Health experts “haven’t seen any hint” at the moment of a Covid variant that can fully evade the effectiveness of vaccines, a leading scientist has said.

Sharon Peacock, head of the Covid-19 Genomics UK Consortium (COG-UK) and professor of public health and microbiology at the University of Cambridge, said it could be the case that coronavirus mutates to become less infectious, though she warned it could take years for it to become like the common cold.

Asked whether a variant will emerge somewhere across the globe that is resistant to current vaccines, Prof Peacock told Times Radio: “That’s what we’d call it, a variant of major concern. We haven’t seen anything like that to date, and the question you’re asking is the million dollar question in many ways, everybody wants to know what’s the likelihood and when is it likely to occur, if at all.

“What we don’t know is if it is likely to occur. We know that as mutations accumulate in the virus, it can actually make it more fit in terms of avoiding our immune system, but the more mutations it accumulates, it could actually lead to a virus that is less infectious, for example.

“So there’s a trade-off for the virus in terms of how many mutations it can tolerate.

“Now, some people have predicted that a virus could emerge that is pretty resistant to vaccines, but we haven’t seen any hint of that at the moment.

“And the idea that this could arise is based on models from previous viruses, not this current one, so at the moment, I remain optimistic that we’re in a good place – that the viruses that are circulating are susceptible to vaccinations.

“And the key thing is to get on and vaccinate the world so that we can clamp down [on] disease. If we can reduce disease rates, then we reduce the risk of variants arising in the first place.”

Prof Peacock said work was ongoing to look at the variant first identified in India, including whether it could spread in the UK compared to the Kent variant.

The Indian government has said the coronavirus variant first discovered there in March may be linked to its deadly second wave.

Samples for the B.1.617 variant have been found in several states with high case numbers, it said.

The National Centre for Disease Control said, however, that it had still been unable to fully establish a correlation.

It could take one or two generations before we see a virus that causes less severe disease

Asked about the variant, which has been found in a small number of cases in the UK and is currently regarded as a variant under investigation, Prof Peacock said: “My eyes are constantly now looking at the pattern of spread within the United Kingdom to see whether this variant is able to spread in our population under current restrictions.

“There’s no evidence at the moment that the variant described in India, which we call B.1.617, is resistant to the vaccine, far more work needs to be done.

“Very early work suggests that it’s not as resistant as, say, the variant first described in South Africa.

“But what we don’t know about this particular variant from India is how transmissible it is, so that’s the other key question.

“The big question for me, is whether the Indian variant is also particularly transmissible.

“Now we can see that through experimental work, but the key is to watch it in the population, to see whether it’s associated with outbreaks and spread in the community.

“I know that Public Health England are really looking very carefully at that because that’s a sign that under the circumstances we’re under in terms of our current restrictions, whether that is spreading is a key signal – a public health signal of transmissibility.

“We’d obviously have to prove that scientifically, but that’s a really key thing to watch out for.”

Prof Peacock suggested richer nations should be doing all they can to help vaccinate people in poorer countries.

She said: “We in wealthy countries should be thinking about people who are less fortunate than ourselves,” and added: “We should be vaccinating the world on a moral standpoint, but also vaccinating the world to try and reduce the rate of infection, so that we protect people from an untimely death, but also reduce the risk of variants emerging in the first place, because ultimately in the long-term, that is one of the major threats to us controlling this pandemic.”

Asked whether Covid will become like annual seasonal flu, she said: “The idea that the virus will become like a common cold and nobody will notice it by next spring is far too optimistic.

“And so it could take one or two generations before we see a virus that starts to, what we say attenuate, which means it causes less severe disease, and so, I think, what we have to do is tackle the problem that’s in front of us at the moment and not put too much store in the fact that the virus is going to evolve into something that’s really rather harmless.

“That’s been seen for other viruses, but that’s over a process of decades and hundreds of years, and we’re talking about being in the very early stages, [we] still have a pandemic, so we can’t guarantee that that’s the trajectory of the virus right now.”

The comments come as Canada became the first country to authorise a vaccine for children aged 12 to 15.

It authorised Pfizer after studies showed the jab worked well in that age group.