Source: China – South China Morning PostImmunity wanes six months after three doses of the Sinopharm Covid-19 vaccine are given, but a fourth shot will not provide more protection against the Omicron strain, a study has found.Researchers from Sun Yat-sen University in Guangzhou said their study suggested that “urgent use” of inactivated vaccines – like the Sinopharm one – as a fourth booster shot against variants of concern such as Omicron was “feasible but not ideal”.Recombinant spike protein or mRNA vaccines based on the variants…Read More