AIDS Research and Therapy

Lindman et al. AIDS Res Ther (2020) 17:33

https://doi.org/10.1186/s12981-020-00290-3

RESEARCH Open Access

The HIV care continuum and HIV‑1 drug

resistance among female sex workers: a key
population in Guinea‑Bissau
Jacob Lindman1* , Mamadu Aliu Djalo2, Ansu Biai3, Fredrik Månsson4, Joakim Esbjörnsson4,
Marianne Jansson5, Patrik Medstrand4, Hans Norrgren1 and the SWEGUB CORE group

Abstract
Introduction: Female sex workers (FSW) are considered a key group for HIV transmissions in sub-Saharan Africa.
The HIV Care Continuum and HIV drug resistance (HIVDR) among FSW has not been well studied in most countries
in West Africa. In the current study we describe the HIV Care continuum and prevalence of HIVDR among FSW in
Guinea-Bissau.
Methods: A venue-based recruitment and peer-referral of FSW was used in seven cities in Guinea-Bissau from Octo-
ber 2014 to September 2017. We administered a questionnaire, performed discriminatory HIV-testing and collected
blood specimens for CD4 count, viral load and HIVDR genotyping.
Results: The survey included 440 FSW. The overall HIV-prevalence among FSW was 26.8%. Of the HIV-1 (HIV-1 single-
or dually HIV-1/HIV-2) infected FSW (N = 104), 58.7% were previously diagnosed with HIV-1 at enrolment and 41.4%
reported taking antiretroviral therapy (ART) compared to 28.6% of the HIV-2 single-infected FSW (N = 14). Among
HIV-1 infected FSW on ART (N = 43), 55.8% were virally suppressed (< 1000 copies/ml) and of all HIV-1 infected FSW,
29.8% were virally suppressed. Among ART experienced FSW (N = 22), 50.0% had HIVDR. HIVDR was also found in
9.4% of treatment naïve FSW (N = 53).
Conclusion: The majority of FSW who knew their HIV status received ART, however a large proportion of FSW were
not aware of their HIV positive status. This translated into a great majority of the HIV-infected FSW not being virally
suppressed. Amongst treatment naïve FSW nearly a tenth had HIVDR, suggesting that sexual transmission of HIVDR is
occurring in this at-risk-population.
Keywords: Antiretroviral therapy, HIV care continuum, HIV seroprevalence, Sex workers, Africa, Drug resistance
mutations

Introduction Africa was recently estimated to be 20.1% [2]. Antiret-

Female sex workers (FSW) play a key role for the trans- roviral therapy (ART) not only dramatically reduces
mission of HIV in sub-Saharan Africa [1]. The over- HIV morbidity and mortality, but also eliminates
all HIV prevalence among FSW in West and Central infectiousness of treated HIV-infected individuals—
referred to as treatment as prevention [3]. However,
if individuals living with HIV should benefit from
*Correspondence: jacob.lopatko_lindman@med.lu.se ART, they need to know that they are HIV infected, be
1
The Department of Clinical Sciences Lund, Lund University, linked to HIV care, and receive and adhere to effective
Infektionskliniken Skånes Universitetssjukhus Lund, Hälsogatan 3, 221
85 Lund, Sweden
ART. A systematic review of sub-Saharan African HIV
Full list of author information is available at the end of the article treatment programs including over 58,000 patients

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Lindman et al. AIDS Res Ther (2020) 17:33 Page 2 of 11

diagnosed with HIV showed that linkage from HIV Methods

diagnosis to HIV care was poor [4]. In Guinea-Bissau, Data collection
the national ART program was initiated in 2005 and This cross-sectional study was designed and imple-
according to UNAIDS about 49% of eligible women mented through a collaboration between Lund Univer-
aged 15 and over were receiving ART in 2018 [5]. sity in Sweden, the National Public Health Laboratory
Unfortunately Guinea-Bissau has shown to be a coun- (LNSP) in Guinea-Bissau, and Environmental Action in
try with generally poor ART adherence. In a report the third world (ENDA—a non-governmental organiza-
from an HIV clinic in the capital Bissau, between 2005 tion in Guinea-Bissau).
and 2012, more than half of the patients were lost to Inclusion of participants took place between October
follow-up during the study period [6]. Side effects, 2014 and September 2017. The inclusion criteria were
food insecurity and travelling have been proposed as being biologically female, ≥ 16 years old, self-reported
main barriers to ART non-adherence in Guinea-Bissau engagement in selling sex the last 12 months and giving
[7, 8]. As FSW are a marginalized group who are often oral and written informed consent to participate in the
stigmatized by health workers and also highly mobile, survey. Participants in the capital Bissau were included
there is reason to believe that the disengagement from through venue-based sampling at nine different venues,
care could be even higher in this key population in which has documented success for identification of hid-
Guinea-Bissau [9, 10]. A meta-analysis and systematic den populations [13, 19]. Participants in six cities outside
review of FSW in low-and-middle-income-countries Bissau were identified through peer-based chain-referral
estimated that current ART use among HIV-infected at one to four different venues depending on the size of
women was 39.2% (95% confidence interval (CI) 27.2– the city (14 different venues in total) and were required
52.9%) [11]. However, the report also highlighted the to come to a mobile clinic at daytime. Peer-based chain-
lack of data. The HIV care continuum is an important referral has previously been used to include FSW in stud-
framework to cross-sectionally describe the engage- ies in this region [19]. Participants were reimbursed for
ment in HIV care and treatment on a population level participating in the study ($2.67).
[12]. Previous studies among FSW in Malawi and Zim- A team of one trained nurse, one social worker and
babwe have found large numbers of drop-outs from one driver undertook the data collection. Interviewer-
the HIV care continuum [13, 14]. As more people are administered questionnaires was used to obtain informa-
starting ART the risk of HIV drug resistance (HIVDR) tion on demographics, HIV testing history, HIV care and
mutations increases [15]. Various factors drive the treatment engagement, sex work, sexual behavior and
emergence of HIVDR including poor adherence and condom use. Self-reported ART adherence was assessed
logistical barriers [15, 16]. Even when adherence by the visual analog scale (VAS) [20]. For the VAS, study
results in viral suppression HIVDR mutations may be participants were presented with line anchored at 0%
acquired through multiple infections and sexual acqui- and 100% and given examples of what 0%, 50% and 100%
sition of transmitted drug resistance. The WHO´s adherence represented. They were then asked to assess
2017 drug resistance report showed that levels of pre- their ART adherence for the last 4 weeks [20]. Good ART
treatment drug resistance (PDR) were increasing in adherence was defined as taking ≥ 90% of the daily medi-
low and middle income countries between 2014 and cine doses [20].
2016 [17]. This increase was mostly driven by increas- All women underwent venous blood sampling in a
ing levels of non-nucleoside reverse transcriptase mobile clinic and were screened on site with an HIV-
inhibitors (NNRTI) resistance which are currently antibody rapid test, Determine HIV-1/2 (Abbott Diag-
used in many sub-Saharan countries as first-line ART nostic Division, Hoofdorp, Holland). The blood samples
regimens for HIV-1, including Guinea-Bissau [15]. were stored in room temperature until transportation
A recent study of HIV-1 infected pregnant women in back to LNSP in Bissau the same day. At LNSP, a con-
Guinea-Bissau reported a 10.4% prevalence of PDR to firmatory discriminatory HIV test was performed using
NNRTI [18]. There is currently little information on Immunocomb HIV1/2 BiSpot (Orgenics, Yavne, Israel)
the HIV care continuum from diagnosis to viral sup- until September 2016, and thereafter Geenius 1/2 con-
pression and emergence of HIVDR among FSW in firmatory assay (Biorad, Marnes-al-Coquette, France) as
West Africa. Without such estimates the unmet needs the production of Immunocomb ceased. Immunocomb
of this population with which to guide treatment pro- and Geenius has been evaluated in parallel towards abil-
gramming is difficult to assess. Here, we report the ity to discriminate between HIV-type [21]. CD4 meas-
HIV Care Continuum and HIVDR among FSW in urement was obtained using the FACSPresto-Near
seven cities in Guinea-Bissau. Patient CD4 counter (Becton–Dickinson, NYSE:BDX,
USA) [22]. Plasma was then separated from whole blood
Lindman et al. AIDS Res Ther (2020) 17:33 Page 3 of 11

and until March 2016 all samples were transported on program (https​://hivdb​.stanf​ord.edu/hivdb​/by-mutat​
dry ice for HIV-1 viral load (VL) measurement and drug ions/) [29].
resistance genotyping at the Section of Clinical Virol-
ogy at Lund University, Sweden (please see below for Statistics
details). From March 2016, plasma HIV-1 viral load The Chi square test was used for categorical variables
quantification was performed using GeneXpert at LNSP and the two-tailed Mann–Whitney test U test for con-
in Bissau [23]. The results of CD4 measurements and VL tinuous variables. Trends in change of seroprevalence of
measurements were provided to participants at the next HIV was analyzed by Cochran-Armitage test for linear
visit at the mobile clinic where the study nurse assisted trend adjusted for age. FSW were defined as virally sup-
with interpretation of the results. All HIV infected FSW pressed with an HIV-1 VL < 1000 copies/ml [30, 31]. The
were referred to an HIV treatment clinic of their choice continuum outcomes were characterized using two dif-
together with their results for follow-up examination and ferent approaches; using all HIV-1/dual-infected FSWs as
treatment per national guidelines. the denominator or by using HIV-1/dual-infected FSW
achieving the prior step in the continuum as the denomi-
nator. Logistic regression was used to assess predictors of
HIV‑1 plasma viral load determination and drug resistance outcomes in the HIV care cascade. Due to sample size,
genotyping we were only able to investigate diagnosed HIV infection
HIV-1 viral load was prior to March 2016 determined vs. undiagnosed HIV infection. Covariates were assessed
using an in-house TaqMan quantitative PCR (qPCR) with in univariate and multivariate analysis. Covariates con-
primers and probes as described [24]. qPCR was done sidered for inclusion in the multivariate model were age,
using the ABI StepOnePlus System (Applied Biosystems) region, education, condom use, number of clients last day
and the SuperScript III Platinum One-Step qRT-PCR Kit of sex work, alcohol consumption and number of chil-
(Invitrogen) according to the manufacturer’s instruc- dren. The final model was derived from an initial explan-
tions. Polymerase chain reaction (PCR) conditions were atory model with all variables included. Models were
as follows: 50 °C for 10 min and 95 °C for 2 min, followed compared using likelihood ratio tests and Aikaki´s infor-
by 40 cycles of 95 °C for 15 s, and 60 °C for 45 s. Stocks mation criterion. In the final model the most important
of HIV-1 strain IIIB which had been quantified by elec- variables—age, region, education, condom use—were
tron microscopy (Advanced Biotechnology Incorporated, included. Data were managed in EPI INFO version 7.14
Columbia MD), were used as standards. Known virus and analyzed by STATA 13 [32, 33].
copy numbers were spiked into HIV-negative human
plasma and extracted as previously described [24]. The Results
qPCR assay had a limit of quantification of five RNA cop- During the study period 847 women visited the mobile
ies/qPCR reaction with a linear range between 1­ 06 and 5 clinic. Among them, 490 women consented to partici-
RNA copies/reaction. pate in the study but 50 women did not engage in sex
HIV-1 drug resistance genotyping were determined as work according to our definition and were not included
follows: HIV-1 RNA was extracted from blood plasma, in the study. Thus a total of 440 women were included
and HIV-1 pol sequences were amplified by RT-PCR and between October 2014 and September 2017, 63.2% of
nested PCR as described [25]. The final length of all the the women were included in the capital Bissau. Figure 1
HIV-1 pol sequences following removal of regions corre- shows the flowchart of the included study participants.
sponding to the primers, editing and alignment was 1035 The median age was 28 (Interquartile range (IQR) 22-35).
bases, corresponding to nucleotide positions 2268–3302 The overall HIV-prevalence at inclusion was 26.8% (95%
of HXB2 (GenBank accession number K03455), cover- CI 22.7–31.2, n = 118). The total prevalence of HIV-1
ing positions 6-99 of the protease and positions 1-251 single-infection, HIV-2 single-infection and HIV-1/2
of the reverse transcriptase regions. The presence of dual infection was 20.5% (95% CI 16.8–24.5, n = 90),
drug resistance mutations (DRM) was assessed using the 3.2% (95% CI 1.8–5.3, n = 14) and 3.2% (95% CI 1.8–5.3,
Stanford Genotypic Resistance Interpretation Algorithm n = 14), respectively. The overall HIV-prevalence over
[26]. DRM in self-reported treatment naïve individuals the 3-year study period decreased over time from 32.6%
were examined according to the calibrated population (95% CI 25.6–40.1) between October 2014 and Septem-
resistance tool v6.0 beta (http://cpr.stanf​ord.edu/cpr. ber 2015 (N = 172), 26.0% (95% CI 17.8––35.7) between
cgi), based on the WHO surveillance transmitted drug October 2015 and September 2016 (N = 100), to 21.4%
resistance mutation list of 2009 [27, 28]. DRM in FSW (95% CI 15.4-28.4) between October 2016 and Septem-
on current ART and DRM in FSW reporting treatment ber 2017 (N = 168) (p = 0.02 comparing the HIV preva-
discontinuation was assessed using The Stanford HIVdb lence over three time periods). After age-adjustments no
Lindman et al. AIDS Res Ther (2020) 17:33 Page 4 of 11

440 included FSW

HIV-negave HIV-1 HIV-2 HIV-1/2

single-infecon single-infecon dual-infecon
n=322 n=90 n=14 n=14

HIV-1
Seroconverters^ VL ≥1000 VL <1000 VL ≥1000 VL <1000
n=64 n=26 n=9 n=5
n=3

Genotyped for Genotyped for Genotyped for Genotyped for Genotyped for
HIVDR HIVDR HIVDR HIVDR HIVDR
n=3 n=63 n=9 n=9 n=0
Fig. 1 Flowchart of the study population. HIVDR, HIV drug resistance mutations; VL, Viral load. ^Three individuals seroconverting from
HIV-seronegative to HIV-1 seropositive status during the study period

statistically significant declining trend could be detected younger FSW (< 30 years) were more likely to be previ-
(p = 0.58 comparing the HIV prevalence over three ously undiagnosed (adjusted odds ratio (AOR) 2.7 (95%
time periods). Table 1 presents summary characteris- CI 1.2–6.5, p = 0.02), and there was some evidence that
tics of HIV-infected participants stratified by HIV type FSW residing outside Bissau were more likely to have
and HIV-negative participants. HIV-1 single-infected an undiagnosed HIV infection (AOR 2.7 (95% CI 1.0–
FSW were younger (median age 30 years IQR 25–37) 6.8, p = 0.05)). More importantly, an unknown HIV
compared to both HIV-2 single-infected (38 years IQR diagnosis was associated with inconsistent condom
28–44, p = 0.03) and HIV-1/2 dual-infected (46.5 years use with clients (AOR 3.0 (95% CI 1.04–8.9, p = 0.04)
IQR 35–49, p < 0.001) FSW but older than HIV-nega- (Table 2).
tive FSW (26 years IQR 22–32, p < 0.001). HIV-2 single- A history of HIV care was reported in 49.0% (95% CI
infected FSW had a higher median CD4 cell count (1039, 39.1–59.0, n = 51) of all HIV-1 infected FSW (Fig. 1),
IQR 727–1177) compared to both HIV-1 single-infected and in 83.6% (95% CI 71.9–91.8, n = 51) of the FSW
women (615 IQR 377–811 (p < 0.001)) and HIV-1/2 dual- previously diagnosed with an HIV-1 infection. Among
infected women (525 IQR 296–741 (p = 0.001)), while the HIV-2 single-infected FSW 28.6% (95% CI 8.4–58.1,
there was no significant difference between HIV-1 sin- n = 4) reported a history of HIV care, of whom all
gle-infected women and HIV-1/2 dual-infected women reported current ART use. Of all HIV-1 infected FSW,
(p = 0.38). 41.4% (95% CI 31.7–51.4, n = 43) reported taking ART
compared to 84.3% (95% CI 71.4–92.9, n = 43) of HIV-1
infected FSW with a history of HIV care and 70.5%
HIV and the care continuum
(95% CI 57.4–81.4, n = 43) of HIV-1 infected FSW with
The HIV Care continuum among all HIV-1 infected a previous diagnosis. Among the HIV-1 infected FSW
FSW including HIV-1/2 dual-infected women is pre- reporting current ART use, 55.8% (95% CI 39.9–70.9,
sented in Fig. 2 and in the following. Among the 104 n = 24) were virally suppressed, which was 23.1% (95%
HIV-1 infected FSW, 58.7% (95% CI 48.5–68.2, n = 61) CI 15.4–32.4, n = 24) of all women testing HIV-1 posi-
knew their HIV status. The median CD4 cell count and tive. An additional 6.7% (95% CI 2.7–13.4, n = 7) of
VL was 559 cells/mm3 (IQR 322.5–751) and 2707 cop- HIV-1 infected women were virally suppressed despite
ies/ml (IQR 20–15849), respectively. The correspond- not reporting ART use, which means that a total of
ing figures for HIV-1 infected FSW without a previous 29.8% of HIV-1 infected women (95% CI 21.2–39.6,
HIV diagnosis was 618 cells/mm3 (IQR 439–856) and n = 31) were virally suppressed. Self-reported adher-
8110 copies/ml (IQR 2677–57800), respectively. Among ence ≥ 90% measured by VAS, among 27 of the HIV-1
the 14 HIV-2 single-infected FSW 64.3% (95% CI 35.1– infected FSW reporting current ART use, was associ-
87.2, n = 9) knew their HIV status. Parameters associ- ated with viral suppression after age adjustments (odds
ated with undiagnosed HIV infection were determined ratio 20.0, 95% CI 2.5–161.7, p = 0.01).
by multivariable analysis. The analyses showed that
Lindman et al. AIDS Res Ther (2020) 17:33 Page 5 of 11

Table 1 Selected summary characteristics among HIV infected participants stratified by HIV type and HIV negative
participants
HIV-1 single-infected HIV-1/2 dual- HIV-2 single- HIV negative (n = 322) HIV-1
(n = 90) infected (n = 14) infected (n = 14) vs HIV
negative
p-value

Age 30 (25–37) 47 (35–49) 38 (28–44) 26 (22–32) < .001c

CD4 cell count cells/mm3 615 (377–811) 525 (296–741) 1039 (727–1177) NA NA
HIV-1 VL copies/ml 4417 (631–30,193) 3138 (20–21,600) NA NA NA
Region .002d
Bissau 45 (50.0%) 11 (78.6%) 3 (21.4%) 103 (32.0%)
Outside ­Bissaua 45 (50.0%) 3 (21.4%) 11 (78.6%) 219 (68.0%)
Education (years) .01e
None 33 (36.7%) 7 (50.0%) 8 (57.1%) 71 (22.1%)
1–5 19 (21.1%) 54 (28.9%) 1 (7.1%) 52 (16.2%)
6–9 22 (24.4%) 2 (14.3%) 2 (14.3%) 115 (35.7%)
9–12 7 (7.8%) 0 (0.0%) 3 (21.4%) 71 (22.1%)
Data missing 9 (10.0%) 1 (7.1%) 0 (0.0%) 13 (4.0%)
Marital status ≤ .001d
Single 30 (33.3%) 3 (21.4%) 5 (35.7%) 207 (64.3%)
Married 19 (21.1%) 2 (14.3%) 1(7.1%) 31 (9.6%)
Divorce or widowed 37 (41.1%) 9 (64.3%) 8 (57.1%) 77 (23.9%)
Data missing 4 (4.4%) 0 (0.0%) 0 (0.0%) 7 (2.2%)
Number of clients per week .08d
<9 43 (47.8%) 7 (50.0%) 11 (78.6%) 196 (60.9%)
≥ 10 33 (36.7%) 6 (42.9%) 2 (14.3%) 85 (26.4%)
Data missing 14 (15.5%) 1 (7.1%) 1 (7.1%) 41 (12.7%)
Condom ­useb .22d
Inconsistent 43 (47.8%) 6 (42.9%) 9 (64.3%) 136 (42.2%)
Consistent 42 (46.7%) 6 (42.9%) 4 (28.6%) 180 (55.9%)
Data missing 5 (5.6%) 2 (14.2%) 1 (7.1%) 6 (1.9%)
Data are n (%) or median (IQR)
IQR interquartile range, NA not applicable, VL viral load
a
Canchungo, Bafata, Gabu, Bambadinca, Buba, Quebo
b
Condom use last month; inconsistent including “Never” and “Sometimes”, consistent including “Always”
c
Mann–Whitney test U test
d
Chi Square test
e
Kruskal–Wallis test

HIV‑1 resistance mutations NNRTI only resistance mutations were detected in 18.2%
All resistance mutations identified in HIV-1 infected (95% CI 5.2–40.3, n = 4), NRTI only resistance mutations
FSW with a viral load ≥ 1000 copies/ml are summarized in 9.1% (95% CI 1.1–29.2, n = 2) and NNRTI + NRTI
in Table 3. Among HIV-1 infected FSW with a viral mutations were detected in 18.2% (95% CI 5.2–40.3,
load < 1000 copies/ml no HIVDR were detected in the n = 4). One individual had a protease inhibitor acces-
nine samples that were analyzed for HIVDR. At least one sory mutation. There was no difference in time on ART
HIVDR was detected in 9.4% (95% CI 3.1–20.7, n = 5) between FSW with or without HIVDR (3.6 IQR 1.7-4.4
of the 53 treatment naïve FSW, as compared with 50.0% and 3.2 years IQR 1.8–6.1, respectively, p = 0.59).
(95% CI 28.2–71.8, n = 11) of 22 ART experienced FSW. Table 4 shows all resistance mutations by subset in
Among the treatment naïve FSW, 6.0% (95% CI 1.2–15.7, the 16 FSW with a HIVDR. Overall, the most common
n = 3) had NNRTI mutations, and 4.0% (95% CI 0.5–13.0, NNRTI resistance mutation was K103N which was found
n = 2) had nucleoside reverse transcriptase inhibitor in 43.8% (95% CI 19.7–70.1, n = 7) of FSW with a HIVDR
(NRTI) mutations. Among the 22 ART experienced FSW, mutation. The most common NRTI mutation was
Lindman et al. AIDS Res Ther (2020) 17:33 Page 6 of 11

Fig. 2 HIV care continuum among all HIV-1 infected FSW (n = 104). The y-axis and the figures in the bars indicate the proportion of all women
testing HIV-1 positive. The proportion of women from each preceding step is described in the text

M184V which was found in 37.5% (95% CI 15.2–64.6, while the HIV-2 prevalence was nearly two times higher
n = 6) of FSW with a HIVDR mutation. By splitting the among the FSW observed in our study compared to
study period in two 18.5-month time strata; September adult women in the most recent community-based study
2014 to 15th March 2016 and ­16th March 2016 to Sep- from Bissau, were the HIV-1 and HIV-2 prevalence was
tember 2017, we investigated if any temporal trends in 5.2% and 3.4% respectively [35]. The CD4+ T cell lev-
prevalence of PDR among treatment naïve FSW could els were generally high, also among FSW not previously
be seen. The prevalence of PDR were 4.2% (95% CI 0.1– diagnosed, probably due to a relatively short duration of
21.1, n = 1) among 24 treatment naïve FSW included in infection among most participants.
the first time-period and 13.8% (95% CI 3.9–31.6, n = 4) Our finding that more than one-third of all HIV-1
among 29 treatment naïve FSW included in the last time- infected FSW and HIV-2 infected FSW were not aware of
period (p = 0.26 comparing the prevalence in the two their HIV infection is considerably higher than reported
time periods). in studies from Malawi, South Africa and Zimbabwe [13,
14, 37]. This is a concern because individuals that are
Discussion unaware of their HIV status will not be linked to HIV
In this study, we investigated the HIV care continuum care. Another concern is the increased risk of onward
and HIV-1 drug resistance among 440 FSW across six HIV transmission since FSW unaware of their HIV infec-
sites in Guinea-Bissau. The overall HIV prevalence was tion were more likely to have inconsistent condom use
26.8%, with nearly four times higher total HIV-1 preva- with clients. Currently, WHO recommends HIV testing
lence (23.6%) than total HIV-2 prevalence (6.4%) when every 12 months for FSW [38]. It is therefore plausible
including HIV-1/2 dual-infected FSW in each group. The that frequent testing strategies for FSW would be benefi-
comparably low HIV-2 prevalence is in concordance with cial in Guinea-Bissau, particularly among younger FSW
the decreasing HIV-2 prevalence that has been observed and FSW residing outside the capital Bissau.
in an occupational cohort of police officers, among preg- A meta-analysis and systematic review among FSW in
nant women and the general population. [34–36] The low-and-middle-income-countries found an estimated
prevalence of HIV-1 was more than four times higher ART coverage of 39.3% (27.2–52.9%) [11]. The ART
Lindman et al. AIDS Res Ther (2020) 17:33 Page 7 of 11

Table 2 Association between sociodemographic factors and transmission risk factors with a previously undiagnosed HIV
infection
n Undiagnosed HIV OR 95% CI p AORa 95% CI p
infection

HIV-type
HIV-1 90 40 (44.4%) Ref
HIV-2 14 5 (35.7%) 0.7 0.2–2.2 0.54
HIV-1/2 dual infected 14 3(21.4%) 0.3 0.1–1.3 0.12
Age
≥ 30 73 23 31.5%) Ref Ref
< 30 45 25 (55.6%) 2.7 1.3–5.9 0.01 2.7 1.2–6.5 0.02
Nationality
Guinea-Bissau 109 44 (40.4%) Ref
Otherb 9 4 (44.4%) 1.2 0.3–4.7 0.81
Region
Bissau 59 18 (30.5%) Ref Ref
Outside ­Bissauc 59 30 (50.9%) 2.4 1.1–5.1 0.03 2.4 1.0-5.8 0.05
Marital status
Single 38 15 (39.5%) Ref
Married 22 8 (36.4%) 0.9 0.3–2.6 0.81
Divorced/widowed 54 22 (40.7%) 1.1 0.5–2.5 0.90
Data missing 4 3 (75.0%)
Children
≥ 1 child 98 36 (36.7%) Ref
None 16 10 (62.5%) 2.9 1.0–8.6 0.06
Data missing 4 2 (50.0%)
Education (years)
None 48 18 (37.5%) Ref Ref
1–5 24 9 (37.5%) 1 0.4–2.8 1.0 Ref
6–9 26 9 (34.6%) 0.9 0.3–2.4 0.81 Ref
10–12 10 7 (70.0%) 3.9 0.9–16.7 0.07 4.2 0.9–19.9 0.08
Data missing 10 5 (50.0%)
Another source of ­incomed
No 61 22 (36.1%) Ref
Yes 53 25 (47.2%) 1.6 0.7–3.4 0.23
Data missing 4 1 (25.0%)
Number of c­ lientse
≥2 40 14 35.0%) Ref
0–2 62 30 (48.4%) 1.7 0.8–3.9 0.18
Data missing 16 4 (25.0%)
Condom use with ­clientf
Consistent 85 31 (36.5%) Ref Ref
Inconsistent 23 37 (60.9%) 2.7 1.1–7.0 0.04 3.0 1.04–8.4 0.04
Data missing 10 3 (30.0%)
Alcohol ­comsumptiong
Never 74 35 (47.3%) Ref
Yes 40 12 (30.0%) 0.5 0.2–1.1 0.08
Data missing 4 1(25.0%)
AOR adjusted odds ratio, CI confidence interval, OR odds ratio, p p-value, Ref reference category
a
In the final multivariate model the following variables were included; age, region, education (0–9 years vs 10–12 years), and condom use
b
Including Gambia and Senegal
c
Including Canchungo, Bafata, Gabu, Bambadinca, Buba, Quebo
d
Besides sex work
Lindman et al. AIDS Res Ther (2020) 17:33 Page 8 of 11

Table 2 (continued)
e
Number of clients last day of sex work
f
Do you accept condomless sex with clients?; inconsistent including “Yes”, Consistent including “No”
g
Alcohol consumption last month; Yes including “Every day”, “Once a week”, “less than once a week”, No including “Never”

Table 3 Summary characteristics by treatment status among HIV-1 infected participants with viral load ≥ 1000 copies/ml
Treatment ­naivea (n = 53) ART ­expereriencedb (n = 22) Treatment
Naive vs ART
experienced
p-value

Age 30 (24–35) 42 (30–46) .002c

HIV-1/2 dual-infected 4 (7.6%) 5 (22.7%) 0.07d
CD4 cells/mm3 584 (373–787) 432 (184–726) .17c
HIV-1 VL copies/ml 25,461 (5649–59,182) 7130 (2707–21,771) .01c
Previous diagnosis 14 (27.5%) 22 (100.0%) NA
Non-mutated virus 48 (90.6%) 11 (50.0%)
Detectable resistance 5 (9.4%) 11 (50.0%) < .001d
NNRTI only 3 (5.7%) 4 (18.2%) NA
NRTI only 2 (3.8%) 2 (9.1%) NA
NRTI + NNRTI 0 (0.0%) 4 (18.1%) NA
PI minor 0 (0.0%) 1 (4.6%) NA
Data are n (%) or median (IQR)
ART​ antiretroviral therapy, NNRTI non-nucleoside reverse transcriptase inhibitors, NRTI nucleoside reverse transcriptase inhibitor, NA not applicable, PI protease
inhibitors, VL viral load
a
Including 3 seroincident individuals
b
Including 3 individuals with previous ART use
c
Mann–Whitney test U test
d
Chi Square test

coverage among all HIV-1 infected FSW in our study non-adherence, but given our findings regarding PDR,
was 41.4%, which is comparable to this meta-analysis as it is possible that some of these mutations represents
well as other studies of FSW from Zimbabwe (43.4%) and transmitted drug resistance. In nearly half of the FSW
South Africa (43.9%), but lower than in Malawi (52.2%) on treatment with viremia, non-mutated virus was
[13, 14, 37]. The corresponding ART coverage for HIV-2 identified which suggest treatment interruptions as the
single-infected women in our study was 28.6%. We cause of their virological failure. Other explanations
recently showed that HIV-2 is more pathogenic than pre- could be problems with drug dosing or absorption, as
viously thought and that the majority of HIV-2 infected previously described by Lessells et al. [41].
individuals will progress to HIV-related disease and Total HIVDR in our study (as percentage of all HIV-1
death without treatment, further emphasizing the impor- infected participants) was in line with a recent study
tance of high ART coverage among HIV-2 infected indi- from South Africa (15.4% vs 16.7%) [37]. Similarly to
viduals [39]. our study, the report from South Africa included both
The status of the UNAIDS goals among the general FSW on treatment, FSW reporting treatment discon-
population of women of the same age in Guinea-Bissau tinuation, and treatment naïve FSW. The most com-
have not been detailed. However, the ART coverage mon resistance mutation in the ART naïve FSW was
among FSW in our study did not reach the 90-90-90 the K103N and K103S mutations, which is similar to
goals set by UNAIDS but among FSW on ART 55.8% a recent study of pregnant women in Guinea Bissau
were virally suppressed, indicating that the majority [25]. The prevalence of PDR was high, especially in the
of FSW are likely to be adherent to their ART regime second part of the study were the prevalence reached
[40]. Moreover, more than half of the FSW on treat- 13.8% although with a large uncertainty of the estimate.
ment that failed to suppress their virus had at least one This is worrisome and further studies are necessary
HIVDR mutation. It is likely that many of these muta- to investigate if PDR is increasing in Guinea-Bissau.
tions represent acquired resistance mutations due to Moreover, the most frequent mutations found in our
Lindman et al. AIDS Res Ther (2020) 17:33 Page 9 of 11

Table 4 HIVDR mutations by treatment status among 16 in other studies of FSW [13, 14]. The most likely expla-
FSW with detectable HIVDR in Guinea-Bissau nation is misclassification, but it could also be possi-
Drug class HIVDR Treatment ART Total (n = 16) ble that a small proportion of these women were elite
Mutation Naive ­experienceda controllers [21, 43]. Regarding HIVDR data, the sample
(n = 16) (n = 5) (n = 11) was small and therefore limited the generalizability.
NNRTI K103N/S 3 (60.0%) 4 (36.4%) 7 (43.8%)b Moreover, it cannot be excluded that women report-
A98G 0 (0.0%) 2 (18.2%) 2 (12.5%) ing not being on ART could have previously received
E1238A 0 (0.0%). 1 (9.1%) 1 (6.3%) PMTCT, even though fieldworkers probed for this.
K238N 0 (0.0%) 1 (9.1%) 1 (6.35)
K238T 0 (0.0%) 1 (9.1%) 1 (6.3%)
P225H 0 (0.0%) 1 (9.1%) 1 (6.3%) Conclusion
V106A 0 (0.0%) 1 (9.1%) 1 (6.3%) This is the first study to characterize the HIV care con-
V179E 0 (0.0%) 1 (9.1%) 1 (6.3%) tinuum among FSW in Guinea-Bissau. Our study sug-
Y188H 0 (0.0%) 1 (9.1%) 1 (6.3%) gests that FSW are highly burdened to HIV compared
Y188L 1 (20.0%) 0 (0.0%) 1 (6.3%) to adult women in Guinea-Bissau, and of all HIV-1
NRTI M184V 0 (0.0%) 6 (54.5%) 6 (37.5%)b infected women only a third were virally suppressed.
M41L 1 (20.0%) 1 (9.1%) 2 (12.5%)
We also found high levels of HIVDR mutations among
T215Y 0 (0.0%) 2 (18.2%) 2 (12.5%)
both treatment naïve FSW and FSW on ART. Future
D67N 1 (20.0%) 0 (0.0%) 1 (6.3%)
studies are needed to assess HIV prevalence and
E44D 0 (0.0%) 1 (10.0%) 1 (6.3%)
HIVDR mutations among FSW and other most-at-risk-
K219E 1 (20.0%) 0 (0.0%) 1 (6.3%)
populations (MARPs) in the region. Such studies would
T215FY 0 (0.0%) 1 (9.1%) 1 (6.3%)
be pivotal to inform future targeted interv against
T215I 1 (20.0%) 0 (0.0%) 1 (6.3%)
MARPs in resource-limited settings like Guinea-Bissau.
PI L89V 0 (0.0%) 1 (9.1%) 1 (6.3%)b
Data are n (%) Abbreviations
ART​ antiretroviral therapy, HIVDR HIV-1 drug resistance, NNRTI non-nucleoside
FSW: Female sex workers; HIVDR: HIV drug resistance; ART​: Antiretroviral
reverse transcriptase inhibitors, NRTI nucleoside reverse transcriptase inhibitor, therapy; PDR: Pre-treatment drug resistance; NNRTI: Non-nucleoside reverse
PI protease inhibitors transcriptase inhibitors; LNSP: The National Public Health Laboratory; ENDA:
a Environmental action in the third world; VAS: Visual analog scale; VL: Viral load;
Including 10 study participants with current ART use and 1 study participant
qPCR: Quantitative PCR; PCR: Polymerase chain reaction; DRM: Drug resistance
with previous ART use
mutations; AOR: Adjusted odds ratio; NRTI: Nucleoside reverse transcriptase
b
The most common HIVDR in each drug class highlighted in italics inhibitor; MARPs: Most-at-risk-populations.

Acknowledgements
study has also been reported to be common among The authors would first and foremost like to thank all participants in the study.
The listed authors and the members of the Sweden Guinea-Bissau Cohort
patients failing first line ART in the country [42]. Research (SWEGUB CORE) group, including Babetida N’Buna, Antonio Biague,
Female sex workers are a highly mobile and vulner- Ansu Biai, Cidia Camara, Zacarias Jose da Silva, Joakim Esbjörnsson, Marianne
able population in Guinea-Bissau. We therefore used Jansson, Sara Karlson, Jacob Lindman, Patrik Medstrand, Fredrik Månsson,
Hans Norrgren, Gülsen Özkaya Sahin, and Sten Wilhelmson, also wish to thank
a mixed venue-based and chain-referral convenience the staff of the National Public Health Laboratory and ENDA in Bissau, Guinea-
sampling. Hence, it is possible that our study popula- Bissau for their assistance during data collection and sampling handling of
tion is not representative of all FSW in Guinea-Bis- this study.
sau. In addition, we could not adjust for clustering by Authors’ contributions
recruitment chain or venue, other than city, because JL, PM, JE and HN designed the study, oversaw implementation, conducted
data on which participants were recruited by whom statistical analyses, provided interpretation of study findings and drafted
the article. MAD and AB contributed to study design, provided guidance for
or from where were not recorded. It is possible that study conduction and undertook data collection. FM and MJ contributed to
Respondent Driven Sampling could have addressed study design, provided guidance for study conduction and contributed to
these difficulties, but due to budget and resource limita- interpretation of findings. All authors critically revised the article and approved
submission.
tions, we decided to use the more cost-effective mixed
venue-based and chain-referral convenience sampling. Funding
Information on HIV care continuum outcomes mainly Open access funding provided by Lund University. The study was supported
by the Swedish Research council (2013-06541), Lund University (Dnr F:
relied on self-report, and thus subject to social desira- 2014/354) and Region Skåne Research and Development (REGSKANE-826071).
bility and misclassification. Of the HIV positive women
reporting not being on ART, 6.7% had a VL < 1000 cop- Availability of data and materials
The dataset used for the current study is available from the corresponding
ies/ml. Discrepancies between viral suppression and author on reasonable request
self-reporting of not being on ART has been shown also
Lindman et al. AIDS Res Ther (2020) 17:33 Page 10 of 11

Ethics approval and consent to participate programme for prevention of HIV, an integrated response (SAPPH-IRe)
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