Covid booster shots not needed this winter as two jabs are so effective, says Oxford expert
THE Oxford vaccine is so effective that autumn booster shots may not be needed, its makers have said.
Protection against the virus remains for at least a year after just one dose - and stays at more than 90 per cent “for quite some months” with two jabs, new tests have shown.
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Oxford announced today its vaccine CAN be used as a third-dose booster following trials, producing “a substantial increase in antibodies”.
But Prof Sir Andrew Pollard, director of the Oxford Vaccine Group, said: “There’s no indication today that we need boosters.
"We have data showing very good levels of protection for quite some months after the second dose - over 90 per cent.
“We need to keep looking at the data as the months go by. We would expect to see immunity start to wane over time, but our immune systems are very clever and will remember that we’ve been vaccinated.”
Prof Pollard said "boosters are much more about if protection gets lost over time" and it wasn't clear that this was the case after two jabs.
It comes as a separate study has shown for the first time that mixing doses of the Oxford/AstraZeneca and Pfizer/BioNTech vaccines is both safe and effective.
The results from the Com-COV study, run by the University of Oxford, is unlikely to change the current course of the UK’s vaccine programme.
But it will be useful for rollouts in nations where vaccine supply is more limited, and giving people whatever second dose is available is quicker than waiting for a matching one.
Third dose planned
Deputy chief medical officer, Professor Jonathan Van-Tam, said today that research suggests mixing doses would provide "greater flexibility for a booster programme".
The new Health Secretary Sajid Javid also told the Commons this afternoon: "A mixed schedule of jabs such as the AstraZeneca first and then Pfizer second could give our booster vaccination program more flexibility and possibly some better immune responses."
It's another sign that ministers are planning a booster campiagn as early as September in the most vulnerable.
Matt Hancock, who has this weekend resigned as Health Secretary, said last week people may be given a flu jab and a Covid booster shot at the same time this winter.
But Prof Pollard said there was no evidence boosters were needed, and said it would be “unacceptable” to give fully-protected Brits unnecessary booster jabs when parts of the world have yet to receive any vaccine.
He said: “With high levels of protection in the UK population and no evidence of that being lost, to give third doses now in the UK while other countries have zero doses is not acceptable.
“We really have to make sure that other countries are protected, for our own good as much as theirs.”
In the preprint study, which has yet to be peer-reviewed, some 90 people received a third dose of the vaccine, which was well-tolerated in terms of side-effects.
The third shot - more than six months after the second - led to a substantial rise in antibodies.
Teresa Lambe, associate professor at the Jenner Institute at Oxford, said "we were able to push them up to a level that we saw at the peak of the response after the second dose".
It also increased the body's T-cell ability to fight coronavirus, including against new variants.
Prof Lambe said: "We were able to demonstration increased neutralising antibodies with a third dose against Alpha, Beta and Delta."
The study also found that the longer the delay between the first and second dose of the vaccine, the stronger the protection against Covid.
A longer delay of up to 45 weeks (ten months) between two AstraZeneca vaccine leads to enhanced immune response.
The experts said this is reassuring for countries with limited vaccine supply that can't give people two doses quickly.
Meanwhile, the Com-COV study has revealed what combination of Oxford and Pfizer jabs are best for Covid protection.
The study, published today on the Lancet pre-print server, found that using Pfizer followed by Oxford or vice versa induced high antibodies when doses were given four weeks apart.
Mix-and-match is safe
Oxford followed by Pfizer induced higher antibodies and T cell responses than Pfizer followed by Oxford.
But both schedules induced higher antibodies than the two-dose Oxford/AstraZeneca schedule.
The highest antibody response was seen after two doses of the Pfizer jab, and the highest T cell response from Oxford followed by Pfizer.
T cells play an important role in supporting and maintaining antibody production.
The study looked at a four-week interval, but the UK is using an eight to 12-week gap.
Prof Van-Tam said: “The results for the 12-week interval, which are yet to come, will have an instrumental role to play in decisions on the future of the UK’s vaccination programme."
“Our non-mixed (homologous) vaccination programme has already saved tens of thousands of lives across the UK but we now know mixing doses could provide us with even greater flexibility for a booster programme..."
He said although the UK’s rollout won’t change, “today’s data are a vital step forward, showing a mixed schedule gives people protective immunity”.
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It comes as trials of a new variant vaccine, also developed in Oxford, targeting the South African “Beta” mutation are due to start this week.
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The booster vaccine trial will involve around 2,250 participants from Britain, South Africa, Brazil and Poland.
The Beta variant has been worrying scientists because it appears to have the most ability to dodge immunity - more than Delta, first seen in India.