A long interval between first and second doses of the AstraZeneca vaccine does not compromise the immune response against COVID-19, while a third dose could be used as an effective booster, a new study released on Monday by the University of Oxford showed
LONDON (Pakistan Point News / Sputnik - 28th June, 2021) A long interval between first and second doses of the AstraZeneca vaccine does not compromise the immune response against COVID-19, while a third dose could be used as an effective booster, a new study released on Monday by the University of Oxford showed.
According to the preprint results which have yet to be pre-reviewed, researchers found that if administered more than six months after the second shot, the third jab raises the number of antibodies within the blood back to the same levels seen in the wake of double-dose vaccination.
They also recorded an increased immune response against the Alpha, Beta and Delta variants first identified in the UK, South Africa and India, respectively.
Teresa Lambe, lead senior author of the study conducted at the Jenner Institute at Oxford, said results were "very encouraging" in case a third dose is needed.
"It is not known if booster jabs will be needed due to waning immunity or to augment immunity against variants of concern, but here we show that a third dose of ChAdOx1 nCoV-19 [scientific name of the AstraZeneca/Oxford vaccine] is well tolerated and significantly boosts the antibody response," she said.
Andrew Pollard, head of the Oxford Vaccine Group, agreed with his colleague that it is not yet known whether people will need a booster shot in the autumn but stressed the new data shows the existing vaccine could be effective.
Pollard also noted that the fact that a delayed second dose does not compromise the immune response even if it is administered up to 45 weeks later was good news to countries which are concern about limited vaccine availability.
"This should come as reassuring news to countries with lower supplies of the vaccine, who may be concerned about delays in providing second doses to their populations. There is an excellent response to a second dose, even after a 10-month delay from the first," he said.
The use of the AstraZeneca/Oxford vaccine has been marred by numerous reports of rare blood clots following injection, but health authorities claim the risk is very small compared to not being immunized against COVID-19.
