• Less than a week after delivery of a million doses of the AstraZeneca coronavirus vaccine, South Africa suspends its use following a report that the vaccine did not prevent mild-to-moderate illness from the B.1.351 variant in a 2,000-person clinical trial. Because people in the trial were young and unlikely to become severely ill – and since it was small – more research will be needed to see if the vaccine protects against severe illness and death from COVID-19. Source
• Eswatini announces that it will not be using the AstraZeneca coronavirus vaccine. Source
• A pre-print article reports on a 10-person study of people with immunity from a past coronavirus infection; they were vulnerable to reinfection with the B.1.351 variant although a single dose of an mRNA vaccine significantly increased neutralizing antibodies (by 1,000-fold). Source
• A pre-print article reports on a small study of 32 people, comparing responses to the first and second doses of mRNA vaccines among people with immunity from a precious coronavirus infection versus uninfected persons. People with a previous infection had a strong response to the first dose of mRNA vaccine, and a muted response to the second dose, suggesting that it may not be necessary. Source
