(Bloomberg Opinion) -- Sam Fazeli, a Bloomberg Opinion contributor who covers the pharmaceutical industry for Bloomberg Intelligence, answered questions about the Covid-19 vaccine developed by AstraZeneca Plc and the University of Oxford after authorities in Germany and France recommended it not be given to the elderly based on the latest trial data. Regulators for the U.K. and European Union approved the shot for use by all adults. The conversation has been edited and condensed.
Amid recent tensions over AstraZeneca’s curtailed dose deliveries to the EU, and despite the European drug regulator suggesting approval of the vaccine for everyone 18 and older, some of the EU’s countries have recommended against using the vaccine in people 65 and over. Why?
This decision seems to be based on phase III trial data that AstraZeneca reported. In the trial, 88% of the subjects were 18 to 55 years old, with only 668 older than 65 with two doses. So there were never enough elderly subjects in the trial to judge the efficacy of the vaccine in that age group. Based on this data, it’s logical that Germany, France and some others would be reluctant to recommend the shot for the elderly. The problem going down this road is that based on this same logic, there aren’t really enough data points to justify use of the vaccine for the 55-to-69 cohort either. So for me a bigger question is, why haven’t these national health-care bodies recommended the same limitations for this slightly younger age group as well?
The U.K. regulators took a different path. What made them comfortable it was acceptable for the elderly?
British authorities used data from early-phase trials of the vaccine that showed it to be as immunogenic in the older population as in the younger ones. The U.K. regulator took the view that this is sufficient evidence that the vaccine will work similarly in older people. Also, the latest analysis of the Astra-Oxford trial data suggests older people do mount a reasonable immune response, though up to a third lower than younger subjects. But this is not 100% sure because the analysis was not an efficacy analysis — it only looked at immune antibody responses in the laboratory. The issue with that is, we still don’t really know whether antibody responses are the main correlate of protection against the disease. There could be other things at work, such as cellular immunity in the form of T-cells. So the U.K. has taken a bit of a gamble on this.
Who is right?
Only time will tell, but looking at the daily number of U.K. cases in people older than 80, there are tentative signs that the vaccine is working. The risk the U.K. is taking is that its strategy may not give older people a strong enough immunity to get an effective protection against the latest variants of the virus. It’s also possible that the protection wanes over time.
What is the data on other vaccines and the elderly?
The shots developed by Pfizer Inc.-BioNTech SE and Moderna Inc. appear to be effective regardless of age. Details from the Johnson & Johnson and Novavax Inc. vaccines aren’t out yet, but at least based on their commentary the shots seem to be effective in older people. Novavax only has early interim data, though.
What is Astra doing or what can it do to make regulators more comfortable with recommending its shot for all age groups?
Simply put, AstraZeneca needs to show more data. It can get this from analyzing the emergent data in the U.K. among the vaccinated. This data will be useful given that EU approval is similar to the U.K.’s in recommending a 12-week dosing interval between the first and second dose. Astra also can get more robust data from its U.S. trial, which should report very soon, but this may actually backfire. We may discover that many older subjects there dropped out of the trial as they became eligible for the Pfizer-BioNTech and Moderna vaccines, which are now being widely distributed. The U.S. trial also may show lower efficacy in general if the latest data from the Astra-Oxford group is right in showing a much lower efficacy of 54.9% in people who had two shots less than six weeks apart — the regimen being followed in the U.S. — compared with 82.4% in those who received doses 12 weeks or more apart.
One related question: What about the recent spate of deaths in Norway that appeared to be related to the Pfizer-BioNTech vaccine, among very old, or even terminally ill, people. Does this mean some older people may be too frail to get the shots?
No. The Norway news was based on anecdotal analysis. Looking at emerging U.S. data from the U.S. Centers for Disease Control and Prevention, there is currently no signal that would suggest an imbalance of death in the nearly 1.3 million people vaccinated in long-term care facilities. Another study from the Genesis Skilled Nursing Facilities in the U.S. found that among 7,000 subjects inoculated by Dec. 31, there was actually a lower mortality rate than among the unvaccinated.
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