(Sharecast News) - The US part of the phase three trial of the Covid-19 vaccine candidate being developed by AstraZeneca and the University of Oxford remains on hold, pending authorisation for a restart from independent safety monitors and America's health regulator, the Food and Drug Administration.
Anthony Fauci, the top US infectious disease expert reportedly told CNN it was probably only a matter of time before they recommenced, Bloomberg reported.
However, Dr. Avindra Nath, an intramural director at a division of the US National Institutes of Health, told the same broadcaster on Tuesday that "the highest levels of NIH are very concerned".
UK health regulators cleared AstraZeneca and Oxford to restart the trial at the weekend, days after they were paused due to a potential illness among one participant of unknown cause.
That volunteer had since recovered and was no longer hospitalised.
Nonetheless, according to Dr. Nath, "AstraZeneca "need[s] to be more forthcoming with a potential complication of a vaccine which will eventually be given to millions of people," said Nath.
"We would like to see how we can help, but the lack of information makes it difficult to do so."
Nath said the NIH had yet to receive tissue or blood samples from the British volunteer that fell ill and that an investigation by US scientists was "in the planning staged" with the associated studies possibly taking a month or two to conduct.