Coronavirus: Is the Oxford vaccine less good than the others? Not necessarily

It’s cheaper, and easier to preserve, so why is the Oxford vaccine seen by some as an also-ran in virus race?

An undated handout picture released by the University of Oxford on November 23, 2020 shows a vial of the University's COVID-19 candidate vaccine. Picture: AFP/University of Oxford/John Cairns

When it comes to scientific glory, timing is everything. Three weeks ago the announcement from Oxford would have been the biggest story in the world: a vaccine developed in record time, with higher efficacy than expected.

Now, it is simply the third such vaccine and — on headline results at least — it is less good than the competition.

What we know from the data is that Oxford’s vaccine appears to prevent 70 per cent of symptomatic COVID-19 infections.

This is a lot more than the flu vaccine, which ranges from 30-60 per cent, but a lot less than the 95 per cent for the two vaccines already announced.

There are hints of an intriguing caveat though. It may be even better if you use half the quantity for the first dose. Then, the scientists claim, it is perhaps 90 per cent effective.

There are, the Oxford team said on Monday, theoretical reasons why this might be correct. It is possible, for instance, that the half dose may better mimic what happens in a real infection and so fool the immune system more convincingly.

There are also, however, statistical reasons to be sceptical.

Monday’s findings are based on an analysis of 131 infections. The analysis that produced the 90 per cent figure is based on a subset — probably about a third — of those 131 infections. Once you start slicing the data, you are making decisions on the basis of few cases.

The good news is we will not have to wait long for a clearer idea. The data analysed so far comes from cases up to November 4. There have been plenty more since. A more confident answer to the vaccine’s true efficacy already exists – the researchers just have to collate it.

In science, there is rarely a reward for second or third place. But this is not science, this is public health, and we need every vaccine we can get.

This is why Oxford’s announcement is just as important now as it would have been three weeks ago. The light at the end of the tunnel is getting a lot brighter.

The Times