Circulation and seasonality of influenza viruses in different transmission zones in Africa.

BACKGROUND: Influenza is responsible for more than 5 million severe cases and 290,000 to 650,000 deaths every year worldwide. Developing countries account for 99% of influenza deaths in children under 5 years of age. This paper aimed to determine the dynamics of influenza viruses in African transmission areas to identify regional seasonality for appropriate decision-making and the development of regional preparedness and response strategies. METHODS: We used data from the WHO FluMart website collected by National Influenza Centers for seven transmission periods (2013-2019). We calculated weekly proportions of positive influenza cases and determined transmission trends in African countries to determine the seasonality. RESULTS: From 2013 to 2019, influenza A(H1N1)pdm2009, A(H3N2), and A(H5N1) viruses, as well as influenza B Victoria and Yamagata lineages, circulated in African regions. Influenza A(H1N1)pdm2009 and A(H3N2) highly circulated in northern and southern Africa regions. Influenza activity followed annual and regional variations. In the tropical zone, from eastern to western via the middle regions, influenza activities were marked by the predominance of influenza A subtypes despite the circulation of B lineages. One season was identified for both the southern and northern regions of Africa. In the eastern zone, four influenza seasons were differentiated, and three were differentiated in the western zone. CONCLUSION: Circulation dynamics determined five intense influenza activity zones in Africa. In the tropics, influenza virus circulation waves move from the east to the west, while alternative seasons have been identified in northern and southern temperate zones. Health authorities from countries with the same transmission zone, even in the absence of local data based on an established surveillance system, should implement concerted preparedness and control activities, such as vaccination.

What drives mortality among HIV patients in a conflict setting? A prospective cohort study in the Central African Republic.

BACKGROUND: Provision of antiretroviral therapy (ART) during conflict settings is rarely attempted and little is known about the expected patterns of mortality. The Central African Republic (CAR) continues to have a low coverage of ART despite an estimated 110,000 people living with HIV and 5000 AIDS-related deaths in 2018. We present results from a cohort in Zemio, Haut-Mboumou prefecture. This region had the highest prevalence of HIV nationally (14.8% in a 2010 survey), and was subject to repeated attacks by armed groups on civilians during the observed period. METHODS: Conflict from armed groups can impact cohort mortality rates i) directly if HIV patients are victims of armed conflict, or ii) indirectly if population displacement or fear of movement reduces access to ART. Using monthly counts of civilian deaths, injuries and abductions, we estimated the impact of the conflict on patient mortality. We also determined patient-level risk factors for mortality and how the risk of mortality varies with time spent in the cohort. Model-fitting was performed in a Bayesian framework, using logistic regression with terms accounting for temporal autocorrelation. RESULTS: Patients were recruited and observed in the HIV treatment program from October 2011 to May 2017. Overall 1631 patients were enrolled and 1628 were included in the analysis giving 48,430 person-months at risk and 145 deaths. The crude mortality rate after 12 months was 0.92 (95% CI 0.90, 0.93). Our model showed that patient mortality did not increase during periods of heightened conflict; the odds ratios (OR) 95% credible interval (CrI) for i) civilian fatalities and injuries, and ii) civilian abductions on patient mortality both spanned unity. The risk of mortality for individual patients was highest in the second month after entering the cohort, and declined seven-fold over the first 12 months. Male sex was associated with a higher mortality (odds ratio 1.70 [95% CrI 1.20, 2.33]) along with the severity of opportunistic infections (OIs) at baseline (OR 2.52; 95% CrI 2.01, 3.23 for stage 2 OIs compared with stage 1). CONCLUSIONS: Our results show that chronic conflict did not appear to adversely affect rates of mortality in this cohort, and that mortality was driven predominantly by patient-specific risk factors. The risk of mortality and recovery of CD4 T-cell counts observed in this conflict setting are comparable to those in stable resource poor settings, suggesting that conflict should not be a barrier in access to ART.

Spectrum of female commercial sex work in Bangui, Central African Republic.

Classification of professional and non-professional female sex workers (FSWs) into different categories, never previously reported in the Central African Republic (CAR), may be useful to assess the dynamics of the human immunodeficiency virus (HIV) epidemic, design operational intervention programmes to combat HIV and other sexually transmitted infections (STIs) and to adapt these programmes to the broad spectrum of sexual transactions in the CAR. Our study proposes a socio-behavioural classification of FSWs living in the CAR and engaged in transactional and commercial sex. Thus, the aims of the study were these: (i) to categorize FSWs according to socio-anthropologic criteria in Bangui and (ii) to examine the association between a selection of demographic and risk variables with the different categories of female sex work as an outcome. A cross-sectional questionnaire survey was conducted in 2013 to describe the spectrum of commercial sex work (CSW) in Bangui among 345 sexually active women having more than 2 sexual partners, other than their regular partner, during the prior 3 months and reporting to have received money or gifts in return for their sexual relationships. According to socio-behavioural characteristics, FSWs were classified into six different categories. Professional FSWs, constituting 32.5% of the interviewed women, were divided in two categories: pupulenge (13.9%), i.e., dragonflies (sometimes called gba moundjou, meaning literally look at the White) consisting of roamers, who travel around the city to hotels and nightclubs seeking wealthy clients, with a preference for French men; and the category of kata (18.6%), i.e., FSWs working in poor neighbourhoods. Non-professional FSWs, constituting 67.5% of the interviewed women, were divided into four categories: street and market vendors (20.8%), students (19.1%), housewives (15.7%) and unskilled civil servants (11.9%). In general, CSW in the CAR presents a remarkably heterogeneous phenomenon. Risk-taking behaviour regarding STI/HIV infection appears to be different according to the different categories of female CSW. The groups of katas and street vendors were poorer and less educated, consumed more alcohol or other psycho-active substances (cannabis, tramadol and glue) and, consequently, were more exposed to STI. Our results emphasise the high level of vulnerability of both poor professional FSWs (kata) and non-professional sex workers, especially street vendors, who should be taken into account when designing prevention programmes targeting this population for STI/HIV control purposes.

Risk factors for HIV infection among female sex workers in Bangui, Central African Republic.

OBJECTIVE: The aims of the study were i) to categorize female sex workers (FSW) according to socio-anthropologic criteria in Bangui; ii) to examine the association between a selection of demographic and risk variables with the different categories of female sex work as outcome, and iii) to investigate factors associated with HIV status. METHODS: A cross-sectional questionnaire survey was conducted to describe the spectrum of commercial sex work in Bangui among 345 sexually active women. After collection of social and behavioral characteristics, each woman received a physical examination and a blood sample was taken for biological analyses, including HIV testing. The relationships between sociodemographic characteristics, behavioral variables involved in high risk for HIV as well as biological results were investigated by bivariate analysis in relationship with FSW categories as main outcomes, and by bivariate analysis followed by multivariate logistic regression analysis in relationship with HIV as the main outcome. The strength of statistical associations was measured by crude and adjusted Odds ratios (OR) and their 95% confidence intervals. RESULTS: The typology of FSW comprised six different categories. Two groups were the "official" professional FSW primarily classified according to their locations of work [i) "kata"(18.55%) representing women working in poor neighborhoods of Bangui; ii) "pupulenge" (13.91%) working in hotels and night clubs to seek white men]. Four groups were "clandestine" nonprofessional FSW classified according to their reported main activity [i) "market and street vendors" (20.86%); ii) "schoolgirls or students" (19.13%) involved in occasional transactional sex (during holidays); iii) "housewives or unemployed women" (15.65%); iv) "civil servants" (11.88%) working as soldiers or in the public sector]. The overall prevalence of HIV-1 was 19.12% (66/345). HIV varied according to FSW categories. Thus, among professional FSW, the HIV prevalence was 6-fold higher in "kata" than "pupulenge" (39.13% versus 6.30%; P = 0.001). Among nonprofessional FSW, the "vendors" showed the highest HIV prevalence (31.91%), which was higher than in "students" (6.10%; P = 0.001), "civil servants" (9.83%; P = 0.005), and "housewives" (13.00%; P = 0.01). In bivariate analysis, the following variables showed statistically significant association with risk for HIV infection: nationality; age of first sexual intercourse; self-assessment of HIV risk; knowledge of HIV status; anal sex practice with last clients; irregular condom use in last week; consumption of alcohol; other psycho-active substances; past history of STIs; HBs Ag; HSV-2 and bacterial vaginosis. However, the variable "sex workers categories" dichotomized into professional versus nonprofessional FSW was no longer associated with HIV. In multivariate logistical regression analysis, HIV infection was strongly associated with nationality (15.65% versus 3.77%) [adjusted OR (aOR) 3.39: 95% CI:1.25-9.16, P<0.05]; age of first sexual intercourse (21.10% versus 14.00%) (aOR 2.13: 95% CI: 1.03-4.39, P<0.05); anal sex practice with last clients (43.40% versus 11.50%) (aOR 4.31: 95% CI:2.28-8.33, P<0.001); irregular condom use in past week (33.50% versus 3.00%) (aOR 5.49: 95% CI:1.89-15.98, P<0.001); alcohol consumption before sex (34.70% versus 7.80%) (aOR 2.69: 95% CI:1.22-4.96, P<0.05); past history of STIs (41.00% versus 10.80%) (aOR 2.46: 95% CI:1.22-4.97, P<0.05) and bacterial vaginosis (29.80% versus 4.29%) (aOR 6.36: 95% CI: 2.30-17.72, P<0.001). CONCLUSION: Our observations highlight the high level of vulnerability for HIV acquisition of both poor professional "kata" and nonprofessional "street vendor" FSW categories. These categories should be particularly taken into account when designing specific prevention programs for STIs/HIV control purposes.