A BAFFLING CONTROVERSY has unfolded over AstraZeneca’s covid-19 vaccine. On the morning of March 22nd, the company announced positive results about the jab’s safety and efficacy from a clinical trial with 32,000 people conducted mostly in America. But late that night the National Institute of Allergy and Infectious Diseases (NIAID), an American government agency that funded the trial, issued a vaguely worded statement that questioned the company’s announcement. AstraZeneca, it said, “may have included outdated information” which “may have provided an incomplete view of the efficacy data”.
Not much clarity has emerged so far, officially. On March 23rd AstraZeneca (which developed its jab with a team at Oxford University) responded that the results in question were from a “pre-specified interim analysis” of data up to February 17th. Such reporting milestones are standard in clinical trials. The company promised to publish more data within 48 hours. A preliminary analysis of that forthcoming data, it said, had found that the results were “consistent” with what it published.
But Anthony Fauci, head of the NIAID, said in a television interview that AstraZeneca appeared to have made an “unforced error”. He said that the company’s omission of some relevant data was “not necessary” because its jab was already “very likely a very good vaccine”.
The NIAID issued its late-night statement in response to a letter it received from the trial’s Data and Safety Monitoring Board (DSMB), an independent group of experts who oversee clinical trials. Normally, the pharmaceutical companies running the trials and the DSMBs sort out discrepancies between their interpretations of the data behind closed doors. Why they failed to do so this time and whether the gap in the numbers is highly consequential is, at the moment, in the realm of speculation. AstraZeneca reported that the jab was 79% effective against covid-19 symptoms, when administered in two shots four weeks apart. According to the Washington Post, the DSMB’s letter to Dr Fauci and other officials said that the efficacy figures the company should have published were between 69% and 74%.
Results from Britain’s mass-vaccination programme show that the jab works well, with the efficacy of the first shot alone around 70% in some studies. Different variants of the virus in America may be muddling the results there. America’s medicines regulator, the Food and Drug Administration, will have the final say on whether the AstraZeneca jab is good enough for use in the country. The agency conducts its own full analysis of the data from clinical trials submitted for its approval.
The one thing that is all but certain is that the fresh controversy will hurt demand for AstraZeneca’s vaccine. The jab’s popularity in Europe took a tumble last week, when many countries paused its use after suspicions about some blood clots linked to the vaccines. A review by the European medicines regulator concluded that the benefits of the jab outweighed any “possible risk” of a rare type of clot (which, though unproven, could not yet be ruled out). Although vaccination has resumed in most countries, fewer Europeans are keen on the AstraZeneca jab. In America, what people think of it may be irrelevant—at least in the short term. On current trends, all American adults will be offered one of the other three jabs approved in the country before the AstraZeneca jab can feasibly be rolled out.
Any damage to the reputation of AstraZeneca’s vaccine could hobble global efforts to bring the pandemic to an end. In most of the world covid-19 vaccines will be in short supply for at least a year. The AstraZeneca jab is one of those already manufactured in vast quantities. It is cheaper and easier to distribute than the other available vaccines. Confusing publicity, even on matters that may be quickly resolved to everyone’s satisfaction, is the last thing it needs.
All our stories relating to the pandemic and the vaccines can be found on our coronavirus hub. You can also listen to The Jab, our new podcast on the race between injections and infections, and find trackers showing the global roll-out of vaccines, excess deaths by country and the virus’s spread across Europe and America.