A latest Oxford University study found that a third booster dose of the Oxford-AstraZeneca COVID-19 vaccine produces a strong immune response. The researchers also found that a third dose of the vaccine increases antibody and T-cell immune responses, and if the second dose can be delayed up to 45 weeks, it also lead to an enhanced immune response.
The findings were released in a preprint, and the study looked at 30 participants who received a late second dose and 90 who received a third dose, all of whom were under 55. The researchers added that there was not yet evidence that such shots were needed, especially given shortages in some countries, the Reuters reported.
Andrew Pollard, director of the Oxford Vaccine Group, said that the evidence from the study suggests that the vaccine protects against current variants for a sustained period of time meant that such a booster may not be needed.
“We do have to be in a position where we could boost if it turned out that was necessary … (but) we don’t have any evidence that that is required. At this point with a high level of protection in the UK population and no evidence of that being lost, to give third doses now in the UK whilst other countries have zero doses is not acceptable.”
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.