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Faced with the rising incidence of coronavirus, some European countries are considering whether they want to change and together with the UK will vaccinate as many people as possible with just one dose instead of the two administered so far during clinical trials.
This issue has been announced directly since December 30, when the UK announced its decision to delay the second doses by up to 12 weeks when the Oxford / AstraZeneca vaccine was approved for emergency use. The switch was also applied to the BioNTech / Pfizer plug.
Just this week, Denmark announced its decision to delay the second dose of the Pfizer and the upcoming Moderna jabs by six weeks. The German Ministry of Health has also confirmed that vaccination coverage is increased by similar dose delays.
Meanwhile, the US federal government is in talks with Moderna about halving the recommended dose to speed up the immunization efforts.
Scientists are divided. Some believe that the delay could cause further virus mutations and make the shot ineffective. Others question whether the recipients will be more vulnerable, pointing out that allowing larger gaps between doses has not been properly tested.
The camp for the delay argues that an immediate level of broader, if slightly weaker, protection is better than offering half as many people better. UK deputy chief executive Jonathan Van-Tam made the point in the Mail on Sunday, saying the maximum coverage with the first dose would save lives.
Belgium’s leading epidemiologist, Pierre Van Damme, also supports the idea of interrupted dosing. He spoke to broadcaster VRT last week, saying that the strategy would quickly protect more people, and that herd immunity would grow much faster. “The Belgian Minister of Health, Frank Vandenbroucke, has asked the vaccination task team to investigate the possibility of delays between doses, but has not yet made a statement. His spokesman warns that there is still not enough evidence for the move. not.)
With the vaccination of the vaccine and the new coronavirus varieties in the UK and South Africa causing alarm – exacerbated by overloaded health systems – some politicians are now joining the latter camp.
The catch: Although the UK approach is developed and supported by many public health scientists, it does not have the rigor of controlled trials, but the UK is so well acquainted with.
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 put forward by former Prime Minister Tony Blair in early November. It was quickly rejected by doctors and scientists on the grounds that it would be a nuisance over controlled clinical trials already underway for these treatments. Such studies eventually remove therapeutic winners (dexamethasone) from losers (hydroxychloroquine).
The debate shifted further this week when the British Society for Immunology shook hands on Monday. Although their statement ” laid an extreme value on an evidence-based approach to medical decisions ”, they called for a ‘short-term pragmatic approach’ given the ‘unprecedented situation’. The Association supports the delayed two-dose schedule – provided the government develops a ‘robust immune monitoring program’.
Sheila Bird, former program leader at the University of Cambridge’s MRC Biostatistics Unit, has gone a step further. In an email statement on Monday, she called on the UK to randomize standard and delayed dosing schedules to compare the effectiveness of both approaches.
“Trials will be good for all these variations, although the data we have shows very good protection against one dose of AstraZeneca or Pfizer. [vaccines]… The speed and breadth of vaccination is crucial to success, ‘said Professor John Bell of Oxford University, who is also a member of the UK’s vaccination task force, in an email.
Single shot data
In response to the delay in dosing, the chief medical officers of the United Kingdom pointed to data showing that the efficacy of short-term vaccine from the first dose is about 90% with the BioNTech / Pfizer vaccine and about 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 31 December.
However, some scientists remain concerned about whether the efficacy may be longer than the indicated periods of three and four weeks for second-dose Pfizer and AstraZeneca, 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 association also notes that ‘the Oxford / AstraZeneca vaccine also shows a significant immunological difference after the second dose at 28 days.’
However, they concluded that postponing a second dose by eight weeks “is unlikely to have a negative effect on the immune response after the boost.”
Peter English, former editor of the journal Vaccines in Practice and former chairman of the British Health Association’s Public Health Medicine Committee, also set out the case for delays. In a report Monday, he wrote that decades of experience with other vaccines had shown that, if anything, “increasing the interval would improve the quality of the booster response.”
Approved single dose coming?
With Johnson & Johnson investigating the question in a major clinical trial, more data on the effectiveness of single doses and the duration of protection are likely to come to light at the end of the month.
Like the Oxford / AstraZeneca jab, the J&J vaccine is based on adenovirus viral vector technology. It uses a modified cold virus to enter information into the cells, saying they need to make the protein antigen to build an immune response.
J&J, which has experience with vaccination against pandemic after the successful approval and launch of the Ebola vaccine, said in November that although a single-dose vaccine “will have significant benefits, especially in a pandemic,” the company tests ‘s vaccine program also two doses in a separate trial.
Unpublished early results from a clinical trial in the first phase showed that a single dose is effective at generating sufficient antibodies in 98 percent of patients after 29 days, the company said.
In anticipation of positive results, the US drugmaker plans to submit worldwide licenses, with data supporting the single-dose schedule. The European Medicines Agency hopes to reach a decision in March.
Final hurdles
The UK approach allows the use of the Pfizer and AstraZeneca vaccines outside the label, which means that these jabs can be administered without consequences. This is possible as a result of instructions from the Joint Committee on Vaccination and Immunization, which provides protection against retaliation.
The same is not true elsewhere in Europe, where countries will use the EMA-approved vaccines.
“I do not think healthcare professionals … in the EU would endorse or otherwise be inclined to promote any form of outside brand use,” said Vincenzo Salvatore, a lawyer at Bonellei Erede and former EMA chief executive. .
“Any change to [administration] a deviation from marketing authorization would be required, ‘says the EMA, as reported by Reuters,’ as well as more clinical data to support such a change. Otherwise, it is considered ‘off-label use’.
Vaccine manufacturers have also defended clinically approved indications.
“Our Phase 3 clinical trial and U.S. emergency permits relate to 100 doses with two doses, 28 days apart,” a Moderna spokesman said in an email on the subject of half-doses in the US
BioNTech reiterated this sentiment in the FT and reiterated that no data exist to support the administration of two doses of the vaccine given for more than 21 days apart.
Engels, who is also a consultant for the control of communicable diseases in the UK, said the benefit of the vaccination committee is that it ‘considers the population and needs around’. It contains decades of knowledge about vaccines, the immune system and its action – “not just according to trials done to get the license.”
He also warned of the deadly risk of limiting the factors influencing these decisions.
“People divide into people who want explicit, narrow, direct empirical evidence and those who are willing to bring in extrapolation from indirect evidence,” he said. “The issue is that lives can be lost if we wait for the close evidence.”
Charlie Cooper, Hans von der Burchard and Camille Gijs reported.
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