Some scientists have asked governments to give individual doses of Covid-19 after preliminary research suggests they appear to provide some degree of protection, although manufacturers recommend two doses. But other scientists warn that inoculation is not enough to confer lasting immunity.
Food and Drug Administration (FDA) analyzes of the Modern and Pfizer vaccines found that a single dose of either provides protection against coronavirus.
The researchers found in phase 3 trials before they were approved by the U.S. regulator in January.
The scientists found that the Pfizer-BioNTech test is 70% effective with one dose, compared to 95% with two.
After approving the Oxford-AstraZeneca vaccine, British regulators said it was about 70 per cent effective in the 12 weeks following the first dose.
With limited supply of vaccines worldwide, these findings raise a key issue for governments and medical professionals: does it make more sense to vaccinate fewer people with both doses for maximum protection or is it better to spread vaccines by inoculating them? more broadly? but less completely?
Some have suggested that governments should aim to give a single dose to as many people as possible, rather than using half of the vaccines currently available in second doses.
Modern “wasn’t shy about proving that a single dose was so effective and they do the math well,” Chris Gill, an infectious disease specialist at Boston University, told WBUR, Boston’s NPR subsidiary.
Consequently, governments should give as many simple doses as possible as soon as possible, Gill argued, “We could save many lives. Now we can give two doses to people, but in the meantime a lot of people who could have received will die. “Isn’t this an example of where, once again, the perfect is the enemy of the good?”
In the UK, where a new, more contagious coronavirus strain is speeding up transmission, former Prime Minister Tony Blair wrote an opinion piece in The Independent on 22 December arguing that the British government should use “all doses available in January as first doses, which means not keeping half for the second dose ”in the hope that“ even the first dose will provide substantial immunity ”.
But others warn that more research is needed and that until then it makes more sense to administer the vaccines in two separate doses as designed.
“If the second dose of vaccine was superfluous, and we knew it [it] did not extend the duration of protection, the principle would be to protect as many people as save as many lives as possible, “Barry Bloom, an epidemiologist at Harvard University, told WBUR.
Pfizer scientists warned on Thursday in a statement that they did not overly trust that a dose would offer enough long-term protection.
“There is no data” to show that protection after the first dose is maintained after 21 days, they wrote.
The administration of a second dose is important because it increases the chances of regaining normal life by giving people lasting immunity, suggested Jean-Daniel Lelièvre, head of the department of immunity and infectious diseases at Henri-Mondor Hospital in Créteil, near Paris. “The purpose of a second dose is to last the immunity and, as things stand, there is no evidence to indicate that a single dose confers the same level of protection,” he told the French newspaper Le Monde.
The French government will continue to give two doses as recommended, Health Minister Olivier Véran told France Info on Saturday. France will follow the manufacturers ’guidelines for administering the Pfizer-BioNTech vaccine, which the French national regulator approved on December 24th. Inoculations began three days later.
“No data” to support UK combination and combination blows
Across the Channel, the British government changed its vaccination guidelines on December 30 to allow the second dose of both Pfizer-BioNTech and Oxford-AstraZeneca spikes to be administered up to 12 weeks after the first, instead of three. weeks as originally planned.
The UK government also said in guidelines published on 31 December that, in rare cases, people could be given a combination of two Covid-19 vaccines, despite the lack of evidence on the scope of the immunity offered by mixing doses.
The two vaccines are to be given in two shots, several weeks apart, but were not designed to be mixed.
However, British health authorities said that if “the same vaccine is not available or if the first product received is unknown, it is reasonable to offer a dose of the product available locally to complete the schedule”.
Mary Ramsay, head of vaccinations at Public Health England, said this would only happen on extremely rare occasions and that the government does not recommend the vaccine mix.
“Every effort should be made to give them the same vaccine, but when that is not possible, it is better to give a second dose of another vaccine than not,” he told Reuters.
Some warned that the new UK guidelines could have been born of despair.
“There’s no data on this idea,” John Moore, a vaccine expert at Cornell University, told the New York Times.
Britain’s health officials “seem to have completely abandoned science now and are just trying to figure out how to get out of a mess,” Moore said.
(FRANCE 24 with REUTERS)