HIV prevalence among female sex workers has fallen sharply in the last 10 years, surprising even researchers.
The prevalence in Nairobi sex workers is now just three times that of the general population, down from about seven times 13 years ago.
It stands at 12 per cent, a great improvement from 2008 when 44 per cent of all female sex workers in the city were infected, a new study suggests.
This is a 67 per cent reduction after adjustment for known demographic and behavioural factors that could influence the results.
This study is published in the February edition of AIDS, a scientific journal owned by the International Aids Society, and further reported by the Aidsmap charity.
“HIV prevalence decreased over time in all age groups. This was particularly evident among female sex workers less than 25 years of age,” authors say.
Three authors are from the University of Nairobi’s Institute of Tropical and Infectious Diseases while the others are from Canadian universities.
They analysed anonymous data at seven different Sex Worker Outreach Programmes in Nairobi from a total of 33,560 women.
Prevalence among young sex workers under 25 years dropped from a high of 19 per cent in 2010 to five per cent.
This compares well with the national HIV prevalence, which stands at 4.9 per cent, according to the Kenya Population-based HIV Impact Assessment 2018 survey.
A separate study from Mombasa, published in the International Journal of STD & Aids in October last year, also shows a similar trend.
“From 1993 to 2016, an overall 30 per cent decrease in prevalence was noted with an average annual decline of three per cent,” this study shows.
Currently, about one in 10 female sex workers in Mombasa are infected with HIV, says the study, titled ‘HIV infections among female sex workers in Mombasa, Kenya: Current prevalence and trends over 25 years.’
The Nairobi study notes that no single intervention can be credited with the sharp fall.
However, the authors agree that increasing HIV awareness, testing and treatment played a major role.
It is also possible increased viral suppression in infected clients prevented spread to sex workers.
The Nairobi study shows in 2008, only 50 per cent of HIV positive sex workers had previously taken an HIV test, compared to 95 per cent in 2017.
In women who tested negative there was also an increase from 77 per cent to 98 per cent.
Condom use has increased significantly. Only 11 per cent of HIV-negative female sex workers with regular partners in 2008 reported their partners used condoms.
But by 2017, this rose to 75 per cent.
Among workers with casual partners, condom use every time was reported by 67 per cent of women in 2008 but increased to 90 per cent in 2017.
The researchers said one limitation could be that more sex workers at higher risk of contracting HIV were enrolled earlier in the study, with sex workers at lower risk joining later. They said this could partly account for the decrease seen.
They recommend despite the low prevalence, sex workers and their clients must still practice safe sex.