The UK strategy of delaying the second dose of the Covid-19 vaccine was the "right decision", early signs have suggested.
It was announced at the end of last year that the second doses of the vaccines should be given towards the end of 12 weeks, rather than in the previously recommended three to four weeks.
The Government said the decision was taken to prioritise giving the first doses of the vaccine to as many people as possible on the priority list, in an effort to protect the greatest number of at-risk people overall in the shortest time possible.
However, some medical professionals have criticised the delay and the World Health Organisation (WHO) has advised that the second dose of the Pfizer/BioNTech jab should only be delayed for up to six weeks.
Early signs ‘very promising’
Professor Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (JCVI), said he is “absolutely convinced” that the decision to delay the second dose will turn out to have been the right move.
Prof Harnden, who is also professor of primary care at the University of Oxford, said that delaying the second dose means that a greater number of people will receive a first dose, meaning more lives could be saved.
Speaking on a Royal Society of Medicine webinar, he said: “By our calculations, assuming 80 to 90 per cent of vaccine effectiveness in the over 80s, we calculated that we could save between 3,000 and 4,000 extra lives for every million first doses that we gave.
“And so given the dire situation around the country at the moment with, you know, having exceeded the 100,000 grim deaths statistic, (we) really felt that we could save many, many more thousands of elderly people’s lives by this strategy.
“And interesting enough, I’ve just come off JCVI and we’re looking at these real time vaccine effectiveness figures, it’s really early stages yet, but it does look like our first dose strategy is proving to be a good one.
“And the early signs are very promising from the data that we’ve made the right decision on this.”
Prof Harnden explained that the JCVI has acted “nimbly, quickly and promptly” to make a “bold decision” based on the data they have seen, and added that he predicts the WHO will come round to the UK’s delayed second dose strategy.
He said: “I think that won’t be too long before that happens. And so the more that we see that data reassuring us that we’re making the right decision the more likely it is that WHO will come into line.
“I think it will turn out to be the right decision. I’m absolutely convinced it will turn out to be the right decision. But we are reviewing this every single week.”
‘No cause for concern’
Eleanor Riley, professor of immunology and infectious disease at the University of Edinburgh, said she wanted to warmly congratulate the JCVI on what she described as a “very bold” decision and spoke of the importance of people getting the second dose.
She said: “As an immunologist, the data suggests that the second dose is really important. The boost you get to your immune system after the second dose is huge.
“The first dose will get them through 12 weeks, I’m fairly confident about that, but in order to get that long-lasting protection people do have to come back.
“So I would plead with the people rolling out the vaccine not to delay it past 12 weeks.”
Prof Riley said there is data from other vaccines where a delayed second dose was “hugely beneficial”, adding: “I think there’s theoretical reasons to think that a delayed dose is better.
“I think there is also practical evidence that a delayed dose is no worse, and may be better.
“And I think the data that we’ve seen so far from the pre-clinical studies looking in detail at the T-cell and antibody responses suggests that there’s no dropping off a cliff of the response in the first few weeks after vaccination that would give us cause for concern.”