Efficacy 95% a week after the second shot. Pfizer says it is only 52% after the first dose but the UK’s Joint Committee on Vaccination and Immunisation (JCVI) says this may rise to 90% after 21 days.
The UK has ordered 40m doses.
Doses Clinical trials involved two doses 21 days apart. The UK is stretching this to 12 weeks.
Efficacy 70.4% 14 days after receiving the second dose. May have up to 90% efficacy when given as a half dose followed by a full dose. No severe disease or hospitalisations in anyone who received the vaccine. There have been concerns it is less effective against the South African variant of the coronavirus.
The UK has ordered 100m doses.
Doses Two, four to 12 weeks apart
Efficacy Phase 3 trial results suggest 94.1%.
The UK has ordered 17m doses, to be delivered in March or April
Doses Two, 28 days apart
Efficacy Phase 3 trials suggest 89.3%.
60m doses ordered by the UK, with distribution expected principally in the second half of the year
Janssen (part of Johnson & Johnson)
Efficacy 72% in preventing mild to moderate cases in US trials but 66% efficacy observed in international trials. 85% efficacy against severe illness, and 100% protection against hospitalisation and death.
30m doses ordered by the UK
Doses: One, making it unique among Covid vaccines with phase 3 results so far