a person should consider contacting a healthcare professional.

Fainting and allergic reactions

The Food and Drug Administration (FDA) also notes that a person may experience fainting due to any vaccination. It recommends healthcare professionals take steps to prevent injury, such as administering the vaccination to someone while they are sitting.

The FDA also notes that some formulations of the vaccine in prefilled syringes have caps that contain latex. This substance can cause an allergic reaction in some people.

In rare cases, a person may experience a severe allergic reaction to the vaccine or ingredients within it. Signs of a serious allergic reaction include:

If a person experiences these or similar symptoms, they should call 911 or go to the emergency room immediately for treatment. A severe allergic reaction can become life threatening.

In the United States, the law requires that vaccine manufacturers and doctors report any allergic or adverse reactions to a national database known as the Vaccine Adverse Event Reporting System (VAERS). This helps the CDC and FDA track and prevent further use of potentially unsafe vaccinations.

The CDC recommends the following people receive a hepatitis A vaccination:

  • children aged 12 to 23 months
  • people living with chronic liver disease
  • children ages 2 to 18 years who are not vaccinated
  • males who engage in sex with other males
  • certain people who are pregnant
  • international travelers
  • anyone with an occupational risk of exposure
  • people who use drugs recreationally
  • individuals experiencing homelessness
  • unvaccinated people in an area of outbreak
  • people adopting a child internationally
  • anyone living with HIV
  • unvaccinated people who have had direct contact with someone with hepatitis A

However, the CDC also recommends that people who have experienced the following should speak with a healthcare professional about whether they should receive the hepatitis A vaccine:

  • a previous reaction to neomycin, which is a type of antibiotic, or yeast
  • an allergic reaction to the first dose
  • a reaction to any of the components of the vaccination

A person with a cold or another mild illness can still receive the vaccine in most cases. However, they may want to let a healthcare professional know in case they recommend rescheduling the vaccination.

Hepatitis A vaccination has helped reduce the total number of cases in the United States. However, outbreaks may still occur in communities or areas with unvaccinated individuals.

The infection can cause a range of symptoms. Children under the age of 6 may not experience any symptoms, with only about 10% globally experiencing jaundice, which involves a yellowing of the skin or eyes.

Adults often experience hepatitis A symptoms, while older adults may be at higher risk of severe outcomes from infection, such as liver failure.

Common symptoms include:

The hepatitis A vaccine may cause a range of mild symptoms, including pain and swelling at the injection site, malaise, nausea, and headache. In rare cases, the vaccine may cause severe allergic reactions.

The CDC recommends that certain people should receive the hepatitis A vaccine, such as all children, people with HIV, and individuals experiencing homelessness.

By receiving the hepatitis A vaccine, people lower their risk of infection, which may involve symptoms such as jaundice, diarrhea, and malaise. Severe infection may cause liver failure.

People should speak with a healthcare professional to know more about the hepatitis A vaccine, including whether they can receive it and its potential side effects.