LONDON: The second and third dose of the AstraZeneca vaccine increases immunity against Covid-19, a study by Oxford University, which developed Jab with the British-Sweden company, said on Monday.
Intervals up to 45 weeks between the first and second doses of the AstraZeneca vaccine caused an improved immune response, rather than reducing immunity, the research said.
Providing the third dose of JAB more than six months after the second dose also leads to “substantial increase” in antibodies and induces “strong encouragement” to the subject’s immune response, pre-print study, meaning not to be reviewed peer-peer.
“This will come as a convincing news to the countries with lower vaccine supplies, which might be worried about delays in giving the second dose to their population,” said the main investigator of the Oxford trial, Andrew Pollard.
“There is a very good response to the second dose, even after the delay of 10 months from the first.” The researchers said the results for the third dose of astrazeneca were delayed positively, especially as a country with a sophisticated vaccination program considering whether the third booster shot would be asked to extend immunity.
“It is not known whether Jab Booster will be needed because of reduced immunity or to add to the immunity to the variant that is a concern,” said the main senior writer of the study, Teresa Lambe.
He explained that the research showed Jab Astrazeneca “well tolerated and significantly increased antibody response.” Lambe added the results encouraging “if we find that the third dose is needed”.
The development of Jab, which is given in 160 countries, has been praised as a milestone in a pandemic because of the relatively low cost and ease of transportation.
However, trust in Jab, like the vaccine developed by US companies Johnson & Johnson, has been hampered by concerns over relations with blood clots that are very rare but serious in some cases.
A number of countries have suspended the use of vaccines as a result or limiting their use by less risky groups from Covid.
The Oxford study shows that the side effects of vaccines are generally “well tolerated” with “lower side effects incidents after the second and third dose than after the first dose”.