The new strategy, announced Wednesday by the head of the UK drug regulator, MHRA, means that the interval between doses can be extended to up to 12 weeks, instead of the three weeks previously stipulated.
This sparked a debate among experts, with the British Medical Association (BMA), a body representing doctors in the United Kingdom, criticizing the decision to postpone consultations for very vulnerable patients who are currently awaiting their second injection.
The Pfizer / BioNTech vaccine has been in use in the UK since early December, when the country became the first in the world to approve it, but supplies are limited.
The debate over the vaccination strategy comes as infection rates soar across much of the UK, thanks in part to a new, more infectious variant of the virus. Most of England is now under the most severe level of restrictions to try to limit the spread of the virus.
“This group of very elderly patients is at the greatest risk of death if they contract Covid-19, which is why GPs are so concerned about them. It is grossly and evidently unfair to tens of thousands of our most at risk patients so far to try reschedule your appointments, “said Dr. Richard Vautrey, chairman of the BMA General Practitioners Committee, in a statement on Thursday.
The UK Medical Association has also raised “real and serious concerns” about the new vaccination strategy, warning on Friday that it could undermine the National Health Service’s patient consent process “, as well as fail to follow the science”.
Meanwhile, Pfizer said it had no data to show that just a single dose of its vaccine would provide protection against the disease after more than 21 days.
“The Pfizer and BioNTech Phase 3 study for the Covid-19 vaccine was designed to assess the safety and efficacy of the vaccine after a 2-dose, 21-day schedule,” Pfizer said in a statement on Thursday . “There is no data to show that protection after the first dose is maintained after 21 days.”
“The second dose of the vaccine is probably very important for the duration of protection, and in an appropriate dose range it can further increase the effectiveness of the vaccine,” they said.
“In the short term, the further increase in vaccine efficacy with the second dose is likely to be modest; the vast majority of initial protection from clinical disease occurs after the first dose of the vaccine ”.
‘Terrible impact’ on emotional well-being
BMA warned in its statement that the delay could have a “terrible impact on emotional well-being” for vulnerable and at-risk patients.
“BMA believes that these are patients who have already been promised, by the NHS and local doctors, that they will receive a second dose of the Pfizer vaccination next week; they gave their consent to receive it and, with good reason, hope to have it “, said the BMA.
Vautrey, the president of BMA, told CNN on Friday that health professionals were particularly concerned about the “practicality of doing this so quickly”, with little warning given to doctors about the revised guidelines.
“We were only told on the last day that we hope, next Monday, to change all the appointments we set for next week again … it just wasn’t practical for our practice team to do that in such a short period of time” said Vautrey.
“We wanted the commitments we made to our elderly patients to give the vaccine to be honored, certainly in the coming days.”
Helen Salisbury, a general practice in the English city of Oxford, told the BBC Today program on Friday that her practice had not yet been completed. canceled the second existing appointments next week. This was because, first, she was unable to find any data on immunity after the first dose beyond 21 days when the booster was administered in the trials and, second, because the practice wanted to protect her most vulnerable patients, the elderly and maintain your confidence in the vaccine.
“When you started treating a patient and said, this is the plan, here is an injection, come back in three weeks, it is very important that you have the second injection to be fully protected – and then turn around five minutes later and say no, don’t worry about it, you can get it in 12 weeks, instead of three weeks – I don’t think it’s good enough, actually, “she said.
In their letter, the medical directors said they recognized the operational difficulties and potential problems involved in rescheduling second appointments in the short term.
“However, we are all aware that for every 1,000 people boosted with a second dose of the Covid-19 vaccine in January (which, as a result, will gain marginally in protection against serious illnesses), 1,000 new people cannot have substantial initial protection, which is in most cases likely to increase them from 0% protected to at least 70% protected “, they said.
Pfizer said it did not evaluate different dosing schedules because “most study participants received the second dose within the window specified in the study design.”
In its open letter, the Doctors’ Association UK wrote: “The protection provided by the first dose of the Pfizer vaccine is considerably less, 52.4% compared to 95% if two doses administered three weeks apart.”
Vautrey told CNN that greater assurances would be needed from both UK medical directors and Pfizer in order to give healthcare professionals and patients confidence in the government’s strategy.
“We need Pfizer itself to be confident that this new dosing regimen will provide effective coverage and protection for our patients, particularly our most vulnerable patients,” said Vautrey.
UK regulators have also advised to give the second dose of the recently approved Oxford / AstraZeneca vaccine, which is expected to be launched from Monday, four to 12 weeks later.
USA are also considering spacing jabs
The strategy of extending the interval between the first and second doses of the vaccine is also “being considered” in the United States, said the director of the National Institute of Allergy and Infectious Diseases, Anthony Fauci, on Thursday.
Two vaccines have already been approved for use in the United States, the Pfizer / BioNTech shot and another from Moderna, which requires a second dose 28 days later.
“I still think that, if done correctly, you can take a single dose, reserve doses for the second dose and still get the job done,” said Fauci on NBC’s Today Show, “but there is a lot of discussion about whether or not you want to. spread the initial vaccination by vaccinating more people in the first round. “
Fauci said this could be debated anyway, but a potential problem would be if the person did not receive the second dose in time and there was a latency period.
He said it was known from clinical trials that “the ideal time is to administer in one day and then for Moderna 28 days later and for Pfizer 21 days later, this is what the data tell us is the best way to do that.”
If you want to keep the data, this is how it should be done, he said, “but you can make an argument, and some people do, about stretching doses by giving a single generalized dose and hoping that you will get the second dose. in time to give to individuals. “
UK Prime Minister Boris Johnson issued an optimistic note on vaccines in a speech on New Year’s Eve.
“We still have a tough fight ahead of us for weeks and months because we face a new variant of the disease that requires new surveillance,” he said.
“But with the sunrise tomorrow 2021, we are sure of these vaccines. I believe that 2021 is, above all, the year in which we will end up doing those everyday things that now seem lost in the past, bathed in a pink glow of nostalgia – going to the pub, concerts, theaters, restaurants or just holding hands to our loved ones in the normal way. “
CNN’s Niamh Kennedy and Vasco Cotovio contributed to this report.