By Jenny Strasburg

LONDON -- The Covid-19 vaccine being developed by the University of Oxford and AstraZeneca PLC was found to be as much as 90% effective in preventing infections without serious side effects in a large clinical trial in the U.K. and Brazil, the partners said Monday.

Efficacy ranged from 62% to 90% depending on dosage given, AstraZeneca and Oxford said.

AstraZeneca said there were no serious safety events related to the vaccine and it was "well tolerated" across different dosing regimens. Late-stage clinical trials of the vaccine are continuing in the U.S. following a pause that spanned most of September and October.

AstraZeneca said it would seek emergency-use authorization from the World Health Organization to distribute the vaccine in low-income countries and prepare regulatory submissions to authorities in countries that have early-approval programs.

Two other leading vaccines have shown to be more than 90% effective in late-stage trials: one from Pfizer Inc. and Germany's BioNtech SE, and the other from Moderna Inc. Pfizer and BioNTech late last week said they asked for approval from the U.S. Food and Drug Administration to permit use of their vaccine.

Write to Jenny Strasburg at jenny.strasburg@wsj.com

(END) Dow Jones Newswires

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