Real-time monitoring of the effectiveness of six COVID-19 vaccines in Hungary in 2021 using the screening method

Several studies have reported a waning of the effectiveness of COVID-19 vaccines. We report real-life vaccine effectiveness in Hungary, estimated with the screening method, in 2021, i.e., covering the dominance of both the Alpha and the Delta variant, and including the booster roll-out. Hungary is in the unique position to use six different vaccines (including the Sputnik V and Sinopharm vaccines, for which limited evidence was available prior to the present study) in the same, relatively homogeneous population. All vaccines provided high level of protection initially which declined over time. While the picture is different in each age group, the waning of immunity is apparent for all vaccines and especially in the younger age groups and the Sinopharm, Sputnik-V and AstraZeneca vaccines, which performed similarly. This is clearly reversed by booster doses, more prominent for those vaccines, where recipients were more likely to take the booster dose (which were the aforementioned three vaccines). Booster doses were almost exclusively mRNA vaccines. Overall, two vaccines, Pfizer/BioNTech and Moderna tend to produce the best results in all age groups, and even with waning taken into account.