What are the potential adverse effects of the influenza vaccine?

The most common adverse effects of injectable influenza vaccinations in both adults and children are local symptoms. They include pain, swelling, redness and hotness at the injection site.

  • In different data sets, pain, redness and swelling at the injection site has occurred in about one out of four vaccine recipients.
  • Fever is more common in children under the age of 2. In most studies, it occurs in one out of ten vaccine recipients.
  • Skin reactions occur in infants, especially in connection with fever.
  • In very rare cases, joint inflammations, cases of transient reduction in the platelet count or neurological adverse effects have been reported.

The most common side effects of the nasal spray vaccine are a blocked or very runny nose, which occur in more than one out of ten recipients. Rashes occur rarely. 

After the administration of both an injectable and nasal spray vaccine, the following may occur:

  • a mild feeling of illness
  • muscle and joint pain
  • systemic symptoms, including a temperature, fever, irritation, nausea and headache.

Fever and pain medications may be used to treat local symptoms at the injection site, aches and pains, and fever.

Local and systemic symptoms or aches and pains are not contraindications to further vaccinations. Skin reactions are usually also not an obstacle to further vaccinations in following years.

Serious side effects such as a severe allergic reaction, anaphylaxis, are very rare.

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