Boris Johnson has insisted he is not concerned after German officials said the AstraZeneca vaccine should only be recommended for under 65s.
The Prime Minister joined Public Health England (PHE) in defending the use of the jab after a draft recommendation from Germany’s vaccination advisory committee (STIKO) on Thursday said there was insufficient data to recommend it for those aged 65 and over.
The EU’s European Medicines Agency (EMA) is expected to make a decision regarding the jab’s roll-out on the rest of the continent on 29 January.
Johnson said the evidence shows it “provides a good immune response across all age groups”.
Dr Mary Ramsay, head of immunisations at PHE, acknowledged there had been “too few cases” of coronavirus in older people in Phase 3 clinical trials to determine the level of efficacy in this age group, but said other data on immune response had been “reassuring”.
Mr Johnson, during a visit to Scotland, said he did not agree with the German ruling, as he backed the advice from the UK’s Medicines and Healthcare products Regulatory Agency (MHRA).
He said: “The MHRA, our own authorities, have made it very clear that they think the Oxford/AstraZeneca vaccine is very good and efficacious, gives a high degree of protection after just one dose and even more after two doses.
“And the evidence they’ve supplied is they think it’s effective across all age groups and provides a good immune response across all age groups.”
It comes after German coalition sources reportedly told the newspaper Handelsblatt the jab is expected to be just 8% effective in this older age group.
The publication Bild later quoted anonymous sources saying the vaccine was not expected to be given the green light by the EMA, blaming a hotly disputed efficacy rate of “less than 10%” among the elderly.
Germany’s ministry of health has since dismissed the efficacy claims, while AstraZeneca and the University of Oxford called them “completely incorrect” with “no basis”.
The latest news comes amid tensions between the UK and EU over the rollout, with Brussels threatening to block the export of millions of doses of vaccine to the UK.
Michael Gove has reassured there “will be no interruption” to UK coronavirus vaccine supplies after the EU urged AstraZeneca to supply it with doses from UK plants.
STIKO said its ruling on the AstraZeneca jab did not apply to the Pfizer-BioNTech and Moderna jabs.
‘Every country is different’
In response to STIKO’s recommendation, the chief executive of the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) Dr June Raine said: “Current evidence does not suggest any lack of protection against Covid-19 in people aged 65 or over.
“The data we have shows that the vaccine produces a strong immune response in the over 65s.
Professor Stephen Evans from the London School of Hygiene & Tropical Medicine said it was “reasonable” for Germany officials to prioritise younger people with one jab and older people with another.
“Every country is in a different situation. Advice on the use of a vaccine will depend on its availability and the availability of other vaccines,” he said.
“For the Oxford-AstraZeneca vaccine, in Germany and the rest of the EU there is a shortage, as is well-known. It is in a context where supplies of the Pfizer-BioNTech vaccine, for which data in older people shows similar efficacy as in younger people, are relatively plentiful.”
With millions of Britons already receiving the AZ vaccine’s first dose, another expert has stressed it is highly likely they will have some immunity.
“I would say to anyone over 65 who has had the AZ [AstraZeneca] jab the same I would tell anyone who has had any COVID jab – ‘we already know no vaccine available is 100% protective against getting sick, and at the moment you should still behave as if you, and anyone around you, could be infected with COVID-19’,” said Professor Simon Clarke from the University of Reading.
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“We know the AZ jab provides some protection, but because the trials recruited only a few hundred over 65s, the data are not clear enough to say for sure exactly how effective it is.”
Dr Ramsay added the AstraZeneca-Oxford vaccine has been shown to be safe and protect against COVID-19, much like the Pfizer-BioNTech jab.
“There were too few cases in older people in the AstraZeneca trials to observe precise levels of protection in this group, but data on immune responses were very reassuring,” she said.
“The risk of severe disease and death increase exponentially with age.
“The priority is to vaccinate as many vulnerable people as possible with either vaccine, to protect more people and save more lives.”
An AstraZeneca spokesperson said: “The latest analyses of clinical trial data for the AstraZeneca/Oxford COVID-19 [the disease caused by the coronavirus] vaccine support efficacy in the over 65 years age group.”
Low efficacy clams ‘make no sense’
Concerns over the poor efficacy of the AZ jab in the over-65s were first raised by the reports it could be as low as 8% in German media, though the country’s health ministry has since rubbished them.
“Around 8% of the volunteers in AstraZeneca’s efficacy studies were around 56 and 69 years old and 3-4% are above 70 years old,” it said.
“However, this does not mean that it is effective only in 8% of older people.”
The clinical trial that led to the AstraZeneca-Oxford vaccine being approved in the UK reported an overall efficacy result of 70%.
Surprisingly, the two-dose regimen was reported to have up to 90% efficacy when the first vaccine was given at a half dose, followed by a full dose 28 days later.
When both jabs were full dose, efficacy was reported at 62%.
The participants who received the low-dose then full-dose were not initially over 55 due to the first vaccine being administered early in the trial, before older adults had been recruited.
The double full-dose regimen was given to participants of a range of ages.
Writing in The Lancet, the study’s authors said: “As older age groups were recruited later than younger age groups, there has been less time for cases to accrue and as a result, efficacy data in these cohorts are currently limited by the small number of cases, but additional data will be available in future analyses.”
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AstraZeneca’s CEO has previously said “the issue with the elderly data is not so much whether it works or not. It’s that we have today a limited amount of data in the older population”.
The scientists behind the jab reportedly “didn’t want to vaccinate older people until they had accumulated a lot of safety data in the 18 to 55 group”.
“Other companies took this risk, went ahead and vaccinated older people faster or earlier,” said the CEO. “We have strong data showing very strong antibody production against the virus in the elderly, similar to what we see in younger people.
“It’s possible some countries, out of caution, will use our vaccine for the younger group.”
Experts have generally dismissed reports of the low efficacy claims as having no basis.
“[I have] no idea where the 8% figure comes from,” Professor Adam Finn from the University of Bristol previously said.
Dr Hassan Vally from the La Trobe University in Melbourne called the claim “completely false”, adding “it is not immediately obvious where this number has come from”.
Professor James Naismith from the University of Oxford said that when it comes to questionable efficacy results: “Experimental evidence and reasoned debate, not over heated rhetoric, will resolve this issue”.
“There is no need to impugn the quality or character of the German scientists [at STIKO] here; the UK’s MHRA advised by scientists of equal calibre have come to a different conclusion,” he said.
“Scientists often disagree about how much evidence is needed for any new advance and there is always more data to be secured.”
While data may be lacking, Dr Vally argued an efficacy result as low as 8% does not make theoretical sense.
“Given the relatively high efficacy estimates overall for this vaccine, an efficacy of less than 10% for those over 65 years does not make sense biologically,” he said.
“It would mean that there is something dramatically different in the way the immune system responds to the vaccine to make the vaccine essentially almost completely ineffective in this older age group.
“One could completely understand if the studies showed a reduced efficacy in this older group, as the immune system clearly ages like the rest of the body.
“However, a result as substantial as this does not really fit in with what one might expect to see.”
Like with the Pfizer-BioNTech and Moderna data, blood samples taken from older people who had the Oxford-AstraZeneca vaccine “do not suggest there will be notably lower efficacy”, added Professor Evans.
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