Last week, I posted twice about the Oxford vaccine and its efficacy rate, and it turns out I was not alone in not fully understanding the trial results. Indeed, concerns around the efficacy of the Oxford University/AstraZeneca vaccine in older people could lead to different age groups being given different vaccines.
Their results announced last week reported that the vaccine had an overall 70% efficacy rate. Most trial participants were given two full doses, spaced a month apart with an efficacy rate of 62%, but 3,000 participants were mistakenly given half a dose for their first jab, with an efficacy rate of 90%. However, it has emerged that this group did not include any participants over the age of 55, meaning that it was unclear whether the 90% efficacy holds for older adults, with their much higher risk from Covid-19.
Speaking on BBC Radio 4’s Today programme, Prof David Salisbury, a former director of immunisation at the Department of Health said the further trials were important. “If this vaccine came through at truly 90% and it is a cheaper vaccine and it requires much less rigorous cold chain than the RNA vaccines [from Moderna and Pfizer/BioNTech], then that would be a great result,” he said. “But if it comes through at 62% and the other vaccines that are coming through so far are coming through at 90% then I think you have to think very carefully, what do we do with 100m doses of a product that isn’t protecting as well as the alternatives.”
Prof Helen Fletcher, a professor of immunology at the London School of Hygiene & Tropical Medicine said “With multiple vaccines available, I think it’s right for policymakers to think about which vaccines might work best in which populations. This is not unusual: we give three different types of flu vaccine in the UK to children, young adults and the elderly, as we know that different vaccine platforms work better in different age groups.”
Dr Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London, said: “I personally view this [Oxford/AstraZeneca] vaccine (and the others) as being like the influenza vaccination – ie they do not protect from infection but can reduce the severity of disease and, importantly, the risk of severe complications and death. “It is relevant here to note that influenza vaccination is 50-60% effective in most seasons but nonetheless reduces severity of disease and need for hospitalisation in the vaccinated older age population.”
So there we have it -a range of scientific views on vaccine policy. There is evidence that all three of these vaccines work to prevent disease, but it is not clear which of them will work best in the elderly or whether there will be any difference. Time will tell. Click full article