A third vaccine dose of Pfizer-BioNTech is effective in reducing severe Covid-19-related outcomes compared to individuals who have received two vaccine doses at least five months ago, finds a new study.

The results show that, compared with individuals who received only two doses five months prior, individuals who received three doses of the vaccine (7 days or more after the third dose) had 92 per cent lower risk of severe Covid-19 disease and 81 per cent lower risk of Covid-19-related death.