Plans to ease lockdown restrictions in the UK could hang "in the balance" because of the Indian coronavirus variant, a leading scientific adviser has warned.
Professor Neil Ferguson, an Imperial College London epidemiologist and key member of SAGE, said the now dominant strain would trigger a "small third wave" — but the next two or three weeks would be "critical" in deciding whether it was safe to move forward with easing restrictions.
The next lockdown review in Wales is due to be discussed next week, with the announcement on Friday (June 4), and any changes taking place on Monday, June 7.
First Minister Mark Drakeford has already indicated that he will be considering a move to alert level one of the coronavirus restrictions.
But Prof Ferguson says that the next two to three weeks will be crucial in determining how much of a risk the Indian variant will pose and whether the next phase of unlocking should go ahead.
The latest figures show there have been more than 3,200 cases of the India variant of concern have been identified in England, with 57 cases in Wales as of Monday.
Wales’ chief medical officer Frank Atherton has said the number of cases of the variant in Wales was an underestimate and is expected to rise.
Prof Ferguson told BBC Radio 4's Today programme on Thursday that the threat of the Indian variant was still partially unknown.
He said: 'We're still working to assess exactly how much more transmissible it is but it has gone from being a small minority to a majority variant and that's clearly of concern.
"We know it partially evades the immunity generated by vaccines, thankfully if people have had two doses there's still a large amount of immunity remaining but it's not quite as much as before."
He added: "The key issue as to whether we can go forward is: will the surge caused by the Indian variant - and we do think there will be a surge - be more than has been already planned in to the relaxation measures?
"So it was always expected that relaxation would lead to a surge in infections and to some extent a small third wave of transmission - that's inevitable if you allow contact rates in population to go up, even despite immunity - (but) we can't cope with that being too large.
"In the next two or three weeks we will be able to come to a firm assessment of whether it's possible to go forward."
The seven-day infection rate in Wales is the lowest in the UK at 8.9, based on the number of new infections confirmed per 100,000 population in the week up to May 21, a rise on the 8.6 reported on Tuesday. Cases for your area here.
Monmouthshire now has the highest seven-day infection rate of anywhere in Wales with 20.1 per 100,000, followed by Bridgend with 18.4 and Newport with 15.5.
