- 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.
- 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 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 vaccine is currently licensed for use in the UK, US, Canada, and Europe. It is given in two doses, 21 days apart.
Pfizer’s trial data shows the vaccine to be 95% effective at protecting against COVID-19 after two doses. A single shot was about 52% effective at preventing COVID-19 in the time until trial volunteers got their second shot. But six days after the second shot, the efficacy rate was found to be 90.5%. Since it takes some time for the shots to take effect, some experts think this may mean the single shot is more effective than we know.
However, there is a debate over whether it would be more efficient to roll out a single shot first, and then worry about the second dose later.
The logistics of giving everyone two doses are daunting:
- Prioritisation takes time: All countries have had to prioritise who gets it first. There are also logistical challenges â€” Pfizer’s vaccine has to be stored at very cold temperatures, for example. So far, 740,000 people have been injected with their first dose of Pfizer’s vaccine, according to Our World in Data on Wednesday.
- It takes months: The current UK strategy, developed with the Joint Committee on Vaccination and Immunization, puts those most at risk of severe COVID-19 first in line â€” older people and healthcare workers. But it could be months before the entire population is immunized.
That’s why Blair suggested using all available vaccine stock to immunize people with their first dose, rather than giving people both shots. (His suggestion is part of a multi-part plan that he drew up, which also urges the UK government to prepare controversial health passports.)
Professor David Salisbury, former head of immunization at the Department of Health, endorsed the idea in an interview with BBC Radio 4 on Wednesday.
“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,” Salisbury said, citing the 90.4% efficacy figure.
He acknowledged, however, that the same guidance would not apply to AstraZeneca’s COVID-19 vaccine, which could be UK-approved imminently, because the efficacy of the full two doses is far lower for that vaccine, at around 60%.
Too risky? Or good sense?
University of Oxford professor Peter Horby, chair of the UK government’s New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) 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, The Telegraph reported.
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,” though it’s 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.
Editors note: This story has been updated to include additional Pfizer trial data about efficacy rates after the first dose.