Just out: COVID-19 vaccine trials primarily assess prevention of virologically confirmed disease; NOT infection or transmission. An “effective” vax confers protection from disease but might not reduce spread...1/5 https://twitter.com/thelancet/status/1308175424019730434

Immunological correlates of protection still unclear, as are prevalence and duration of neutralising Ab response. Important to use live virus neutralisation assays, not just pseudotypes or ELISA...2/5

Vaccine hesitancy, complicated by national partisan politics and geopolitics, can lead to unpredictable population impact...3/5

No country will be truly protected until virtually the entire world is...4/5

First generation vaccines very much needed BUT they are only one tool of many in the overall response. Unlikely to be the ultimate silver bullet many are expecting...5/5