The update is labeled as the primary analysis. In its last report, the company said the figures constituted a “preliminary assessment of the primary analysis.” The new data are based on 190 positive virus cases, up from 141 in the first analysis. Altogether, 32,449 volunteers were in the trial. As additional 14 potential infections are still being studied, efficacy numbers could change slightly. In its updated report, AstraZeneca again did not reveal how many infections were seen in the vaccine group versus the placebo group.

The Anglo-Swedish drugmaker, which is producing the vaccine developed by Oxford University, corrected some of its earlier figures, lowering its estimate of overall efficacy but reporting even higher efficacy in older adults. The new data confirm “our Covid-19 vaccine is highly effective in adults, including those aged 65 years and over," executive vice president of biopharma R&D, Mene Pangalos, said.

The latest count shows that the vaccine was 76% effective at preventing symptomatic coronavirus infections. Its Mar. 22 statement, the company had put the figure at 79%. Among people aged over 65, the new statement showed the shot to be 85% effective, up from 80% in the previous statement. The drugmaker stood by its assessment of 100% efficacy in presenting severe or critical illness or hospitalization.

AstraZeneca said the US study did not identify any "safety concerns related to the vaccine.” Earlier this month, several countries suspended their use of its shot after several cases of unusual blot clots were observed. But after the European Medicines Agency (EMA) said it was safe and effective, all except Denmark resumed administration of the doses. The company has said it plans to apply to the US Food and Drug (FDA) for an Emergency Use Authorization (EUA) in the first half of April.

In the EU, amid a worrying rise in Covid cases, the vaccine rollout continues to be slow. Among other woes, AstraZeneca is barely managing to fill a quarter of its promised doses for the first half of 2021, Meanwhile, squabbles with the UK over who gets the diminished supply eat up valuable time. Commentators say they fear public confidence has been shaken by the delivery problems, the reported severe side effects and the drugmaker’s poor communication.

Ironically, after the clotting cases that mostly affected women under 55 years old, France is now reserving this vaccine for people older. Both France and Germany originally declined to offer it to people over 65, as no one younger than 55 had participated in one of AstraZeneca’s earlier trials. The UK has offered it mainly to those 65 or older. Although not widely publicized, they was also an incidence of clotting in those receiving the vaccine there. The lack of comparative figures complicates conclusions, however.

Author: Dede Williams, Freelance Journalist