CHICAGO • A top US scientist overseeing Covid-19 vaccine trials expects a large American study to determine how effective the experimental inoculation from Astra Zeneca is, following perplexing results from other trials released by the company and its partner Oxford University.
AstraZeneca is among the leading developers of Covid-19 vaccines, but interim data released on Nov 23 from trials in Britain and Brazil shows a vastly divergent performance when the vaccine was tested in two different dose combinations.
The company said a small group of trial subjects inadvertently received a half dose followed by a full dose, instead of the planned two full doses. In that group, the vaccine proved to be 90 per cent effective at preventing illness.
But the larger group that received two full doses showed a 62 per cent success rate. Although 62 per cent efficacy is above the benchmark set by regulators to declare a Covid-19 vaccine a success, it pales when compared with efficacy of 95 per cent and 94.1 per cent demonstrated in large trials for vaccines from Pfizer and Moderna, respectively.
A US study of AstraZeneca's vaccine involving about 30,000 volunteers is in the works and should produce data by late January.
"We feel very comfortable that we designed a really good trial in the United States, where everybody's getting boosted in a uniform time, and we know what the dose is," said Dr Larry Corey, co-leader of the US Coronavirus Vaccine Prevention Network, who helped design and is overseeing trials for the US government's Operation Warp Speed programme.
Separately, the US government's top infectious disease expert Dr Anthony Fauci said the Christmas holiday season could pose greater risks than Thanksgiving when it comes to spreading the coronavirus.
Thanksgiving travel and gatherings typically take place for a shorter period of time, while Christmas events may continue through Hanukkah and New Year celebrations, Dr Fauci said, in remarks made at the Milken Institute's Future of Health summit on Monday.
Christmas "extends that vulnerable period by two to three times", Dr Fauci said, and could pave the way for another surge.
California on Monday compelled much of the state to close shop and stay home, and New York ordered hospitals to increase bed capacity by 25 per cent, as the US braced itself for yet another coronavirus surge during the upcoming holidays.
The order from California Governor Gavin Newsom came into effect one day after the state set a record with more than 30,000 new Covid-19 cases, triggered in areas of Southern California where fewer than 15 per cent of intensive care hospital beds remain available.
President-elect Joe Biden has, meanwhile, named California Attorney-General Xavier Becerra as his Health and Human Services secretary, and mostly filled out a team that will lead the incoming administration's response to the coronavirus pandemic.
His selections so far include Dr Vivek Murthy, who is set to return to the role of surgeon general, a job he held under president Barack Obama, while also helping manage the US government response to the coronavirus.
Mr Jeff Zients, one of Mr Biden's transition co-chairs, has been named coordinator of the Covid-19 response and counsellor to the president. Dr Rochelle Walensky, the infectious diseases chief at Massachusetts General Hospital, will be director of the US Centres for Disease Control and Prevention.
REUTERS, BLOOMBERG
