Knowledge about and use of HIV pre-exposure
prophylaxis (PrEP) has greatly increased over the past few years in San
Francisco, and surveillance estimates suggest that some 12,500 people are now on PrEP, most of them gay
and bisexual men, according to a presentation at the HIV
Research for Prevention conference (HIVR4P) last week in Chicago.
PrEP use has increased dramatically over
the past few years as clinical trials and demonstration projects continue to
confirm its safety and efficacy. Studies of gay and bisexual men have shown
that Truvada (tenofovir/emtricitabine)
reduces the risk of HIV infection by more than 90% if used consistently, with no new
infections seen among people who take it at least four times a week.
It has been
difficult to estimate how many people have used Truvada for PrEP, as this information is not centrally collected. A
reported survey of retail pharmacies by Gilead Sciences
found that more than 79,000 people in the US have taken PrEP over the past four
years, but this does not include
people who received PrEP through various studies or through public or private programmes that do not report their numbers.
San Francisco is known to be at the
forefront of widespread PrEP adoption. The city's large and well-informed gay
community has promoted its use, and supportive politicians and public health
officials have provided resources for expanding PrEP access as part of the
city's 'Getting to Zero' initiative.
Susan Scheer of the San Francisco Department of Public Health (DPH) presented findings from an analysis
of knowledge about PrEP and trends and disparities in PrEP use among people
at risk for HIV in the city.
The researchers collected data from people seen at
City Clinic (a large DPH sexually transmitted disease clinic), DPH-funded
primary care clinics and Kaiser Permanente San Francisco. In addition, they
looked at community-based self-reported data from the National HIV Behavioural
Surveillance (NHBS) system, City Clinic patient interviews, clients at
community-based HIV testing sites and a survey by the Stop AIDS Project, now
part of the San Francisco AIDS Foundation's Strut health and wellness centre
for gay, bisexual and trans men.
While only 19% of City Clinic clients knew about PrEP
in 2011 – the year after results from the pivotal iPrEx trial were published – this increased to more than 80% by 2014. Data from 2016 show that
although around 90% of clients at City Clinic and Strut were knowledgeable
about PrEP, this fell to 71% of those visiting community HIV testing sites.
Turning to self-reported use, in 2014 10%
of NHBS respondents, 14% of City Clinic clients and 16% of Stop AIDS survey
respondents said they had used PrEP. By 2016, 29% of City Clinic clients and
44% of Strut clients said they had used PrEP, but this fell to just 11% at
community testing sites.
Several studies have found that gay men of colour and
women are less likely to use PrEP compared to white gay men, and this was
reflected in the data about PrEP knowledge and reported use.
Among City Clinic and Strut clients, PrEP awareness
was high across all racial/ethnic groups: around 85% of African Americans, 87%
of Latinos, 89% of Asians and 92% of white people. But at community testing sites the
disparity was greater: 50% of black people versus 88% of white people, with Latinos and
Asians falling in between.
Overall, people under age 18 and over 50 were less
likely to know about PrEP. Only about a third of cisgender (non-transgender) women
at City Clinic and the testing sites knew about PrEP, although awareness was
high among transgender women and men (87% and 84%, respectively).
PrEP use followed a similar pattern. Black
clients were somewhat less likely to report PrEP use than white clients: 25% vs 31% at
City Clinic, 40% vs 48% at Strut and 6% vs 10% at community testing sites.
Latinos were about as likely to use PrEP as white people. Again, people under 18 and
over 50 were less likely to report PrEP use. Only about 3% of cisgender women
did so, compared with roughly a third of cisgender men and trans women and men.
Although African Americans accounted for
17% of new HIV infections in San Francisco in 2015, the proportion of black
PrEP users ranged from less than 5% to just over 10% at the various sites. PrEP
use among Latinos and Asians roughly matched their share of new HIV infections,
while use among white people exceeded their 42% share of new infections.
Kaiser and Strut were disproportionately
more likely to see white PrEP users and less likely to see people of colour.
DPH primary care clinics came closest to having their PrEP users match the
racial/ethnic distribution of new infections in the city, and were the only
sites to serve a substantial number of female PrEP users.
Dr Scheer explained that the DPH does not
do name-based PrEP surveillance, PrEP prescriptions are not reportable by
providers or pharmacies, and there are no standard indications or diagnostic
codes for PrEP. Instead, health officials must rely on sentinel site
surveillance, provider logs, and surveys of local gay men, clinic clients and
people receiving HIV tests. As such, estimates of the total number of PrEP
users are at best approximations.
“Measuring PrEP knowledge and use is difficult,” Dr Scheer said. “There
is no formal surveillance system for PrEP like there is for HIV. A CDC study
presented at the HIVR4P conference found that only 13% of health departments
across the U.S. are even attempting to monitor PrEP use.”
Current estimates suggest that
approximately 12,500 San Franciscans are now on PrEP.
“The 12,500 is an estimate – it does not come from
adding up individual sites that have reported PrEP use to us,” Dr Scheer
explained. “Pulling together existing data from community-based sources and
clinics prescribing PrEP and comparing this to the estimates of PrEP-eligible
persons – for example, 25% of men who have sex with men (MSM) reporting PrEP
use in 2016 and an estimated 50,000 HIV-negative MSM in San Francisco – we
estimate that about 12,000 to 13,000 people are now using PrEP.”
“Obtaining actual numbers from sites is difficult
– people go on and off PrEP, so determining current users is hard, sites often
can only guess at the numbers on PrEP, and some sites can't pull the
information from their medical records and therefore don't even provide an
estimate to us,” she added.
A recent informal survey of
large PrEP providers found that Strut had reached 1000 prescriptions and
Kaiser had hit 1800 by June 2016, most of them to gay and bisexual men. In addition,
over 500 people had started PrEP at City Clinic (not including clients
who rolled over to regular prescriptions following enrolment in the PrEP Demo
Project) and about 220 people were on PrEP at the primary care clinics.
The DPH aims to have 15,000 people on PrEP
by 2017 and around 2500 new PrEP starts next year. But Dr Scheer emphasised
that not all populations at high risk of HIV are being reached by current PrEP
programmes, particularly young people, African Americans and women.
“PrEP knowledge and use in San Francisco has been rapidly rising,” Dr Scheer
told Aidsmap. “It is important to monitor PrEP use so that gaps in
knowledge and use can be identified and resources can be used to target those
not currently being reached. We
want to be a city where everyone who would benefit from PrEP knows about it and
has equal and easy access to it.”