Background In 2007 the World Health Organization (WHO) launched the global initiative to eliminate mother-to-child transmission of syphilis (congenital syphilis, or CS). To assess progress towards the goal of <50 CS cases per 100,000 live births, we generated regional and global estimates of maternal and congenital syphilis for 2016 and updated the 2012 estimates. Methods Maternal syphilis estimates were generated using the Spectrum-STI model, fitted to sentinel surveys and routine testing of pregnant women during antenatal care (ANC) and other representative population data. Global and regional estimates of CS used the same approach as previous WHO estimates. Results The estimated global maternal syphilis prevalence in 2016 was 0.69% (95% confidence interval: 0.57–0.81%) resulting in a global CS rate of 473 (385–561) per 100,000 live births and 661,000 (538,000–784,000) total CS cases, including 355,000 (290,000–419,000) adverse birth outcomes (ABO) and 306,000 (249,000–363,000) non-clinical CS cases (infants without clinical signs born to un-treated mothers). The ABOs included 143,000 early fetal deaths and stillbirths, 61,000 neonatal deaths, 41,000 preterm or low-birth weight births, and 109,000 infants with clinical CS. Of these ABOs– 203,000 (57%) occurred in pregnant women attending ANC but not screened for syphilis; 74,000 (21%) in mothers not enrolled in ANC, 55,000 (16%) in mothers screened but not treated, and 23,000 (6%) in mothers enrolled, screened and treated. The revised 2012 estimates were 0.70% (95% CI: 0.63–0.77%) maternal prevalence, and 748,000 CS cases (539 per 100,000 live births) including 397,000 (361,000–432,000) ABOs. The estimated decrease in CS case rates between 2012 and 2016 reflected increased access to ANC and to syphilis screening and treatment. Conclusions Congenital syphilis decreased worldwide between 2012 and 2016, although maternal prevalence was stable. Achieving global CS elimination, however, will require improving access to early syphilis screening and treatment in ANC, clinically monitoring all women diagnosed with syphilis and their infants, improving partner management, and reducing syphilis prevalence in the general population by expanding testing, treatment and partner referral beyond ANC.

BackgroundIt is commonly assumed that sexual risk factors for heterosexual HIV transmission in sub-Saharan Africa, such as multi-partner sex, paid sex and co-infections, become less important as HIV epidemics mature and prevalence increases.Methods and FindingsWe conducted a systematic review of 68 African epidemiological studies from 1986 to 2006 involving 17,000 HIV positive adults and 73,000 controls. We used random-effects methods and stratified results by gender, time, background HIV prevalence rates and other variables. The number of sex partners, history of paid sex, and infection with herpes simplex virus (HSV-2) or other sexually-transmitted infections (STIs) each showed significant associations with HIV infection. Among the general population, the odds ratio (OR) of HIV infection for women reporting 3+ sex partners versus 0–2 was 3.64 (95%CI [2.87–4.62]), with similar risks for men. About 9% of infected women reported ever having been paid for sex, versus 4% of control women (OR = 2.29, [1.45–3.62]). About 31% of infected men reported ever paying for sex versus 18% of uninfected men (OR = 1.75, [1.30–2.36]). HSV-2 infection carried the largest risk of HIV infection: OR = 4.62, [2.85–7.47] in women, and OR = 6.97, [4.68–10.38] in men. These risks changed little over time and stratification by lower and higher HIV background prevalence showed that risk ratios for most variables were larger in high prevalence settings. Among uninfected controls, the male-female differences in the number of sex partners and in paid sex were more extreme in the higher HIV prevalence settings than in the lower prevalence settings.SignificanceMulti-partner sex, paid sex, STIs and HSV-2 infection are as important to HIV transmission in advanced as in early HIV epidemics. Even in high prevalence settings, prevention among people with high rates of partner change, such as female sex workers and their male clients, is likely to reduce transmission overall.

SummaryDengue is highly endemic in southern Vietnam and all four serotypes of dengue virus have already been identified. To determine the age-specific prevalence of dengue and associated risk factors, we conducted a serological study at two primary schools and assessed risk factors by analysing children's questionnaires and household surveys. Sera were collected from 961 primary schoolchildren in Binh Thuan Province and tested for the presence of dengue virus serum antibodies using an indirect immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). The antibody prevalence of the total population was 65.7% (n ¼ 631) which increased from 53.0 to 88.2% with age. The annual incidence of a first dengue infection, estimated by binary regression of the seroprevalence by age, was 11.7%. Interestingly, the prevalence of dengue IgG antibodies was significantly higher in children who confirmed using a pit latrine (RR 1.467, 95% CI: 1.245-1.730) and whose domestic environment contained discarded cans (RR 1.238, 95% CI: 1.042-1.470) and pigs (RR 1.228, 95% CI: 1.002-1.504). The epidemiology of dengue in southern Vietnam is stable with a constantly high annual incidence of first infections. Transmission occurs mainly peri-domestically, which has important public health implications.

Several clinical trials have demonstrated that antiretroviral (ARV) drugs, taken as pre-exposure prophylaxis (PrEP), can prevent HIV infection1, with the magnitude of protection ranging from -49 to 86%2–11. While these divergent outcomes are thought to be due primarily to product adherence12, biological factors likely contribute13. Despite selective recruitment of higher risk participants for prevention trials, HIV risk is heterogeneous, even within higher risk groups14–16. To determine whether this heterogeneity could influence PrEP outcomes, we undertook a post-hoc prospective analysis of the CAPRISA 004 tenofovir 1% gel trial (n=774), one of the first trials to demonstrate protection against HIV infection. Concentrations of nine pro-inflammatory cytokines were measured in cervicovaginal lavages at >2,000 visits, and a graduated cytokine score was used to define genital inflammation. In women without genital inflammation, tenofovir was 57% protective against HIV (95% CI: 7 to 80%), compared to 3% (95% CI: −104 to 54%) if genital inflammation was present. Among high gel adherers, tenofovir protection was 75% (95% CI: 25 to 92%) in women without inflammation compared to −10% (95% CI: −184 to 57%) in women with inflammation. Host immune predictors of HIV risk may modify the effectiveness of HIV prevention tools; reducing genital inflammation in women may augment HIV prevention efforts.

Objectives Assessments of population-level effects of antiretroviral therapy (ART) programs in Africa are rare. We use data from burial sites to estimate trends in adult AIDS mortality and the mitigating effects of ART in Addis Ababa. ART has been available since 2003, and for free since 2005. Methods To substitute for deficient vital registration, we use surveillance of burials at all cemeteries. We present trends in all-cause mortality, and estimate AIDS mortality (ages 20–64) from lay reports of causes of death. These lay reports are first used as a diagnostic test for the true cause of death. As reference standard we use the cause of death established via verbal autopsy interviews conducted in 2004. The Positive Predictive Value and Sensitivity are subsequently used as anchors to estimate the number of AIDS deaths for the period 2001–2007. Estimates are compared with Spectrum projections. Results Between 2001 and 2005, the number of AIDS deaths declined by 21.9% and 9.3% for men and women, respectively. Between 2005 and 2007, the number of AIDS deaths declined by 38.2% for men and 42.9% for women. Compared to the expected number in the absence of ART, the reduction in AIDS deaths in 2007 is estimated between 56.8% and 63.3%, depending on the coverage of the burial surveillance. Conclusion Five years into the ART program, adult AIDS mortality has been reduced by more than half. Following the free provision of ART in 2005, the decline accelerated and became more gender balanced. Substantial AIDS mortality, however, persists.