Booster doses of the Pfizer and Moderna vaccines offer improved protection against hospitalisations due to Covid-19 variants, new studies show. Data released by the US Centres for Disease Control found that a third dose of either vaccine is more than 90% effective against both the Delta and Omicron variants. The effectiveness of only two doses was found to wane to 57% after six months. According to the CDC study, vaccine effectiveness against hospitalisation after two doses was 90% until six months after the second dose but fell to 81% afterwards. Two weeks after the third dose, however, effectiveness against hospitalisation rose to 94%.
Source : BBC