China’s COVID vaccines have been used wiidely but immunity is now waning

China’s CoronaVac and Sinopharm vaccines account for almost half of the 7.3 billion COVID-19 vaccine doses delivered globally, and have been enormously important in fighting the pandemic, particularly in less wealthy nations.

But as the doses mount, so have the data, with studies suggesting that the immunity from two doses of either vaccine wanes rapidly, and the protection offered to older people is limited. This week the World Health Organization announced advice from its Strategic Advisory Group of Experts on Immunization (SAGE) that people over 60 should receive a third dose of the same or another vaccine to ensure sufficient protection. ...