London in the 18th century was riddled with syphilis, according to a new study, that found one in five people living in the capital had the sexually transmitted disease.
Georgian Londoners were also 25 times more likely than those living in rural Cheshire and north-east Wales to contract the disease, researchers found.
A major study by researchers from the University of Cambridge involved painstakingly scouring archives from the period including hospital admissions to calculate the rate of syphilis infection for men and women up to the age of 35.
One-fifth is a 'reliable minimum' estimate for just how prevalent the disease was in the capital, with authors suggesting syphilis was just the tip of the iceberg.
'A far greater number would have contracted gonorrhea or chlamydia than contracted syphilis in this period,' according to the historians behind the study.
In fact it is very likely that the vast majority of people living in the capital contracted an STI of one type or another while they were young, the team confirmed.
London is still the syphilis hotbed of the UK, in 2017 3,397 London residents were diagnosed with syphilis, accounting for nearly half of all cases in England.
The disturbing figures may not have surprised famed biographer James Boswell, who recorded up to 19 episodes of venereal disease in his diary from 1760 and 1786.
Boswell left a candid record of his many sexual exploits with prostitutes in London and the pain caused by contracting various STIs as a result of those 'exploits'.
The revelations formed part of the years of historical data digging carried out by study authors Simon Szreter from Cambridge and Kevin Siena from Trent University.
Boswell's helped to 'transform our understanding of the capital's population structure, sexual habits and wider culture as it became the world's largest metropolis', according to the team behind the study.
'It isn't very surprising that London's sexual culture differed from that of rural Britain in this period. But now it's pretty clear that London was in a completely different league to even sizeable provincial cities like Chester,' Szreter explained.
'The city had an astonishingly high incidence of STIs at that time', Szreter says.
'It no longer seems unreasonable to suggest that a majority of those living in London while young adults in this period contracted an STI at some point in their lives.'
'In an age before prophylaxis or effective treatments, here was a fast-growing city with a continuous influx of young adults, many struggling financially. Georgian London was extremely vulnerable to epidemic STI infection rates on this scale.'
For the study, that involved scouring through years of medical records, hospital admissions and even diary entries, the team said their calculations were 'very conservative' at every stage', so real figures were likely higher.
On experiencing initial signs of discomfort, such as a rash or pain in urination, most people in Georgian England hoped that they only had 'the clap' (gonorrhea) rather than 'the pox' (syphilis), the team said.
They would have begun by self-medicating with various pills and potions designed to treat gonorrhea - the most common of the STIs at the time.
However, for many, the symptoms got worse, leading to debilitating pain and fevers which they couldn't ignore.
Mercury salivation treatment was considered a reliable and permanent cure for syphilis but it was debilitating and required at least five weeks of residential care.
People with an STI had to pay for treatment at London's largest hospitals but could get help for free at specialist facilities and poor law infirmaries.
To maximise the accuracy of their estimates, Szreter and Siena drew on large quantities of data from hospital admission registers and inspection reports.They also used other sources to make numerous conservative estimates including for bed occupancy rates and duration of hospital stays.
Along the way, they excluded many patients to avoid counting the false positives that arise from syphilis's notoriously tricky diagnosis.
Of particular value to the researchers were surviving admissions registers from the late 1760s through to the 1780s for St Thomas's and Guy's Hospitals which consistently housed 20–30 per cent of their patients in 'foul' wards.
These were hospital wards reserved for residential treatment for the pox.
The researchers also drew on evidence for St Bartholomew's hospital; workhouse infirmaries; and two subscription hospitals, the Lock and the Misericordia, which also cared for 'foul' men and women.
Patients in London's foul wards often battled their diseases for six months or more before seeking hospitalisation.
This made it highly likely that the majority of patients they were counting in the records were suffering from significant protracted symptoms more characteristic of secondary syphilis than of gonorrhea, soft chancre, or chlamydia.
Szreter and Siena reached a final conservative estimate of 2,807 inpatients being treated for pox annually across all institutions in or around 1775.
They then divided this by the total population living in the catchment area for the various institutions they studied to get a 42.4 in 10,000 rate of infection.
When compared to existing data for Chester – which had a 12.2 in 10,000 rate of infection - and adjusted for the social differences – they converted London's crude rate into a comparable cumulative probability rate.
This suggested that while about 8 per cent of Chester's population had been infected by age 35, the figure for London was well over 20 per cent.
In 2017 the rate of syphilis diagnoses in London was 38.7 per 1,000 population and residents in all of London's 33 local authorities had someone diagnoses with the STI.
However, the figures aren't directly comparable as London is now a much more populous city and it is easier to diagnose the virus than it was nearly 250 years ago.
A major factor for the rates of syphilis in 18th century London is likely to have been the increasing movement of people through the city in this period.
Young women were particularly well represented among new arrivals to the city, and they were often placed in positions of domestic and economic dependence on mostly male employers.
The full 20 per cent chance of infection applies to individuals continuously resident in the capital from age 15 through to age 35.
While this applies to most Londoners, among the sizeable mobile minority of the capital's population, who were probably at most risk, some came and went and so spent only part of that most vulnerable period of their lives exposed to this risk.
The historians emphasise that STIs were particularly rife among young, impoverished, mostly unmarried women.
They were either using commercial sex to support themselves financially or in situations that rendered them vulnerable to sexual predation and assault.
They were also rife among two sets of men: poor in-migrant men, many still unmarried and on the margins of London's economy; and, a range of more established men like James Boswell, who were able to pay for private treatment.
'Syphilis and other STIs can have a very significant effect on morbidity and mortality, as well as fertility', Szreter explains.
'So infection rates represent a serious gap in our historical knowledge, with significant implications for health, for demography and therefore for economic history. We hope that our work will help to change this.'
'Understanding infection rates is also a crucial way to access one of the most private, and therefore historically hidden, of human activities, sexual practices and behaviours,' Szreter added.
Siena said the study suggests a significant number of young women were forced to engage in 'mercenary sex' to survive the city - rather than them being 'free spirits'.
The findings have been published in the Economic History Review.
SYPHILIS EXPLAINED: A BACTERIAL INFECTION MOST OFTEN CAUGHT THROUGH SEX
Syphilis is a bacterial infection that is usually caught by having sex with an infected person.
It spreads through close contact with an infected sore, which usually happens during vaginal, oral or anal sex.
Infected pregnant women can pass the STI to their unborn babies, which can lead to miscarriages or stillbirths.
Syphilis can also be spread by sharing needles with an infected person.
Symptoms are not always obvious and may eventually disappear.
These could include:
- Small, painless sores or ulcers on the penis, vagina, anus or around the mouth
- Blotchy red rashes on the palms or soles of the feet
- Small skin growths on women's vulvas or the anus
- White patches in the mouth
- Fatigue, headaches, joint pain, fever and swollen lymph nodes
If untreated, syphilis can spread to the brain or elsewhere in the body and cause disabilities or death.
Treatment is usually an antibiotic injection into the buttocks or a course of tablets.
People can reduce their risk by using condoms during sex, a dental dam (plastic square) during oral sex and avoiding sharing sex toys.