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In the face of rising coronavirus cases, some European countries are considering whether to change adherence and join the UK by vaccinating as many people as possible with a single dose instead of the two administered during clinical trials so far.
This issue has been published since 30 December, when the UK announced its decision to delay the second dose by up to 12 weeks when it approved the Oxford / AstraZeneca vaccine for emergency use. The switch was also applied to the BioNTech / Pfizer jab.
Just this week, Denmark announced its decision to delay the second dose of Pfizer and the next Moderna jabas by up to six weeks. The German health ministry has also confirmed that it will study expanding vaccination coverage with similar dose delays.
Meanwhile, the U.S. federal government is in talks with Moderna about halving the recommended dose of the shot to speed up vaccination efforts.
Scientists are divided. Some argue that the delay can cause more mutations in the virus and make the shot ineffective. Others question whether receptors will remain more vulnerable, noting that it has not been properly proven to allow larger gaps between doses.
The pro-delay camp argues that a broader, albeit slightly weaker, immediate level of protection is better than providing stronger protection to half as many people. UK Deputy Medical Assistant Jonathan Van-Tam insisted on Sunday on this point in the Mail, saying maximizing coverage with the first dose would “save lives”.
Belgium’s top epidemiologist, Pierre Van Damme, also supports the idea of pausing in dosing. Speaking to VRT last week, he said the strategy would quickly provide protection to more people and that “the herd’s immunity would grow at a much faster rate.” (The Belgian Minister of Health, Frank Vandenbroucke, has asked the vaccine working group to look into the possibility of dose delays, but has not yet made a statement, and his spokesman has warned that there is still not enough evidence of movement)
With the reduced supply of vaccines and the new variants of the coronavirus in the UK and South Africa causing the alarm, aggravated by overloaded health systems, some politicians are now siding in the latter field.
The problem: While many public health scientists have developed and supported the UK approach, it lacks the rigor of controlled evidence that the UK is so well-versed.
It is not fully tested
The idea of vaccinating as many people as possible with the Oxford / AstraZeneca vaccine before it was approved for emergency use was first introduced by former Prime Minister Tony Blair in early November. He was quickly rejected by doctors and scientists on the grounds that he would conduct controlled clinical trials that were already underway for these treatments. These studies ultimately eliminate therapeutic winners (dexamethasone) from losers (hydroxychloroquine).
The debate changed even more this week when the British Immunology Society shook hands on Monday. While their statement gave “maximum value to an evidence-based approach to medical decisions,” they called for a “short-term pragmatic approach,” given the “unprecedented situation.” The Society supported the delayed two-dose program, provided the government developed a “robust immune surveillance program.”
Sheila Bird, a former program leader in the MRC Biostatistics Unit at Cambridge University, went one step further. On Monday, in an emailed statement, it called on the UK to randomize standard and delayed dosing programs to compare the effectiveness of both approaches.
“The tests would be good for all these variations, although the data we have show very good protection against a dose of AstraZeneca or Pfizer [vaccines]… The speed and breadth of vaccination is crucial to success, “said Oxford University professor John Bell, who is also a member of the vaccination working group at the University of Oxford. United Kingdom.
Single shot data
In their defense of dose-delaying, the UK’s leading medical agents noted data showing that the short-term efficacy of the vaccine from the first dose is 90% with the BioNTech / Pfizer vaccine and 70% with the Oxford / AstraZeneca vaccine The second dose is likely to be “very important for the duration of protection,” they said in a joint letter dated Dec. 31.
However, some scientists remain concerned about whether the efficacy could decrease beyond the three- and four-week periods indicated for the second doses of the Pfizer and AstraZeneca vaccines, respectively.
Data from the British Society for Immunology on the BioNTech / Pfizer vaccine, for example, show that antibodies and T cells are more effectively neutralized after the second dose. The company also notes that “similarly, the Oxford / AstraZeneca vaccine shows substantial immune differences after the second dose at 28 days.”
They concluded, however, that delaying a second dose by eight weeks “would be unlikely to have a negative effect on the overall immune response after booster.”
Peter English, former editor of the journal Vaccines in Practice and former chair of the Public Health Medicine Committee of the British Medical Association, also laid out the case of the delays. In an opinion on Monday, he wrote that decades of experience with other vaccines have shown that, in any case, “increasing the interval will improve the quality of the booster response.”
Approval of a single dose?
With Johnson & Johnson investigating the issue in an extensive clinical trial, more data on single-dose efficacy and duration of protection will likely come to light by the end of the month.
Like the Oxford / AstraZeneca jab, the J&J vaccine is based on adenovirus viral vector technology. A modified cold virus is used to carry information to cells, telling them to make the antigen from the ear protein in order to build an immune response.
J&J, which has experience with pandemic vaccination following the successful approval and launch of its Ebola vaccine, said in November that while a single-dose vaccine “would have significant benefits, especially in a pandemic environment, ”the company’s vaccine program is also testing two doses in an independent trial.
The first unpublished results of a first-phase clinical trial showed that a single dose is effective in generating enough antibodies in 98% of patients after 29 days, the company said.
Pending positive results, the US drug maker plans to submit global license applications with data to support the single-dose schedule. The European Medicines Agency expects to make a decision in March.
Final obstacle
The UK approach allows the off-label use of both Pfizer and AstraZeneca vaccines, meaning that these blows can be administered outside their authorized indication without consequences. This is possible due to the instructions of the Joint Committee on Vaccination and Vaccination, which offers protection against retaliation.
The same does not apply to any other part of Europe, where countries will use EMA-approved vaccines.
“I don’t think healthcare professionals … in the EU approve or are inclined to promote any off-label use,” said Vincenzo Salvatore, Bonellei Erede’s lawyer and former EMA chief adviser.
“Any changes to [administration] it would require a variation in the marketing authorization, ”the EMA said, Reuters reported,“ as well as more clinical data to support this change. Otherwise, it would be considered “off-label use.” “
Vaccine manufacturers have also advocated clinically approved indications.
“Our Phase 3 clinical trial and US emergency use authorization are associated with 100ug in two doses, separated by 28 days,” a Moderna spokesman said in an email, on the subject of half doses in the US
BioNTech echoed this sentiment in the FT, reiterating that there are no data to support the administration of two doses of its vaccine given more than 21 days apart.
English, who is also a consultant on communicable disease control in the UK, said the benefit of the vaccine committee is that it “sees the population and the needs of the round”. It includes decades of knowledge about vaccines, the immune system and how they interact, “not just according to the tests that were done to get the license.”
He also warned of the deadly risk of limiting the factors affecting these decisions.
“People are divided into those who want explicit, narrow, direct empirical evidence and those who are willing to extrapolate indirect evidence,” he said. “The point is that lives could be lost if we wait for the close direct evidence.”
Charlie Cooper, Hans von der Burchard and Camille Gijs contributed.
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