No increased risk of serious adverse events after COVID-19 vaccination

A cohort study of the entire population of an Italian province revealed COVID-19 vaccination did not increase the risk of adverse effects including heart attack, stroke, cardiac arrest, myocarditis, pericarditis, or deep vein thrombosis.

From January 2021 to July 2022, the studyPosted in Vaccines, assessed the incidence of potentially vaccine-related serious adverse events based on COVID-19 vaccination status. Investigators pulled data on all deaths and hospitalizations from serious cardiovascular disease, pulmonary embolism and deep vein thrombosis from the National Health System.

This study is currently the only one in the world to follow its participants for more than a year, taking into account the age, sex and clinical risk of vaccinated and unvaccinated patients.

During the 18-month follow-up period, 2,097 people were hospitalized and 5,743 died from serious adverse events potentially related to the vaccine. Notably, those vaccinated against COVID-19 (n=259,821) did not have an increased risk of death from any cause, death unrelated to COVID-19, or serious adverse events potentially related to the vaccine compared to the unvaccinated cohort (n=56494).

These results remained consistent across gender, age, vaccine type, and COVID-19 infection status. They continued to show no variance in Cox models adjusted for age, sex, infection status, and various comorbidities.

“The results obtained clearly show that there was no increased risk of serious diseases in the vaccinees,” said study coordinator Lamberto Manzoli, a medical epidemiologist and professor in the Department of Medical and Surgical Sciences at the University. University of Bologna.

The results also confirmed that people vaccinated against COVID-19 were more protected against the virus than unvaccinated people who recovered from the infection. Receiving even just one dose of any approved COVID-19 vaccine significantly reduced the risk of death and serious adverse events potentially related to the vaccine.

Additionally, there was a higher incidence of monitored diseases (serious cardiovascular disease, pulmonary embolism, deep vein thrombosis) in people who received only one or two doses of a COVID-19 vaccine, compared to those who had received 3 or more doses of vaccine.

“There have been isolated adverse cases, but the safety profile of the vaccines used during the pandemic has been confirmed: it is now important to continue monitoring over a longer period,” Manzoli stressed.