People can still get sick after having both Covid jabs and pass it on to the people they love.
And if the high case rates sustain themselves, the chances of infection grow with them.
The Delta variant, which is now dominant in the UK, is also more infectious than its close relatives.
Medical professionals advise people to keep wearing their masks after they have completed their vaccine regimen.
Lawrence Young, Professor of Molecular Oncology at Warwick Medical School, said they go a long way to making the body’s respiratory entrances inhospitable for Covid.
He told the Huffington Post wearing a mask after vaccination is “still important”.
Masks stop people from getting infected, he said, by acting as a barrier and keeping “your nose warm and moist which also inhibits infection.”
The World Health Organisation (WHO) follows with its official advice.