LONDON, June 28 — A third shot of the Oxford-AstraZeneca Covid-19 vaccine produces a strong immune response, researchers said today, adding there was not yet evidence that such shots were needed, especially given shortages in some countries.
The British government has said it is looking at plans for an autumn vaccine booster campaign, with three-fifths of adults already having received both doses of a Covid vaccine. “We do have to be in a position where we could boost if it turned out that was necessary ... we don’t have any evidence that that is required,” he told reporters.
Studies had previously shown that the shot, invented at Oxford University and licensed to AstraZeneca has higher efficacy when the second dose is delayed to 12 weeks instead of four weeks.