AstraZeneca lowers the effectiveness rate of the US Covid-19 vaccine trial

AstraZeneca revised the effectiveness rate of its Covid-19 vaccine trial in the United States to 76 percent, while the pharmaceutical group sought to address concerns that it had published incomplete provisional data earlier this week.

Mene Pangalos, executive vice president of AstraZeneca, said that a reevaluation showed that the data was “consistent” with the figures reported earlier, which had a 79 percent effectiveness rate.

The disclosure came after a few painful weeks for AstraZeneca, with the US independent data and security monitoring board, which oversaw its clinical trial, objecting to the initial disclosure of data as potentially misleading. The Anglo-Swedish pharmaceutical group has also fought a tough battle with the EU over allegations that it has failed to meet supply targets.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said this week that the monitoring committee sent a “very tough note” to him and AstraZeneca.

The council was concerned that the provisional data, with a cut-off date in mid-February, would show a more positive rate of effectiveness, writing that it thought the real rate could be between 69 and 74 percent.

In response, AstraZeneca stepped up its analysis, which involved examining each additional case to see if it was really Covid-19.

The latest review “confirms that our Covid-19 vaccine is highly effective in adults, including those 65 and older,” said Pangalos. The jab, developed with the University of Oxford, was also found to be 85 percent effective in older adults, higher than the previously reported figure of 80 percent, and prevented serious illness and hospitalization.

“We are looking forward to submitting our regulatory application for emergency use authorization in the United States and preparing for the launch of millions of doses across America,” said Pangalos.

The US study included more than 32,000 participants, two-thirds of whom received the vaccine and one-third with a placebo. It resulted in 190 cases of symptomatic Covid-19, according to the new analysis, 49 more than accounted for in the initial analysis. There were 14 more cases to be confirmed as Covid-19, which means that the rate of effectiveness may change slightly.

The most complete data still revealed a higher rate of effectiveness than in the study conducted outside the USA, which was used to obtain regulatory approval in the UK and the EU. This trial resulted in an average efficacy rate of 70 percent in preventing symptomatic Covid-19.

The data will be submitted for peer-reviewed publication in the coming weeks.

AstraZeneca is also mired in a conflict with the EU over alleged supply shortages. The company’s low-cost jab was to be an essential part of the bloc’s vaccination efforts, but the relationship turned into accusations and recriminations.

Italy said on Wednesday that it had discovered a stockpile of 29 million doses of the AstraZeneca vaccine at a facility in the country. The company said it was “incorrect” to describe vaccines stored in this way, adding that the doses awaited “quality control” processes.

However, the discovery sparked further recriminations from Brussels, with EU trade commissioner Valdis Dombrovskis saying that the drugmaker was “promising to deliver doses of 30 million, but they are nowhere near that number”.

AstraZeneca said it made its “best efforts” as required by the contract signed with the European Commission last year, and blamed the product’s low yields at a factory in Belgium for the delays.

The company also said this week that the U.S. monitoring board examined concerns about rare blood clots associated with the vaccine with the help of an independent neurologist and found no problems.