While the acellular pertussis vaccine is generally well-tolerated, it can cause minor side effects such as redness at the injection site, fatigue, and mild fever. Serious adverse events are rare but may include allergic reactions. The risk of these reactions is significantly lower compared to the older whole-cell vaccines, which had a higher incidence of fever and febrile seizures. The enhanced safety profile makes acellular vaccines suitable for infants and those with previous adverse responses to whole-cell vaccines.
