Professor Sir Ian Boyd, of the University of St Andrews, said that the UK could end up in a pattern of “control and release” due to potentially vaccine-resistant Covid variants.
It comes after early trials suggests the Oxford/AstraZeneca jab offers “minimal protection” against mild disease from the South Africa variant.
Officials fear the mutation – believed to be capable of evading vaccines – is already widespread in the UK and have ramped up doorstep surge testing.
The Government’s scientific advisers have assured that the vaccine – the main weapon in Britain’s fight against Covid – can still protect against severe illness and death.
But Prof Boyd, along with other prominent Sage members, say that relaxing the current restrictions too early could allow more variants to emerge.
They suggest that Brits should “take the pain” of longer restrictions to reduce the risk of mutations prompting repeated shutdowns.
Prof Boyd, an infectious disease expert, told The Times that early release of lockdown measures “tends to be a false economy because it simply fuels a new wave of disease”.
He added: “It stands to reason that the more people there are in the population with infections - the prevalence – the more virus that is replicating and the more chance there is of even highly improbably mutations happening.”
He also said that it could take a few months to adapt vaccines to tackle emerging variants.
“It will take some time, simply because although the new variants can be adjusted in the vaccines they then have to come through the regulators, and then have to be manufactured at scale in order to be available,” he said.
“So it’s not a matter of a month or two, it’s probably more than that.
“But we currently have vaccines that are effective against the strains that are predominating in the UK and that should be clear in everybody’s minds, that we’re not in a position where vaccines have suddenly stopped working entirely.”