Breakthrough in the fight against Covid

Clinical trials of Pfizer and BioNTech’s vaccine first began in May, said The New York Times. In experiments “specifically designed to detect warning signs” about safety, scientists tested four versions of the vaccine and proceeded with the one that produced the fewest instances of side-effects such as fever and fatigue. The final

Phase 3 trial – involving more than 43,000 people – then began on 27 July. Half the participants got the vaccine; the other half got a salt water placebo. Scientists then waited for participants to contract Covid-19 to see if the vaccine protected them.

Three months later, 94 of the volunteers had been diagnosed with Covid-19, said Tom Whipple in The Times.

The vast majority of these infected volunteers had been given the placebo: only about eight of them had been given the vaccine. The trial will continue until 164 cases have been confirmed, said Graham Lawton in the New Scientist; but the chances of the verdict on the vaccine’s efficacy changing are now “vanishingly small”, prompting hopes that it could be approved by regulators before the end of the year.

And the Pfizer/BioNTech vaccine isn’t the only one making headway, said Nicola Davis in The Guardian. There are now 11 vaccines in Phase 3 trials – including the one that is being developed by Oxford University and AstraZeneca, of which the UK Government has ordered 100 million doses. Results from that trial, and others, are expected to be released in the coming weeks.