An Oxford-AstraZeneca vaccine can reduce coronavirus transmission by up to two-thirds, a study has suggested, and this is the first time a jab has had such an effect.
The Oxford University study published Tuesday, awaiting peer review, found that those vaccinated with a single dose of the vaccine were 67 percent less likely to test positive with a PCR test. .
The article suggests that the vaccine, developed by the University of Oxford in collaboration with the British-Swedish pharmaceutical giant AstraZeneca, could have a “significant effect on the transmission of the virus” and also prevent serious diseases.
Health Secretary Matt Hancock said the study, which also suggests the Oxford-AstraZeneca shot is very protective after a single dose, shows that “vaccines are the way out of this pandemic”.
“This news about the Oxford vaccine is absolutely excellent,” Hancock tweeted. “This vaccine works and works well.”
This news about the Oxford vaccine is absolutely excellent.
📉 2/3 reduction in transmission
💉 Stronger protection at twelve weeks between doses
Hospital No hospitalizationsThis vaccine works and works well 🇬🇧
https://t.co/B1WPLf6dJB– Matt Hancock (@MattHancock) 2 February 2021
Oxford academics approve 12-week dose interval
The study also showed that the vaccine was 76 percent effective against symptomatic infection for three months after a single dose, a level that increased as the second shot was delayed.
The results of trials in Britain, Brazil and South Africa showed that immune responses increased with a longer interval between the two doses, among participants aged 18 to 55 years.
“The effectiveness of vaccine after a single standard dose of vaccine from day 22 to day 90 after vaccination was 76 percent, and a modeled analysis indicated that protection did not decrease during this first three-month period,” said academics from Oxford said.
Their article added that the effectiveness of the vaccine was 82.4 percent with 12 or more weeks until the second dose, compared to 54.9 percent for those where the booster was given less than six weeks after the first dose.
The findings support the UK’s decision to extend the interval between the initial and increased dose of shots to 12 weeks, Oxford academics said.
The UK has decided to vaccinate as many people as possible as quickly as possible by extending the time between initial and booster surveys.
Andrew Pollard, chief investigator of the Oxford Vaccine Trial, said the data showed that the twelve-week interval “is the optimal approach to perform, ensuring that people are protected from 22 days to a single dose”.
The head of research at AstraZeneca said eight to twelve weeks between doses appeared to be the ‘sweet spot’ for efficacy, in contrast to Pfizer, which warned that the vaccine developed with German BioNTech had not been tested at such an interval. not.
Questions about the elderly
The study did not address growing questions about a lack of data on efficacy among the elderly, a group that has given the UK government the highest priority in its implementation.
The longest dose between 56 and older was between six and eight weeks, so there was no data on the efficacy of a 12-week dose gap in the group.
According to the study, none of the 12,408 people vaccinated with a single dose of the vaccine were hospitalized from 22 days after vaccination with COVID-19.
The European medicine regulator recommended the Oxford-AstraZeneca vaccine for adults of all ages, but also noted that there is not enough data to determine how well it will work in people over 55.
On Tuesday, Poland and Sweden will join countries that have decided to use AstraZeneca on the elderly.
The UK has expressed confidence that the vaccine works in all age groups and that it is ahead of other EU countries at the pace of its introduction, as it has been approved earlier.
Oxford University Pollard said on Wednesday that the team’s researchers also believe the vaccine will continue to provide protection against new variants of COVID-19, although they are still awaiting information.
Even if the virus adapts, “it does not mean that we will not still have protection against serious diseases,” he said.
“If we do have to update the vaccines, then it’s actually a relatively simple process that only takes a matter of months, rather than the huge efforts that everyone went through last year to run the very large-scale trials,” Pollard said. said. the BBC.