Friends and family will be able to hug and mix indoors from next week, while cinemas and museums can reopen, Boris Johnson is to confirm on Monday despite growing concerns over the spread of the India coronavirus variant.

Yat, scientists warned this weekend that cases are doubling in some areas where the variant, B1.617.2, has been detected. More deprived areas and those with large ethnic minority communities where vaccination rates may be lower are most affected, they said.

But at a press conference today the prime minister will hail the Covid vaccine rollout, with more than two-thirds of UK adults having had a first dose and a third now fully vaccinated. Just two deaths within 28 days of a positive test were reported on Sunday.

Johnson will confirm that the next stage in the easing of Covid restrictions for England will go ahead from 17 May. Indoor drinks and meals will be allowed for groups of up to six or two households, while cinemas, galleries and the rest of the accommodation sector will reopen.

International leisure travel will be possible, with some destinations given a “green light” enabling return without self-isolation, and ministers indicated that “intimate contact” will once more be permissible.

“The roadmap remains on track, our successful vaccination programme continues – more than two-thirds of adults in the UK have now had the first vaccine – and we can now look forward to unlocking cautiously but irreversibly,” Johnson said in comments released overnight.

Speaking on BBC One’s Andrew Marr Show on Sunday, the Cabinet Office minister, Michael Gove, said that the government wants to see families able to hug again. “As we move into stage three of our roadmap it will be the case that we will see people capable of meeting indoors. And without prejudice to a broader review of social distancing, it is also the case that friendly contact, intimate contact, between friends and family is something we want to see restored,” he said.

Scientists are concerned about the possible spread of variants as the country relaxes. The notification by Public Health England that one of three variants first seen in India is now “of concern”, with increased transmissibility, demonstrates the need for continued caution, they said. There is anxiety about the anticipated ending of mask-wearing in schools, where clusters of cases linked to the variant have been reported.

Prof Susan Michie, director of UCL’s Centre for Behaviour Change, talked of a mixed picture. If people carry on getting vaccinated at the current rate, it should be possible to keep transmission low, she said.

But the spread of the virus was very uneven. “We have pockets of high rates of transmission, especially in more deprived communities, and where you get high rates of transmission, you obviously also get the likelihood of variants that might undermine the vaccine programme,” said Michie.

Cases of the Indian variant are thought to be doubling every week. “There’s definite signs of community transmission in London. Now that’s obviously concerning, because we don’t yet know what effects it’s likely to have on our vaccine programme,” she added.

Paul Hunter, professor in medicine at the University of East Anglia, said it was “the Indian variant that is giving me most unease”. The Kent variant (B.1.1.7) had been collapsing in recent months but the Indian variant had been increasing quite rapidly. “I do worry that we will see cases increasing again soon when and if the Indian variant B.1.617.2 becomes dominant,” he said.

But it was difficult yet to know how serious an issue this was. “The signs are troubling but probably not yet strong enough to delay the next stage of lockdown easing. In particular we don’t know how severe the Indian variant will be in people who have been vaccinated,” he said.

Michael Head, senior research fellow in global health at Southampton University, said his personal view was that we could encourage larger outdoor gatherings but leave the reopening of indoor settings until all adult groups are vaccinated, which is expected by mid-July.

“Meeting friends and relatives outdoors is much lower risk. Personally, I’d be happier to spend two hours sat outdoors in a sports stadium with a few thousand spectators than I would be inside a cinema watching a film with 100 other people,” he said.

Michie said she thought the public should be given more information about the importance of ventilation indoors to prevent aerosol transmission. Hugs, as long as people did not breathe in each other’s faces, were not so risky, she said. “I think the issue about opening up all the indoor spaces, whether it’s pubs, restaurants, cinemas, theatres, etc, is the ventilation. I don’t know how that’s going to be communicated.”