A Covid vaccine being administered in London, which has some of the least protected areas in England

Government’s ‘Get boosted now’ slogan means little in areas where up to 30% of people have had no vaccine at all

In the Newtown ward of central Birmingham, the government’s “Get boosted now” slogan means nothing to half of over-16s, because they have not had any vaccination against Covid at all.

It is a similar story in Westminster and Camden in London where among the over-12s, 30% have not had a single jab. In Nottingham, a quarter of the whole population face the coming Omicron “tidal wave” unvaccinated.

The vaccination scramble is not just about boosters but about persuading millions to get any jab at all.

“Omicron will unevenly hit the least protected,” said Jim McManus, the president of the Association of Directors of Public Health. “We have two jobs: to get the vaccines into as many arms as possible and really get into the communities with the worst uptake.”In Birmingham, one of the least vaccinated groups is Chinese 18- to 29-year-olds, who, according to the city council’s public health director, Dr Justin Varney, have been so heavily influenced by anti-vax messaging on Chinese social media that three out of four are not vaccinated.

Across the city, 42% of under-40s are not vaccinated – more than 200,000 people, including more than 70% of Caribbean people aged under 40.

Varney said vaccination clinics are being set up in the Bullring and Fort shopping centres and said a key problem was reaching younger people, who do not see the virus as life-threatening and will not take time off work for jabs if employers do not pay them.

The council is telling bosses to “view this like a chemotherapy appointment; it is really important,” Varney said.

McManus, who is also the director of public health for Hertfordshire, said the booster programme needed to be matched by a push to reach less-vaccinated groups, which analysis shows includes poorer, younger and more ethnically diverse communities.

In a previous article, experts told the Guardian that London’s figures could look worse than they were because of the capital’s highly mobile population, with many people moving home without deregistering from a GP.

London also has a younger-than-average population, and younger age groups have had less time than older people to get vaccinated.

Across England, just under 84% of people who live in the most deprived fifth of areas have had at least one dose, while this rises to more than 92% in the least deprived, figures from government deprivation data showed.

McManus said local health teams needed to offer transport, recruit community activists and even use contact tracing skills to contact unvaccinated people.

One of the least protected areas is Camden in north London where 30% of people have no vaccine protection. The public health director, Kirsten Watters, said on Wednesday she was “concerned for those residents who have not yet had their first or second dose and [I] urge them to come forward”.

The need for a push into harder-to-reach communities comes as the UK Health Security Agency reported that Omicron is now the main strain in London.

Fifty-two percent of a sample of new coronavirus cases in London with specimen dates for 11 and 12 December were found to have S-gene target failure – a way of detecting the likely presence of the latest variant.

Its penetration across England is now estimated at 24% but the spread is uneven, with only 6% of Covid cases likely to be Omicron in the north-east.

London’s relatively low vaccine protection is one reason Omicron has become dominant so rapidly, said Prof Azeem Majeed, chair in primary care and public health at Imperial College London. The size of the city’s international airports, number of international visitors and its dense, often overcrowded population were other reasons.“The challenge we face in London is significant but every dose of vaccine given to someone is a brick in that wall of protection,” said Prof Kevin Fenton, the London regional director of public health at the Office for Health Improvement and Disparities. “We need all of London to get full vaccine protection as soon as possible – one dose, two doses and get boosted.”

A spokesperson for the London mayor, Sadiq Khan, said projects were under way in the capital to work closely with “community stakeholders, schools and faith leaders to deliver communication campaigns to promote the vaccine to all Londoners, especially those targeted by disinformation around vaccines, and supporting the NHS to open walk-in centres for Londoners regardless of immigration status and GP registration”.

The capital has the highest proportion of the UK’s migrant population, who are less likely to be registered with a GP and some, with uncertain immigration status, are reluctant to share the personal information required to get jabbed.

“The mayor continues to urge all Londoners who are eligible for their vaccine doses to come forward as soon as possible to protect themselves and their loved ones,” the spokesperson said.