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There have been reports from Germany that the Oxford-AstraZeneca COVID-19 vaccine is not very effective for people over 65.
Prof Stephen Evans, Professor of Pharmacoepidemiology, London School of Hygiene & Tropical Medicine, said:
“There needs to be much more detail of any study of vaccine effectiveness before offering comment.
“The randomised data on immunogenicity does not suggest that there will be notably lower efficacy at older ages for the Oxford/Astra Zeneca vaccine.
“If however, these reports are based on the preliminary randomised trial data from The Lancet paper, it was stated there “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.”
“For example, it could be that a lower confidence interval was calculated on very preliminary data based on very few cases with a very wide interval, then a very low value of efficacy would be found, which would be misleading. The authors of The Lancet paper say additional data will become available and it will be best to rely on those data.”
A University of Oxford spokesperson said:
“There is no basis for the claims of very low efficacy of the Oxford-AstraZeneca vaccine which have been circulating in the media. The results of the clinical trials have already been published transparently in 5 peer-reviewed scientific publications showing similar immune responses in younger and older adults and a good safety profile, and high efficacy in younger adults. Furthermore, the preliminary efficacy data in older adults supports the importance of this vaccine for use in this population.”
A spokesman for AstraZeneca, said:
“Reports that the AstraZeneca/Oxford vaccine efficacy is as low as 8% in adults over 65 years are completely incorrect. In the UK, the JCVI supported use in this population and MHRA included this group without dose adjustment in the authorisation for emergency supply. In November, we published data in The Lancet demonstrating that older adults showed strong immune responses to the vaccine, with 100% of older adults generating spike-specific antibodies after the second dose.’”
Prof Adam Finn, Professor of Paediatrics at the University of Bristol, said:
“I can confirm what is stated about the Lancet paper – I’m not an author on that manuscript but I’ve have read it
“Elderly people were recruited to the UK phase 3 relatively late and were relatively well shielded, so there were few cases of COVID that had occurred at the time of submission of data to MHRA for approval.”
“There may have been more by the time of EMA submission.”
“No idea where the 8% figure comes from”
Reporting:
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Declared interests
Prof Stephen Evans: “No conflicts of interest. I am funded (one day per week) by LSHTM. They get funding from various companies, including Astra Zeneca and GSK but I am not funded by them, I have no involvement in obtaining funding from them and I am not an investigator on any grants obtained from them. I am the statistician to the ‘meta-Data Safety and Monitoring Board’ for CEPI. I am paid for my attendance at those meetings and will be paid expenses for travel if that occurs. I am a participant in the Oxford/Astra Zeneca trial, and on 13th January 2021 learnt I had received the active vaccine”
None others received.
[DOI were not requested for Oxford and Astra Zeneca as they are implicit.]