An Orthodox Jewish community in London has one of the world’s highest rates of Covid-19 past infection, according to a study that points to crowded housing and socio-economic deprivation as possible reasons for the increased prevalence.

The rate of past infection, known as seroprevalence, in one Orthodox Jewish community of roughly 15,000 people was found to be 64 per cent, according to researchers at the London School of Hygiene and Tropical Medicine.

By contrast, seroprevalence is believed to be 7 per cent across the UK and 11 per cent in London, the Office for National Statistics has estimated.

“The take home is how extreme the disparity in infections is. This is not a virus that is hitting people equally,” said Rosalind Eggo, an infectious disease modeller at the school and one of the report’s lead authors.

Prof Eggo cautioned: “It’s not safe to say that having reached this number [it] means that we’ve achieved herd immunity,” adding that it was not yet known “if there’s any benefit” to such high levels of previous infection.

A growing body of evidence has shown that black, Asian and minority ethnic (Bame) groups have experienced much more severe outcomes during the pandemic than Caucasian groups, and researchers are busy trying to parse what factors might be driving the disparity.

There is no directly comparable data on other Orthodox Jewish communities in the UK, in part because it is rare to gain access of this kind to do scientific research. However, studies from Israel have found markedly higher rates of past Covid-19 infection in Orthodox communities compared with other groups of a similar socio-economic profile. New York has also reported higher rates of infection and large clusters among its Orthodox Jewish communities.

The London School of Hygiene and Tropical Medicine report concluded that, while the precise reasons for high levels of past infection in the studied Jewish community were unclear, data from other sources suggested that lower socio-economic status, the need to travel to work and a greater burden of pre-existing comorbidities, may all contribute to increased risk of acquiring the virus.

Bar chart of mortality rate per 100,000 population, March 2 to May 15 showing Jewish men and women had highest death rates in first wave

The highest seroprevalence was 74 per cent in working-age adults and older children, according to the study that involved 343 households and 1,800 individuals between November and December 2020.

More than a quarter of young children, under the age of five, and half of primary school-aged children were found to have previously had the virus.

The community, which commissioned the study after becoming concerned at the high infection rate, did not respond to its findings. The researchers asked that it not be named to avoid broader social tension.

In 2020, Public Health England found that there were higher rates of death from Covid-19 in those self-identifying as Jewish, with an age standardised mortality rate for Jewish men over 65 years of 759 per 100,000 people, nearly double that of Christians.

“There are obvious parallels to other community groups,” said Michael Marks, professor of infectious disease at the London school and also a lead author on the study. He noted that “house size seems like a plausible major player”.

Orthodox Jewish families tend to have much larger households than the UK average, with roughly five to six individuals per home, compared with 2.3 across the UK. The median population age of the community was 14 years old, compared with the UK median of 40.

The Orthodox Jewish community in Stamford Hill, in north London, came under scrutiny last week when it emerged that several large weddings had taken place, in direct contravention of national laws, including one with 150 guests.

However, Prof Marks pushed back against the idea that higher rates of infection in the Orthodox community that he studied could be explained by rule-flouting and emphasised that members of the community did appear to have largely followed the rules through 2020, according to self-reporting of social activity. “The shape of the curve during wave one shows people did curtail their interactions,” he said.

There are several Orthodox Jewish communities in the UK, estimated to total somewhere between 40,000 and 60,000 people, mostly situated in London, Manchester and Birmingham.

The only community found to have a similar prevalence of Covid-19 is the city of Manaus, in the Brazilian Amazon region, where the proportion of the 2m population estimated to have been infected was 76 per cent by October of last year.