London, May 16 : The next stage of lockdown easing in England slated for Monday should be approached the "with utmost caution", a UK public health expert warned. Richard Jarvis, co-chairman of the British Medical Association (BMA) public health medicine committee, said on Saturday that "key segments of the population" were still not vaccinated against Covid-19, Xinhua news agency reported. "It is a real worry that when further measures lift on May 17, the majority of younger people, who are often highly socially mobile and could therefore be most at risk of a more infectious strain, are not yet vaccinated," he told the BBC. Those people in that age group had seen the highest rates of positive tests throughout the pandemic but would now be able to mix in larger groups indoors "without many of the mitigations that have helped to push infection rates lower and lower since the start of the year", he said. "We are urging the public, and young people in particular, to take a cautious approach to social and physical contact, to continue practising 'hands, face, space' and to meet outdoors wherever possible," he added. The expert's warning came after Britain witnessed a spike in cases of the coronavirus variant first detected in India. The UK government's Scientific Advisory Group for Emergencies (SAGE) has said the relaxation on Monday could "lead to a substantial resurgence of hospitalisations, similar to, or larger than, previous peaks". The scientists said there "may be some reduction in protection" when it comes to the current vaccines. However, Prime Minister Boris Johnson said on Friday that the spread of the India-related variant, known as B1617.2, would not affect the scheduled easing of lockdown in England from Monday. He said there was "no evidence" to suggest the current vaccines would be less effective against the strain. From Monday, pubs, bars and restaurants in England will be permitted to open indoors, while indoor entertainment will also resume, including cinemas, museums and children's play areas. People in England will be allowed to meet outdoors in groups of up to 30 people, and meet indoors in groups of up to six or as two households. Meanwhile, all remaining accommodation including hotels, hostels and B&Bs can reopen from May 24, according to Johnson. The British government's roadmap is expected to see all legal limits on social contact to be removed on June 21. /IANS