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- Ex-British prime minister Tony Blair said on Wednesday that the government should give people one shot of the COVID-19 vaccine instead of two, so people can be immunized more quickly to curb the spread coronavirus.
- One dose has a 91% effectiveness rate. The second dose raises the rate to 95%.
- Professor David Salisbury, former head of Immunization at the UK Department of Health, backed the idea: “You are only gaining 4% [extra protection] for giving the second dose,” he said.
- Some scientists said Blair’s idea was too risky, given the minimal trial data on how well the vaccines work with a single dose.
- The UK government is looking into the option of one dose, an unnamed source told The Telegraph.
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The British government is in talks with the UK medicines regulator after former UK prime minister Tony Blair called for the government to give everyone a single shot of the vaccine instead of the recommended two doses, according to The Telegraph.
Pharma giant Pfizer’s shot is the vaccine currently licensed for use in the UK, US, Canada and Europe. It is legally approved to be given in two doses, 21 days apart.
However, there is a debate over whether it would be more efficient to roll out a single-dose shot first, and then worry about the second recommended dose later.
The logistics of giving everyone two doses, sequentially, are daunting:
- Prioritization takes time: All countries have had to prioritize who gets it first. There are also logistical challenges – Pfizer’s vaccine has to be stored at very cold temperatures, for example. Seven-hundred-and-forty-thousand people have been injected with their first dose of Pfizer’s vaccine, and more than 2.4 million people have been immunized worldwide, according to Our World in Data on Wednesday.
- It takes months: The current UK strategy, developed with the Joint Committee on Vaccination and Immunisation, puts those most at risk of severe COVID-19 first in line – older people and healthcare workers. But it could be months before the entire population is immunized.
To speed up the process, Blair said that instead of giving people two shots, all available vaccine stock should be used to immunize people with their first dose, rather than giving people already immunized their second. (His suggestion is part of a multi-part plan that he has drawn up, that also urges the UK government to prepare controversial health passports.)
Pfizer has said the vaccine was 95% effective at protecting against COVID-19, 28 days after the first dose, when two doses were given in trials.
But Professor David Salisbury, former head of immunization at the Department of Health - speaking on BBC Radio 4 on Wednesday - noted that a single dose can also be highly effective.
"You give one dose you get 91% [protection]. You give two doses and you get 95%. You are only gaining 4% for giving the second dose," Salisbury explained.
"With current circumstances, I would strongly urge you to use as many first doses as you possibly can for risk groups and only after you have done all of that, come back with second doses," he added.
He did, however, acknowledge that the same principles do not apply to AstraZeneca's COVID-19 vaccine - that could be UK-approved imminently - because the efficacy of two doses is lower, at 60%.
Too risky? Or good sense?
University of Oxford's Professor Peter Horby, the UK government's New and Emerging Respiratory Virus Threats Advisory Group - NERVTAG chair - told the Commons select committee on Wednesday that you can't assume one dose is as good as two doses. The current data favours two doses. He also said that we don't know how much of the population has to be immunized with one dose to reduce the spread of virus.
Professor Wendy Barclay, head of the Department of Infectious Disease at Imperial College London and NERVTAG member said that the idea was interesting, but "too risky".
"To change at this point, one would have to see a lot more analysis of clinical trial data," Barclay said.
However, there are experts that see some benefits to Blair's plan. "Live conversations" are now going on between the UK government and regulator, per The Telegraph.
Professor Peter Openshaw, professor of experimental medicine at Imperial College, London, told the Telegraph on Wednesday that the move would go against normal practice but did make "good sense", but it was unclear how long immunity would last if people are given just one dose.
"It does make sense immunologically that a highly effective vaccine might only need one dose, but the durability of the protection is unpredictable," Openshaw said.
"A booster might be needed subsequently to enhance responses and make them last longer," he added.