Early data show that two doses of the Oxford / AstraZeneca vaccine resulted in a good immune response

LONDON (Reuters) – Oxford University COVID-19 vaccine candidate has a better immune response when a full two-dose regimen is used instead of a full-dose followed by a half-dose booster, the university said Thursday, citing the data from the beginning of the tests.

Developers of the candidate vaccine, which has been licensed to pharmaceutical company AstraZeneca, have already published the results of the phased trials showing greater efficacy when a half dose is followed by a full dose, compared to a two-dose regimen. complete. However, more work needs to be done to affirm this result.

The latest details of the Phase I and 2 clinical trials released Thursday made no reference to the half-dose / full-dose regimen, which Oxford said was “unplanned” but approved by regulators.

Once seen as the lead in developing a coronavirus vaccine, the UK team was overtaken by US pharmaceutical manufacturer Pfizer, whose shots were launched in Britain and the US this month.

Previously published data from subsequent Phase 3 studies showed efficacy was 62% for study participants who were given two full doses, but 90% more robust for a smaller subgroup, who were half was given first, then a full dose.

In its statement on Thursday, the university said it explored two dosing regimens in the early stages of trials, a full-dose / full-dose regimen and a full-dose / half-dose regimen, studied as a possible “savings” strategy. of the dose “.

“The booster doses of the vaccine have both been shown to induce stronger antibody responses than a single dose, the standard dose / standard dose that induces the best response,” the university said in a statement.

The vaccine “stimulates extensive antibody and T cell functions,” he said.

Reporting by Alistair Smout and Keith Weir; Editing by William James, Mark Heinrich and Frances Kerry