Evaluation of the rubella surveillance system in South Africa, 2016-2018: A cross-sectional study

BACKGROUND

Rubella is a leading vaccine-preventable cause of birth defects. We conducted this study to evaluate the rubella surveillance system in South Africa from 2016 to 2018. The rubella surveillance system had not been evaluated since its inception; therefore, a formal evaluation is necessary to assess key attributes and to ascertain the extent to which the system achieves its objectives.

METHODS

We conducted a cross-sectional study to assess the usefulness, simplicity, positive predictive value, timeliness, and data quality of the rubella surveillance system from 2016 to 2018. We reviewed retrospective rubella surveillance data and conducted a survey with key stakeholders of the system. We compiled a summary report from the survey and calculated the annualized detection rate of rubella and non-rubella febrile rash, positive predictive value, the proportion of complete records, and timeliness between the surveillance steps. We compared our results with recommended performance indicators from the 2015 revised World Health Organization African regional guidelines for measles and rubella surveillance.

RESULTS

The rubella surveillance system was useful but weak in terms of simplicity. The annualized detection rate of rubella febrile rash was 1.5 per 100,000 populations in 2016, 4.4 in 2017, and 2.1 in 2018. The positive predictive value was 29.1% in 2016, 40.9% in 2017, and 32.9% in 2018. The system did not meet the timeliness goal in the health facility component but met this goal in the laboratory component. The system had poor data quality, particularly in the health facility component.

CONCLUSIONS

The rubella surveillance system was useful, although it was not simple to use and had low PPV, poor timeliness, and poor data quality. Efforts should be made to improve the system's simplicity, PPV, timeliness, and data quality at the facility level.

Factors Associated with Syphilis Transmission and Acquisition Among Men Who Have Sex with Men (MSM): Protocol for a Multi-Site Egocentric Network Study (Preprint)

BACKGROUND

In the United States, the rates of primary and secondary syphilis have increased more rapidly among men who have sex with men (MSM) than among any other subpopulation. Rising syphilis rates among MSM reflect changes in both individual behaviors and the role of sexual networks (eg, persons linked directly or indirectly by sexual contact) in the spread of the infection. Decades of research examined how sexual networks influence sexually transmitted infections (STIs) among MSM; however, few longitudinal data sources focusing on syphilis have collected network characteristics. The Centers for Disease Control and Prevention, in collaboration with 3 sites, enrolled a prospective cohort of MSM in 3 US cities to longitudinally study sexual behaviors and STIs, including HIV, for up to 24 months.

OBJECTIVE

The Network Epidemiology of Syphilis Transmission (NEST) study aimed to collect data on the factors related to syphilis transmission and acquisition among MSM.

METHODS

The NEST study was a prospective cohort study that enrolled 748 MSM in Baltimore, Maryland; Chicago, Illinois; and Columbus, Ohio. NEST recruitment used a combination of convenience sampling, venue-based recruitment, and respondent-driven sampling approaches. At quarterly visits, participants completed a behavioral questionnaire and were tested for syphilis, HIV, gonorrhea, and chlamydia. The participants also provided a list of their sexual partners and described their 3 most recent partners in greater detail.

RESULTS

The NEST participants were enrolled in the study from July 2018 to December 2021. At baseline, the mean age of the participants was 31.5 (SD 9.1) years. More than half (396/727. 54.5%) of the participants were non-Hispanic Black, 29.8% (217/727) were non-Hispanic White, and 8.8% (64/727) were Hispanic or Latino. Multiple recruitment strategies across the 3 study locations, including respondent-driven sampling, clinic referrals, flyers, and social media advertisements, strengthened NEST participation. Upon the completion of follow-up visits in March 2022, the mean number of visits per participant was 5.1 (SD 3.2; range 1-9) in Baltimore, 2.2 (SD 1.6; range 1-8) in Chicago, and 7.2 (SD 2.9; range 1-9) in Columbus. Using a community-based participatory research approach, site-specific staff were able to draw upon collaborations with local communities to address stigma concerning STIs, particularly syphilis, among potential NEST participants. Community-led efforts also provided a forum for staff to describe the NEST study objectives and plans for research dissemination to the target audience. Strategies to bolster data collection during the COVID-19 pandemic included telehealth visits (all sites) and adaptation to self-collection of STI specimens (Baltimore only).

CONCLUSIONS

Data from NEST will be used to address important questions regarding individual and partnership-based sexual risk behaviors among MSM, with the goal of informing interventions to prevent syphilis in high-burden areas.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/40095.

Trends in the prevalence of microscopically-confirmed schistosomiasis in the South African public health sector, 2011-2018

Background

Schistosomiasis, also known as bilharzia, is a chronic parasitic blood fluke infection acquired through contact with contaminated surface water. The illness may be mild or can cause significant morbidity with potentially serious complications. Children and those living in rural areas with limited access to piped water and services for healthcare are the most commonly infected. To address the prevalence of the disease in parts of South Africa (SA) effective national control measures are planned, but have not yet been implemented. This study aimed to estimate the prevalence and trends of public sector laboratory-confirmed schistosomiasis cases in SA over an eight-year (2011–2018) period, to inform future control measures.

Methodology & principal findings

This is a descriptive analysis of secondary data from the National Health Laboratory Service (NHLS). The study included all records of patients for whom microscopic examination detected Schistosoma species eggs in urine or stool specimens from January 2011 to December 2018. Crude estimates of the prevalence were calculated using national census mid-year provincial population estimates as denominators, and simple linear regression was used to analyse prevalence trends. A test rate ratio was developed to describe variations in testing volumes among different groups and to adjust prevalence estimates for testing variations.

A total number of 135 627 schistosomiasis cases was analysed with the highest prevalence observed among males and individuals aged 5–19 years. We describe ongoing endemicity in the Eastern Cape Province, and indicate important differences in the testing between population groups.

Conclusion

While there was no overall change in the prevalence of schistosomiasis during the analysis period, an average of 36 people per 100 000 was infected annually. As such, this represents an opportunity to control the disease and improve quality of life of affected people. Laboratory-based surveillance is a useful method for reporting occurrence and evaluating future intervention programs where resources to implement active surveillance are limited.

This is the first paper to describe the prevalence of human schistosomiasis in South Africa using nationally representative data. The prevalence remained consistent during the eight-year period, independent of increasing annual testing volumes. Groups with the highest burden included males and individuals aged 5–19 years. The schistosomiasis-endemic provinces of Limpopo, Mpumalanga and KwaZulu-Natal emerged as the highest-burdened areas, and ongoing endemicity in Eastern Cape Province was demonstrated. Western Cape Province likely reported cases imported from endemic provinces rather than being acquired by local transmission. In summary, schistosomiasis remains an important public health problem in South Africa that needs long-term sustainable, effective standardised interventions to reduce the burden. Passive laboratory-based surveillance is a practical tool for reporting prevalence, and could be used to monitor and evaluate future intervention programs.