COVID-19 vaccines are highly effective also against the Omicron variant

COVID-19 vaccines are highly effective against the most severe symptoms, even against the Omicron variant, and six months after the last dose. This is revealed for the first time in a study published in the journal Vaccines. The study was coordinated by Lamberto Manzoli, a medical epidemiologist and professor at the Department of Medical and Surgical Sciences at the University of Bologna.

The research also involved scientists from the University of Ferrara and the Local Health Authority (ASL) of Pescara and investigated for over a year the effectiveness of coronavirus vaccines on the entire population of an Italian region, Abruzzo. The data collected made it possible to analyze several aspects, including the differences between those vaccinated with two and three doses, the persistence of protection six months after the last dose, the severity and contagiousness of the Omicron variant among both vaccinated and unvaccinated, and the differences between the young and the elderly population.

"Our results first confirm that those who have received two or three doses of vaccine have an 80% to 90% lower risk of hospitalisation or death from COVID-19 than those who are not vaccinated," explains Professor Manzoli. "We have seen that this protection while decreasing, remains high also against the Omicron variant, even six months after the last dose."

Although a 30% reduction in vaccine efficacy emerged six months after the last dose, the risk of serious consequences from COVID-19 remains 70% lower than among the unvaccinated, even among those who received only two doses, both before and after the arrival of the Omicron variant.

In general, the vaccine's protection against SARS-CoV-2 infection was moderate with both two and three doses. However, one should consider that vaccinated persons had fewer restrictions in terms of access to public and private places than unvaccinated persons, and therefore a higher chance of coming into contact with coronavirus.

Finally, looking at age differences, the analysis showed that with the Omicron variant the risks of serious consequences for the under-30s are very limited, even among the unvaccinated.

The study was published in the journal Vaccines and is titled “Effectiveness of COVID-19 Vaccines in the General Population of an Italian Region before and during the Omicron Wave”. The survey was coordinated by Lamberto Manzoli, in collaboration with Cecilia Acuti Martellucci and Maria Elena Flacco from the University of Ferrara, and Graziella Soldato, Giuseppe Di Martino, Roberto Carota and Antonio Caponetti from the ASL of Pescara.