"The drug maker AstraZeneca announced on Monday that an early analysis of some of its late-stage clinical trials, conducted in Britain and Brazil, showed that its coronavirus vaccine was 70.4 percent effective, on average, in preventing Covid-19, the latest encouraging sign that vaccines may fulfill their potential as the world’s best hope to help curb a pandemic that has killed more than 1.3 million people.
One particular dosing plan that was tested — giving people a half-dose first and then, a month later, a full dose, rather than two full doses — was 90 percent effective, the researchers said, raising hopes that AstraZeneca could create more vaccine doses using the same supply. Scientists also noted the vaccine could be stored in a standard refrigerator, rather than the intense chill needed with other potential vaccines."
In an early analysis, the drug maker zeroed in on a promising dosing plan for its vaccine.
www.nytimes.com
Following up on this with some new information posted by the NYT today -
Some trial participants only got a partial dose of AstraZeneca’s vaccine. Experts said the company’s spotty disclosures have eroded confidence.
www.nytimes.com
"The announcement this week that a cheap, easy-to-make coronavirus vaccine appeared to be up to 90 percent effective was greeted with jubilation. “Get yourself a vaccaccino,” a British tabloid celebrated, noting that the vaccine, developed by AstraZeneca and the University of Oxford, costs less than a cup of coffee.
But since unveiling the preliminary results, AstraZeneca has acknowledged a key mistake in the vaccine dosage received by some study participants, adding to questions about whether the vaccine’s apparently spectacular efficacy will hold up under additional testing.
Scientists and industry experts said the error and a series of other irregularities and omissions in the way AstraZeneca initially disclosed the data have eroded their confidence in the reliability of the results.
Officials in the United States have noted that the results were not clear. It was the head of the flagship federal vaccine initiative — not the company — who first disclosed that the vaccine’s most promising results did not reflect data from older people.
The upshot, the experts said, is that the odds of regulators in the United States and elsewhere quickly authorizing the emergency use of the AstraZeneca vaccine are declining, an unexpected setback in the global campaign to corral the devastating pandemic."
"In an interview on Wednesday, Menelas Pangalos, the AstraZeneca executive in charge of much of the company’s research and development, defended the company’s handling of the testing and its public disclosures. He said the error in the dosage was made by a contractor, and that, once it was discovered, regulators were immediately notified and signed off on the plan to continue testing the vaccine in different doses.
Asked why AstraZeneca shared some information with Wall Street analysts and some other officials and experts but not with the public, he responded, “I think the best way of reflecting the results is in a peer-reviewed scientific journal, not in a newspaper.”
"AstraZeneca was the third company this month to report encouraging early results on a coronavirus vaccine candidate. At first glance on Monday morning, the results looked promising. Depending on the strength at which the doses were given, the vaccine appeared to be either 90 percent or 62 percent effective. The average efficacy, the developers said, was 70 percent.
Almost immediately, though, there were doubts about the data.
The regimen that appeared to be 90 percent effective was based on participants receiving a half dose of the vaccine followed a month later by a full dose; the less effective version involved a pair of full doses. AstraZeneca disclosed in its initial announcement that fewer than 2,800 participants received the smaller dosing regimen, compared with nearly 8,900 participants who received two full doses.
The biggest questions were, why was there such a large variation in the effectiveness of the vaccine at different doses, and why did a smaller dose appear to produce much better results? AstraZeneca and Oxford researchers said they did not know.
Crucial information was also missing. The company said that the early analysis was based on 131 symptomatic Covid-19 cases that had turned up in study participants. But it did not break down how many cases were found in each group of participants — those who received the half-strength initial dose, the regular-strength initial dose and the placebo.
“The press release raised more questions than it answered,” said John Moore, a professor of microbiology and immunology at Weill Cornell Medical College.
Adding to the confusion, AstraZeneca pooled the results from two differently designed clinical trials in Britain and Brazil, a break from standard practice in reporting the results of drug and vaccine trials."
