The Trump administration doubled its orders from Pfizer and Moderna this month to 200 million doses each. But both vaccines are administered in two doses per person, which means that the US supply will cover only 200 million of the country’s 250 million adults. Authorizing more vaccines for emergency use can immediately increase this stock and also help ensure sufficient vaccine when inoculation is allowed for teenagers and children.
Johnson & Johnson is preparing to release the first data on the effectiveness of its injection, which is administered in a single dose, in January. AstraZeneca may also release more data as early as next month from its final stage tests, officials from Operation Warp Speed of the federal government recently said. (The company said in a statement that “it no longer has updates on the specific US test”).
A pioneer in the global race for vaccines, AstraZeneca has sold more injections worldwide than any other manufacturer. Between agreements with the World Health Organization, the Coalition for Preparation and Innovation for Epidemics and Serum Institute, a mass manufacturer in India, the British pharmaceutical company has promised nearly 1 billion injections to other countries – not including the 300 million it promised to the USA
The AstraZeneca vaccine is much cheaper than others and much easier to ship and store than vaccines like Pfizer, which require deep-frozen freezers or dry ice. This makes it an attractive option for areas of difficult access in the USA, as well as for low-income countries with less advanced infrastructure.
But the prospects for the company’s vaccine are hazy after AstraZeneca reported last month that nearly 3,000 study volunteers in the UK accidentally received a first half-dose. The regimen proved to be 90 percent effective on initial data, outperforming the 62 percent effectiveness of two standard doses. Some vaccine experts think the success of the lowest dose may be a statistical fluke, as 3,000 people are a small slice of the tens of thousands of people enrolled in the company’s tests; others say it can indicate a clearly better option.
AstraZeneca would still have to fully test the lower dosage regimen before applying to the Food and Drug Administration for authorization for emergency use. The agency also requires pharmaceutical companies to follow at least half of the study volunteers for two months after the last dose.
A company spokesman said there was “nothing to be shared about US filing plans at this time”.
But the FDA’s minimum criteria for applying for authorization do not tell the whole story of the value of a vaccine, said Peter Hotez, a virologist and dean of the National School of Tropical Medicine at Baylor College of Medicine.
“Initial effectiveness during the first two months is just one of several aspects that require consideration,” said Hotez, who is also developing a potential injection of coronavirus with partners in India. “Other vaccines may offer advantages in terms of protection durability, tolerability, safety, suitability for children or teenagers, and for that we will require additional vaccines. “
Pfizer and Moderna have only recently begun to study their vaccines in children under 12 years of age, and no manufacturer has started testing even younger children. Regulators also asked for more data on pregnant women and certain risk factors, such as heart disease, diabetes and other diseases that can affect the immune system. Health experts say a vaccine that may work only moderately overall may be better for important subpopulations, such as pregnant women.
And some of the vaccines still in development may be easier to manufacture, transport or administer than the Pfizer and Moderna vaccines.
Both authorized vaccines use relatively new messenger RNA technology to instruct cells to produce a protein found in the virus, which speeds up the body’s immune system. J&J and AstraZeneca use a more traditional method, in which small pieces of DNA from the coronavirus are edited into a weakened version of another virus, called adenovirus. When adenovirus enters cells, they read their DNA and produce a protein found in the coronavirus.
One theory about the dosage confusion of AstraZeneca is that a full dose of the adenovirus elicited a very large immune response – so the body didn’t have time to learn much about the coronavirus it should protect against, said Rasmussen. “It’s still worth having that information, because maybe [AstraZeneca] you can start evaluating this half dose regimen. “
But AstraZeneca’s data could pose a dilemma for the FDA’s independent vaccine advisory panel, which met publicly to discuss each candidate in an attempt to increase transparency and public confidence. The company said the combined results so far of its Phase III tests show that its vaccine is 70 percent effective. But the two dosage regimes tell different stories: 90% is basically comparable to existing vaccines; 62 percent did not.
“You cannot combine data from two different dosing strategies, two different dosing ranges and two different placebo groups,” Paul Offit, a vaccine expert at the University of Pennsylvania who is on the FDA panel of experts, Vaccines and Related Biological Products Advisory Committee.
It also presents a complicated situation for the largest national vaccination plan in history. Although the two authorized vaccines now have nearly identical efficacy and safety profiles and use the same technology, it would be more difficult to justly distribute a more diverse list of vaccines.
“There are obvious ethical questions: if a vaccine is more effective than the others, who gets what, right?” said Philip Landrigan, director of Boston College’s global public health program, who emphasized the importance of clear federal planning if that happens. “Transparency and openness have another benefit besides just ensuring that the system works well – it can persuade people who are reluctant to get the vaccine.”