THE GREAT OXFORD VACCINE DILEMMA
REGULATORS are f acing a ‘dilemma’ over t he Oxford University vaccine, it has been warned, after r esults were formally published.
Last month it was revealed that the jab – of which the UK has ordered 100million doses – was 70.4 per cent effective.
But it was 90 per cent effective when people received a half-dose for their first jab and a second standard-dose booster jab after that. When they received two standard doses, the efficacy fell to only 62.1 per cent.
Now the full data on vaccine trials in the UK, Brazil and South Africa has been published in the Lancet medical journal, and comments from researchers in the article highlight the problems potentially facing regulators in deciding whether to approve the vaccine with a low-dose initial injection.
The scientists say the 90 per cent effectiveness is ‘intriguingly high’ in people given a low- dose first jab, but that further data is needed to confirm the preliminary findings.
They also acknowledge that chance may have played a part in the findings, which were only seen in younger people aged 18 to 55.
Nonetheless, many experts say a vaccine which is over 50 per cent effective is more than good enough, and that the Oxford vaccine is better than the flu jab in most years.
The Oxford study, which swabbed volunteers every week, also provides some evidence the vaccine may prevent people falling ill without symptoms. That is an import ant i ndication i t could prevent the virus spreading and help herd immunity.
Professor Sarah Gilbert, leader of the Oxford University team which developed the vaccine, told a briefing yesterday: ‘This is probably the best day we’ve had in 2020. Not only are we seeing the first roll-out of NHS vaccinations against Covid-19, but we are able to present to you our data in a peer- reviewed publication.’
The results on how well the vaccine works, based on 11,636 trial volunteers, are welcome because the Oxford vaccine, unlike the Pfizer one currently being put into British people’s arms, can be kept at normal fridge temperatures.
That makes i t easier to deliver to people, as it does not require specialist freezers. But the data, currently being studied by the Medicines and Healthcare products Regulatory Agency (MHRA), is not straightforward.
Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading, said: ‘The report on the successful trial of the Oxford/AstraZeneca presents regulators with something of a dilemma.
‘Data are most compelling for the cohort who got half a dose of the vaccine in their first jab. Not only does this seem to confer greater protection against disease, it is in this group that there is a reduction in asymptomatic transmission of the virus – something which is essential if herd i mmunity is t o be obtained to get wider protection of the population.
‘Unfortunately, this cohort was relatively small, reducing the reliability of the findings – moreover it did not contain any older participants [age 55 or over] and it remains possible that i f the regulators allowed the vaccine to be used i n this manner, the most at- risk group may not be protected.’
Professor Andrew Pollard, chief i nvestigator of the Oxford vaccine trials, said: ‘It is entirely up to the regulators to look at the data and decide exactly what they think their label should say at the end, and so that’s in their hands.’
‘May not be protected’