Short-Term Adverse Effects of the Fourth Dose of Vaccination against COVID-19 in Adults over 40 Years of Age.

Booster vaccines are a strategy to mitigate the conditions in the health, social, and economic fields that the COVID-19 pandemic has brought. A series of adverse effects have been observed since the first vaccination. The present investigation aims to describe the short-term adverse effects of the fourth dose against COVID-19 in adults older than 40 from a region of Peru.