A THIRD Oxford vaccine jab can be used as an effective booster jab against coronavirus variants

By | June 29, 2021

Third AstraZeneca jab after six months enhances protection against Covid variants, Oxford study suggests but scientists say boosters are not needed this winter because two doses are working so well

  • Scientists find booster jabs help fight Kent, South African and Indian variants
  • A third jab six months after second dose increases neutralising antibodies
  • Researchers say finding is ‘encouraging’ if No10 launches booster programme
  • But lead professor said no proof it would improve on current two-dose regimen
  • Researchers also found that one Covid jab offers protection for at least one year 

Professor Sir Andrew Pollard said there is 'no indication at the moment that we need boosters', despite his study showing that the third jab gave high protection against Covid

Professor Sir Andrew Pollard said there is ‘no indication at the moment that we need boosters’, despite his study showing that the third jab gave high protection against Covid

A third dose of the AstraZeneca vaccine may offer enhanced protection against Covid variants, a study has suggested.

Scientists at Oxford University found that a booster jab given six months after the second dose increased levels of antibodies that target the Indian, Kent and South African strains. 

The findings will give No10 confidence that the AstraZeneca vaccine can be used in a booster vaccine programme this autumn. 

However, the lead scientist behind the trials said the standard two-dose regimen was working so well that there was little need for a third shot yet. 

Studies have shown that two doses of AstraZeneca or Pfizer reduce hospitalisations by up to 96 per cent from the currently dominant Indian variant. Protection is even higher against the Kent one.

And the latest study found that antibody levels remain elevated for at least one year after a single dose of the AZ vaccine, with protection from two jabs likely to prevail even longer. 

Professor Sir Andrew Pollard claimed sending the extra doses to developing countries where the most vulnerable are yet to receive any jab would be a better use of the UK’s supplies. 

It comes after Oxford University began trialling a tweaked booster jab at the weekend, which is adapted for the South African variant, feared to be the next looming threat to the UK.

Last week, the former Health Secretary Matt Hancock promised the Government would set out plans for an autumn booster programme within the next few weeks.  

The green vertical lines show participants' antibody levels when they were given the first vaccine (V1), 28 days after that (V1+28 days), the second jab (V2), 28 days after that jab (V2+28 days), the third booster injection (V3), 14 days after that (V3+14) and 28 days after the booster (V3+28). The findings show that the antibody response increased after each jab and were at their highest, by a small margin, 28 days after the booster injection

The green vertical lines show participants’ antibody levels when they were given the first vaccine (V1), 28 days after that (V1+28 days), the second jab (V2), 28 days after that jab (V2+28 days), the third booster injection (V3), 14 days after that (V3+14) and 28 days after the booster (V3+28). The findings show that the antibody response increased after each jab and were at their highest, by a small margin, 28 days after the booster injection

The scientists also measured antibody levels when there was a different length of time between the first and second jab. They found that antibodies were at their highest 28 days after the second dose when there was  a 44 to 45 week delay between the injections. The lowest levels were found when there was just an eight to 12 week delay, while a 15 to 25 week lag was in the middle

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The scientists also measured antibody levels when there was a different length of time between the first and second jab. They found that antibodies were at their highest 28 days after the second dose when there was  a 44 to 45 week delay between the injections. The lowest levels were found when there was just an eight to 12 week delay, while a 15 to 25 week lag was in the middle

The Oxford University researchers found that antibody levels are elevated for at least one year after a singe dose of the Oxford AstraZeneva vaccine. The red line shows the level of antibodies recorded in 261 people for one year from the day they were vaccinated. Antibodies dropped over the course of the year, but remained higher than before the jab was given

The Oxford University researchers found that antibody levels are elevated for at least one year after a singe dose of the Oxford AstraZeneva vaccine. The red line shows the level of antibodies recorded in 261 people for one year from the day they were vaccinated. Antibodies dropped over the course of the year, but remained higher than before the jab was given

Figures from Our World in Data show that the UK has vaccinated 65.28 per cent of the whole population, but separate government data shows that 84.4 per cent of over-18s have had at least one Covid injection. Malta, Iceland, Canada and Chile have administered the highest proportion of first doses, according to the statistics

Figures from Our World in Data show that the UK has vaccinated 65.28 per cent of the whole population, but separate government data shows that 84.4 per cent of over-18s have had at least one Covid injection. Malta, Iceland, Canada and Chile have administered the highest proportion of first doses, according to the statistics

The new results come from laboratory tests that gave 90 volunteers – who had the average age of 40 – a third dose of the Oxford vaccine. Their blood was then taken to measure levels of antibodies. 

Researchers found neutralising antibodies increased significantly after the third dose, compared to the second dose for the variants. 

But Professor Pollard cautioned that it was not clear how antibody levels would translate into protection in the real world. 

Teresa Lambe, associate professor at the Jenner Institute at Oxford, and lead senior author of the study, said: ‘This is very encouraging news, if we find that a third dose is needed.’   

New jab that targets South African variant trialled by Oxford University

The University of Oxford yesterday began administering doses a new Covid jab – called AZD2816 – that targets the South African ‘Beta’ variant. 

The university has partnered with AstraZeneca to give 2,250 participants in the UK, South Africa, Brazil and Poland the jab.

The scientists are trialling the jab in people who have had no, one and both jabs. 

For those who have not been vaccinated, they will get two doses four or twelve weeks apart.

People who have had one Oxford AstraZeneca jab already can get the new vaccine as their second jab after four weeks.

Double-jabbed participants must have already had their second dose of the Oxford vaccine, or another mRNA jab, three month ago.

The Beta variant is only responsible for 0.1 per cent of cases in England, according to data from the Sanger Institute, but it is feared to be the next looming threat because it is vaccine resistant.

Oxford University Professor Sir Andrew Pollard, who is chief investigator of the study, said: ‘Testing booster doses of existing vaccines and new variant vaccines is important to ensure we are best prepared to stay ahead of the pandemic coronavirus, should their use be needed.’

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Dr Maheshi Ramasamy, principal investigator at the Oxford Vaccine Group, said: ‘The UK vaccine roll out programme has been incredibly successful at preventing hospitalisations and deaths, but we don’t know how long protection lasts. 

‘This study will provide vital evidence on whether further doses including ‘tweaks’ against new virus variants may be needed in the future.’ 

The researchers plan to submit trail stat to regulators later this year

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Additionally, the researchers also saw higher levels T-cells, a type of white blood cell that plays a role in defending from the infection, were also boosted.

Professor Pollard said the booster shot could be used if the South African ‘Beta’ variant starts to take off in the UK.

That strain is considered the most resistant to vaccines but is circulating in low numbers in the UK.

Some scientists believe it could rise to the top when the entire nation is vaccinated and other variants find it difficult to spread. 

‘The reason why these new trials are so important is because we know that the Beta variant is a variant which has been quite good at escaping vaccine immunity,’ Professor Pollard said.

‘So it is a good idea to have new vaccines available which could cope with that, if it became more of a problem.’ 

But he said said there was little need to give a third dose to people now because the double dose statreg already works so well against the Indian ‘Delta’ and Kent ‘Alpha’ variants.    

The policy question of whether third jabs should be rolled out this year ‘cannot be  answered from a scientific perspective at this point’, Professor Pollard said.

‘At this level of high protection in the UK to give third doses now when others do not have first doses is not acceptable. We need to make sure other countries are protected.’

He added that two Covid vaccines already offer ‘very high levels of protection’ against the virus, as well as variants of concern, even though they were designed to protect against the original mutation. 

Giving people in the UK a third injection when at-risk people in other countries have not had any ‘is not acceptable’, he said.

Professor Teresa Lambe, who was also involved in the study, said: ‘It is not known if booster jabs will be needed due to waning immunity or to augment immunity against variants of concern.’ 

Some countries have not been able to source enough vaccines to give people their second jab within the eight to 12 weeks recommend by the World Health Organization, and this has led to concerns that people with just one jab will have compromised immunity, they said.

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Researchers found that antibody levels 28 days after the second dose got higher the longer that was left between doses.

Professor Pollard said it is ‘fairly typical’ for vaccines to offer a better response if a longer window is left between jabs.

But is it a ‘trade-off’ between giving two doses to get better protection in the population more quickly, or waiting longer between jabs to boost the effectiveness of the vaccines.

They also monitored 261 peoples’ immune response after they received just one dose of the vaccine.

The Oxford scientists previously found that one jab offered protection for at least three months. But they have now found that antibody levels are elevated for at least one year after a singe dose. 

Antibodies dropped over the course of the year after a single jab, but remained higher than before the jab was given, the researchers found. 

Government data shows that 44.3million people in the UK have received their first dose of the vaccine, while 32.4million have had two jabs

The scientists said this was important for countries where second doses are delayed due to a shortage of supply.

It comes as data from Saturday shows that 44.3million people in the UK have received their first dose of the vaccine, while 32.4million have had two jabs. 

All over-18s can now get a Covid vaccine, with hundreds of vaccination sites operating on a walk-in basis over the weekend.

Oxford University yesterday launched a trial that will give around 2,250 participants in the UK, South Africa, Brazil and Poland a new Covid vaccine that targets the South African ‘Beta’ variant.

The Beta variant is only responsible for 0.1 per cent of cases in England, according to data from the Sanger Institute, but it is feared to be the next looming threat because it is vaccine resistant.

A study by scientists at the Tel Aviv University, which was published in April, found that the South African variant was eight times more prevalent in people who had both Covid jabs.

Meanwhile, Professor Pollard told BBC Radio 4’s Today programme this morning that the UK is in a ‘very good position’ for restrictions being lifted.

He said: ‘We’re looking at the data that’s coming from Public Health England about the effectiveness of the vaccines and we’re seeing more than 90% protection.

‘If that persists as more and more data emerge, and we will get much greater certainty of those figures in the weeks ahead, then we reach a point where, with most people vaccinated with at least one dose and those at highest risk having two doses, it does put us in a very good position.

‘But in the end it’s going to be a political decision about the timing of when those should end.’


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