The figures, from an Evening Standard analysis of NHS data, come amid growing concern that the vast majority of Covid patients in intensive care are unvaccinated.
Renewed efforts are underway to target three key groups — pregnant women, clinically extremely vulnerable people and children aged 12-15, who are believed to be spreading the virus between generations.
Last week the Standard revealed that as many as 2.7 million Londoners aged 16 or older may not have had their first jab.
Some council leaders fear the focus on booster jabs — which are proving hugely popular among the vaccinated population, with 1.5 million given in London so far — has distracted from “evergreen” efforts to encourage the take-up of first and second jabs.
But Pippa Nightingale, chief nurse for North West London NHS, told the Standard: “Every single vaccine that we give right now is just as important, whether it’s a booster or a first vaccine. If everyone had been [fully] vaccinated, we pretty much would be stopping any deaths or ITU [intensive care] admissions now.”
The NHS and councils are using local pharmacies, vaccine buses, community “champions” and direct phone calls to encourage the “vaccine hesitant” to come forward. GPs are hosting online question and answer sessions.
There are some signs that unvaccinated parents are coming forward after consenting to their children being inoculated at school.
About 40,000 first jabs a week are being given in the capital but more than half of these are in children aged 12-15.
Pregnant women account for one of the biggest unvaccinated groups, prompting efforts to reassure them that the jab is safe for them and babies.
The number of pregnant women in intensive care has doubled since the second and third waves of the pandemic. Across England, Wales and Northern Ireland, they made up 15 per cent of all Covid patients in critical care between May and July, with new mothers accounting for a further 13 per cent. Three pregnant women and 11 recently pregnant women died.
Overall, 73 per cent of patients admitted to intensive care were unvaccinated — rising to more than 90 per cent in the 18-29 and 30-39 age groups — according to this week’s ICNARC (Intensive Care National Audit & Research Centre) report.
The Standard’s analysis found that Westminster had the highest rate of unvaccinated adults (40 per cent of over 18s), followed by Kensington and Chelsea (39 per cent), Hammersmith and Fulham (38 per cent) and Camden (37 per cent).
Bromley had the lowest rate (17 per cent) followed by Bexley and Sutton (both 18 per cent).
Younger Londoners accounted for most of the unvaccinated population. By November 14, more than 436,000 people aged 30-34 and 400,000 in the 18-24 age group had not received a first dose. There were 384,000 unvaccinated in the 25-29 age group.
Ms Nightingale said the number of unvaccinated people was a “real concern”.
“Although we have given 3.5m vaccines in North West London, we have still got six per cent of over 40s not yet vaccinated,” she said. “Six per cent doesn’t sound like much but it’s 138,000 people.”
She added: “Only 54 per cent of pregnant women living in North West London have received any vaccine. “Vaccine hesitancy is more complicated in pregnancy because people think not just about themselves but their unborn child.
“What we do know now from the evidence is how safe it is to give [the vaccine] in pregnancy, and how vital it is, to prevent the mother being unwell, and to prevent death in pregnancy and also prevent the baby having to be delivered prematurely and potentially die as well.”
She said efforts were being stepped up to vaccinate children and teenagers. “These younger age groups are spreading it to household members,” she said. “It only takes a 12-year-old to go and visit their grandma at the weekend and there is a transmission made.”
Westminster council believes its vaccination rate may be higher than the official figures suggest because of the “churn” of residents moving in and out of the borough.
Anna Raleigh, director of public health in Westminster, and Kensington and Chelsea, said the current focus was on the booster campaign.
She added: “Nonetheless there is work we need to do, particularly to make sure that our most disadvantaged population can have access to vaccination.
“There is considerable work that is taking place within communities, and in areas where we are seeing lower levels of vaccination alongside higher [infection] rates.”
In Hackney, where the unvaccinated population tops 100,000 when the 16-17 age group is included, the council is trying to improve access to vaccines and provide “clear and trusted information”, including to the large Orthodox Jewish community.
Hackney mayor Phil Glanville told the Standard: “The number of unvaccinated residents in Hackney is deeply concerning and we must not lose sight of the fact that 100,000 people in the borough, over a third of our entire population, have not had their first dose of the vaccine.
“Clearly, if you are not vaccinated you are much more vulnerable to becoming seriously ill or dying from Covid-19 and this is most obviously reflected in our local hospital admissions.”
Will Huxter, director of NHS London’s covid vaccination programme, said: “With strong booster uptake and encouraging signs across the city of more people getting their first jab, I strongly urge anyone eligible for their first, second or booster jab who is yet to come forward to book online or head to a local walk-in centre, joining the many millions of Londoners already vaccinated against Covid.
“With over 400 vaccination sites across London, from pharmacists and walk in centres to places of worship, there are plenty of opportunities to get information, discuss concerns and get protected especially in time to see loved ones at Christmas.”