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LONDON, Dec 17 (Reuters) - Oxford University's COVID-19
vaccine candidate has a better immune response when a two
full-dose regime is used rather than a full-dose followed by a
half-dose booster, the university said on Thursday, citing data
from early trials.
The developers of the vaccine candidate, which has been
licensed to pharmaceuticals company AstraZeneca, have
already published later stage trial results showing higher
efficacy when a half dose is followed by a full dose, compared
to a two full-dose regime. However, more work needs to be done
to affirm that result.
The latest details from the Phase I and 2 clinical trials
released on Thursday made no reference to the
half-dose/full-dose regime, which Oxford has said had been
"unplanned" but approved by regulators.
Once seen as the frontrunner in the development of a
coronavirus vaccine, the British team has been overtaken by U.S.
drugmaker Pfizer, whose shots have been rolled out in
Britain and the United States this month.
Data published earlier from the later Phase 3 trials showed
efficacy was 62% for trial participants given two full doses,
but a more robust 90% for a smaller sub-group given first a
half, then a full dose.
In its statement on Thursday, the university said it had
explored two dosing regimes in early stage trials, a
full-dose/full-dose regime and a full-dose/half-dose regime,
investigated as a possible "dose sparing" strategy.
"The booster doses of the vaccine are both shown to induce
stronger antibody responses than a single dose, the standard
dose/standard dose inducing the best response," the university
said in a statement.
The vaccine "stimulates broad antibody and T cell
functions," it said.
(Reporting by Alistair Smout and Keith Weir
Editing by William James, Mark Heinrich and Frances Kerry)
