ON a day when rollout of Moderna's shots began, Britain achieved a milestone of having offered all over-50s a first dose of Covid-19 vaccine.
The government said it is on track to give a shot to all adults by the end of July.
Britain has seen one of the world's quickest vaccine rollouts, behind only Israel in the proportion of its population receiving at least one dose of a Covid-19 shot.
"We will now move forward with completing essential second doses and making progress towards our target of offering all adults a vaccine by the end of July," prime minister Boris Johnson said in a statement.
Despite lower vaccine supplies in April than March, Britain has slowed down the pace of first doses, to ensure people in high-priority groups receive a second dose.
In a boost to vaccine supplies for first doses, the rollout of Moderna's shot in England begins on Tuesday, after first doses were given in Wales last week.
Johnson's office said that the government remained on track to offer all adults a shot by July 31. People in their late 40s are expected to be the next to be invited for shots, his office said, pending confirmation from vaccine officials.
The success of the vaccine programme has underpinned Johnson's roadmap out of lockdown, which on Monday (12) saw all shops and outdoor hospitality settings in England reopen, with some celebrating on the street into the evening.
Adding a note of caution to the optimism, the government announced an expansion of the so-called surge testing in the south London boroughs of Lambeth and Wandsworth to detect cases of the variant first found in South Africa.
There have been 74 confirmed and probable cases of the coronavirus variant, known as B.1.351, in the boroughs, and there is concern that vaccines are less effective against it.
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