Researchers found no evidence to suggest that PrEP use is associated with increased risk for STIs.
People who take HIV prevention drugs do not engage in
riskier sex, which may expose them to other sexually transmitted infections (STIs).
Health officials had always feared that users would feel
protected enough to take greater sexual risks, potentially fuelling a rise in
STIs such as gonorrhea and syphilis in Kenya.
The fears were more palpable after Kenya last month
introduced Lenacapavir, the once-in-six-months anti-HIV injection.
But a new study in Kisumu suggests those fears are largely
unfounded.
Researchers in Kisumu followed about 650 women, 60 per cent
of them taking oral pre-exposure prophylaxis (Prep) to prevent HIV, and the others
not taking any, for 12 months until February 2024.
The findings published this week in the PLOS Medicine journal
indicate that women who used Prep did not engage in riskier sex and did not
experience higher rates of STIs than women who did not take the drug.
“During the 12 months of follow-up, there was no association
between frequency of condomless sex at the last sex and PrEP use consistency
through six months,” researchers said in their report, titled “Oral preexposure
prophylaxis use and the risk of bacterial sexually transmitted infections and
HIV among African women.”
They added: “We found no evidence to suggest that PrEP use
is associated with increased risk for STIs among African women at elevated risk
for HIV.”
Similarly, STI infection was reported only in 12
women who were consistently on PrEP, in 17 women who were inconsistently on
PrEP and in 25 women who never used PrEP at all.
The researchers are from Kenyatta National Hospital, the
University of Washington, the Fred Hutchinson Cancer Centre, and McGill
University, Canada.
The women were recruited at family planning clinics. They
were all believed to be at substantial risk of HIV infection and were offered
PrEP pills, but only 60 per cent (about 390) agreed.
Over the 12 months, researchers regularly tested them for
HIV, chlamydia and gonorrhoea.
The infection rate of STIs was almost identical among women
who used PrEP and those who did not, suggesting the medication itself did not
increase STI risk.
The findings help address a long-running debate about what
scientists call risk compensation. This is the idea that people who feel
protected from HIV might engage in riskier sex, potentially increasing exposure
to other infections.
However, this study suggests PrEP users may be more cautious
overall because they consider themselves to be at a higher risk of HIV and
STIs. They also receive more counselling during PrEP-related medical visits.
More striking still was the drug’s effectiveness against HIV
itself. During the year-long follow-up, only four women acquired HIV. Three of
those infections occurred among women who had declined to start PrEP.
“No HIV infection
occurred in women reporting consistent PrEP use, but 75 per cent of all new HIV
infections occurred in women who declined to initiate PrEP, representing a
tragic missed opportunity for HIV prevention,” the researchers said.
PrEP works by placing antiretroviral medicine in the
bloodstream before exposure to HIV. If the virus enters the body, the drugs
block it from establishing an infection. When taken consistently, the pills can
reduce the risk of acquiring HIV by more than 90 per cent.
The National Aids and STIs Control Programme (Nascop) last
month introduced lenacapavir, a long-acting injectable form of PrEP that
protects against HIV for six months.
It was rolled out in Nairobi on February 26, and will be followed by Migori and Busia on
March 12. Siaya and Mombasa will launch on March 13, then Homa Bay. Additional
launches are scheduled in Machakos, Nakuru, Kilifi and Kakamega on March 26,
with Kisii and Kajiado also expected to introduce the prevention injection.
Public health experts believe long-acting options could
transform HIV prevention by removing the challenge of remembering daily
medication.