Vaccines given 44-45 weeks apart observed increasing and prolonging immunity

• A single dose of Chadox1 ncov-19, with a second dose given after a prolonged period, may, therefore, be an effective strategy when vaccine supplies are scarce

Two doses of the Astrazeneca vaccine administered 44-45 weeks apart generated nearly four times the level of antibodies than when the doses were given 8-12 weeks apart, says a report by the Oxford Vaccine Group, the developers of the vaccine, on Monday, the Hindu reported.

According to the Hindu report, antibody levels remained elevated for nearly a year and a third booster dose of the vaccine, given to a subset of volunteers, also significantly boosted antibody levels to twice that after a second dose.

“A single dose of Chadox1 ncov19, with a second dose given after a prolonged period, may, therefore, be an effective strategy when vaccine supplies are scarce in the short term.a third dose results in a further increase in immune responses, including greater neutralisation of variant SARS-COV-2 viruses, and could be used to increase vaccine efficacy against variants in vulnerable populations,” the authors report in a pre-print publication. this means the study is yet to be-reviewed.

A group of vaccine volunteers who got their second dose 15-25 weeks after the first, saw average antibody levels at nearly twice those in the 8-12 week interval, suggesting that lengthening the duration between doses appeared to be boosting antibody count.

Thus, average IGG (immunoglobulin G) levels for 8-12, 15-25, and 44-46 weeks were 923, 1860 and 3738 units respectively, when measured 28 days after the second dose. The volunteers chosen were among those who’d been part of the phase 1/2 and phase 2/3 clinical trials.