Long lines have formed at vaccination centres across England as people heeded the government's call for all adults to get booster shots to protect themselves against the Omicron variant, as the UK recorded its first death of a patient infected with Omicron.
In a televised announcement late on Sunday (local time), Prime Minister Boris Johnson said everyone aged 18 and up would be offered a third vaccine dose by December 31 — less than three weeks away, and a month earlier than the previous target.
Johnson said boosters would "reinforce our wall of vaccine protection" against an anticipated "tidal wave of Omicron". UK health authorities say Omicron cases are doubling every two to three days in Britain, and it will replace Delta as the dominant coronavirus strain within days.
The British government raised the country's coronavirus threat level on Sunday, warning that the rapid spread of Omicron "adds additional and rapidly increasing risk to the public and health care services".
Scientists in South Africa, where Omicron was first identified, say the variant may cause less severe disease than Delta but caution that it's too soon to be certain. Health authorities around the world are watching Britain closely to see what an Omicron surge looks like in a country with an older, more highly vaccinated population than South Africa's.
About 10 people are in UK hospitals with Omicron, and Johnson reported the country's first Covid-19 Omicron death on Monday.
"The idea that this is somehow a milder version of the virus, I think that's something we need to set on one side and just recognise the sheer pace at which it accelerates through the population," Johnson said as he visited a vaccination centre in London. "So the best thing we can do is all get our boosters."
The UK Health Security Agency says existing vaccines appear less effective in preventing symptomatic infections in people exposed to Omicron, though effectiveness appears to rise to between 70 per cent and 75 per cent after a third dose.
More than 80 per cent of people age 12 and up in Britain have received two vaccine doses, and 40 per cent of adults have had three. Giving the rest of adults boosters by the end of the month will be a huge challenge, requiring almost 1 million vaccine shots a day. Johnson acknowledged that many routine medical procedures would have to be postponed to meet the goal.
Some 750 soldiers and thousands of volunteer vaccinators will help give the jabs at doctors' offices, hospitals, pharmacies and pop-up vaccination centres.
While the online booster appointment system will not be open to under-30s until Wednesday, Johnson said any adult could show up at a walk-in centre to get a booster starting on Monday.
That caused a rush at big London vaccination clinics on Monday morning. The line for shots at St Thomas' Hospital, on the south bank of the River Thames in London, stretched across Westminster Bridge toward Parliament. At many clinics, people queued patiently despite being told they faced a wait of several hours.
At the Gordon Hospital walk-in clinic in central London, most of those lining up were in their 20s and 30s.
"It's only an hour and I can get a boost," said Sam Collins, 30. "It's a fair bit of time, but I've seen loads of other clinics on social media and things which have far longer queues."
He said he was "not especially" worried about Omicron, "but I'd just prefer to be triple vaxxed. Also my partner has just had a baby and she's not vaccinated, so if I can be extra vaccinated, then that will help."
The government's appointment-booking website struggled to keep up with demand, and also ran out of rapid at-home virus test kits, which have been distributed free to households during the pandemic. From Wednesday, people in England must show proof of vaccination or a negative test to enter nightclubs and other crowded venues.
Johnson's December 31 target applies to England. The other parts of the UK — Scotland, Wales and Northern Ireland — are also expected to speed up their vaccination campaigns.
While Omicron is spreading around the world, Britain may be especially affected because it ordinarily has high levels of travel to South Africa. The Omicron outbreak is also more visible in Britain because the UK is also a world leader in genomic sequencing, the technique used to identify and track new variants.
Researchers in the UK have sequenced about 13.3 per cent of all positive cases, compared with 3.8 per cent in the US, according to GISAID, which promotes rapid sharing of data on Covid-19 and the flu. While Iceland and Denmark have sequenced a greater percentage of their positive cases, the size of the UK's population and the scope of its outbreak mean that Britain has sequenced many more cases.
This surveillance provided key evidence that Johnson and his chief medical officers used in deciding to tighten pandemic restrictions and ramp up the UK's vaccination programme.
Johnson's Conservative government is requiring vaccine certificates to enter nightclubs and reintroducing restrictions that were lifted almost six months ago. Masks must be worn again in most indoor settings and as of Monday, people were urged to work from home if possible.
Many scientists say those measures are unlikely to be enough and are calling for tougher ones. But cafes, pubs and shops in city centres fear that plummeting numbers of commuters will hammer their businesses in the usually busy pre-Christmas period.
Johnson is facing a major rebellion from unhappy Conservative lawmakers when Parliament votes on the new virus restrictions on Tuesday. Dozens are expected to oppose the restrictions — especially vaccine passports, which they say are unfair and economically damaging.
The measures are still highly likely to pass with support from the opposition Labour Party.
Robert Read, a professor of infectious diseases at the University of Southampton, said it was still unclear how severe cases of Covid-19 from omicron would be but "the evidence is that Omicron probably requires much larger amounts of antibody in the blood in order to thwart the virus as much as possible".
"We need to get those third doses into as many adults as we possibly can, just in case this virus turns out to be a raging bull rather than a pussy cat," Read told radio station LBC.