An expert has warned that rolling out a coronavirus vaccine too early would mean not knowing whether it gives long-term immunity.

Professor Robin Shattock, head of mucosal infection and immunity at Imperial College London, said it is not currently known how long Covid-19 immunity lasts.

But he told a Royal Society of Medicine (RSM) webinar that it is known that coronavirus infections give relatively short-lived immunity.

The ideal vaccine would be one that prevented infection and prevented transmission that would be the kind of the Holy Grail

He added: “We do know that coronavirus infections themselves give relatively short-lived immunity.

“So we hope that a vaccine will do better than that. I think one of the dangers that we may see is if vaccines are rolled out early after a few months of data, we’ll know that they’re protective for a few months, we won’t know whether they give long-term immunity.

“So, there is a danger of moving too fast, and we need to keep monitoring to look at duration.

“And I think we need to have a fallback that if we do need annual boosting that we have the capacity to do that.

“I think that’s a sensible risk reduction strategy.”

Prof Shattock is leading a team at Imperial College London in developing a vaccine that is due to start human trials next week.

The RNA vaccine delivers genetic instructions to muscle cells to make the “spike” protein on the surface of coronavirus.

The presence of this protein provokes an immune response, offering protection against Covid-19.

Prof Shattock said: “The ideal vaccine would be one that prevented infection and prevented transmission that would be the kind of the Holy Grail.

“But in the absence of that a vaccine that just reduces illness, so people don’t have time off work, or even a vaccine that only reduces severity of disease so we don’t see fatalities would be really useful at this stage, and I suspect we may see that.

“Some vaccines may be less than ideal but may be useful initially, and may be replaced by more potent vaccines as we get increasing clinical data and efficacy data.

“But the most important aspect at this time is for us to see the data for people to be transparent to show results rather than press releases, so that we can see comparison of these different approaches.”

Asked when a vaccine from Imperial may be available, he said potentially in the first two quarters of next year if everything goes well.

But Prof Shattock added that there is no guarantee any individual vaccine will work, and that it is important to deal with facts and data rather than over-promising and under-delivering.