Speed of essence for vaccines but so is clarity around data

Cantillon: Many questions remain on how Covid-19 vaccines work

Three Covid vaccines are now before US and European regulators seeking approval for use in the general population. Some countries are ready to start vaccinating within days, assuming the vaccines get the green light. Others, less so.

In Ireland, the national vaccination task force only held its second meeting on Monday as it looks to put in place a strategy and a structure for the rollout of what will likely be a number of different vaccines.

But much still remains to be clarified about the vaccines themselves. They have been developed in a fraction of the usual timescale – in large part because the pandemic has concentrated resources in a way that would never be possible in normal circumstances.

Chief among these is clarity on what the vaccine candidates are doing – protecting against infection or just against disease?


Efficacy rates

The data disclosed to date, showing efficacy rates of 90 per cent or higher, relate to how many people who receive the vaccine actually then get sick from Covid-19. That’s clearly very good news but it doesn’t shed any light on whether people can get infected by the coronavirus even if they do not actually get sick.

This is important because, clearly, if people are infected but asymptomatic, they could infect others. A vaccine that prevented infection in the first place would be better still, and one or more of those in development may do so but we have not seen that data yet.

There also remains some confusion over how effective different age cohorts will find the vaccines.

Placebo group

One of the three, Moderna on Monday said that 33 older people (those over the age of 65) had contracted Covid during its Phase III trial. What it didn’t say was how many of these had received the vaccine and how many were in the control group receiving a placebo.

That’s the danger of what scientists dismissively refer to as “vaccine development by press release”.

Vaccination is important, never more so that with this pandemic. The last thing the doctors, or the vaccine developers want, is anything that gives people pause for thought about taking their shot. Speed is clearly of the essence but the sooner the full data is available, the better.