Post-vaccination adverse events in the elderly in the State of Sao Paulo, Brazil, 2015 to 2017

Vaccination is one of the public health measures that has most contributed to decreasing the incidence of vaccine-preventable diseases. However, vaccines can lead to post-vaccination adverse events. This study thus aimed to analyze the prevalence of post-vaccination adverse events in elderly persons, determine the reported post-vaccination adverse events, identify the vaccines that cause post-vaccination adverse events, and verify the post-vaccination adverse events and vaccines that lead to hospitalizations in the State of Sao Paulo, Brazil, from 2015 to 2017. This was a descriptive cross-sectional study with a quantitative approach based on notifications of post-vaccination adverse events recorded in the Information System of the National Immunization Program. The results showed that of the 15,196,080 elderly persons that were immunized, there were 207 reports of post-vaccination adverse events, of which 187 (89%) were non-serious adverse events and 15 (8%) due to immunization errors (IE). The majority of the patients were female (86%), white (49%), and from 60 to 69 years of age (70%). Clinical manifestations featured local reactions at the injection site (84%). There were 131 cases (64%) that evolved to cure without sequelae. Two individuals (2%) were hospitalized due to serious adverse events. The first had received adult diphtheria/tetanus (dT), pneumococcal (Pn23), and influenza vaccines, and the second had received Pn23. The post-vaccination adverse events notifications showed incomplete information. In conclusion, notification of post-vaccination adverse events is essential. Health professionals need to be committed to adequate completion of the notification forms, with health surveillance supervision aimed at quality of care for elderly persons with post-vaccination adverse events.