Results from two bio-behavioral surveillance surveys among older men who have sex with men in Eswatini

BACKGROUND: Surveillance data suggest new HIV infections are declining across much of sub-Saharan Africa, including Eswatini. However, in generalized HIV epidemics, there are limited data on HIV incidence among key populations (KPs). The World Health Organization recommends bio-behavioral surveillance surveys (BBSS) as integral components of national HIV strategies and surveillance systems. Some KPs such as older men who have sex with men (MSM) are difficult to reach through these surveys and, thus, less is known about their infection rates than other, more accessible MSM. We compared data from two BBSS in Eswatini to measure participation and HIV prevalence over time among older MSM.
METHODS: We conducted two national BBSS in four regions (July'"­"­December 2011 and October 2020'January 2021). The first BBSS surveyed 319 MSM at one study site, while the second surveyed 450 MSM at five study sites. Both used respondent-driven sampling and identical inclusion criteria for MSM: age 18 or older and anal sex with a male partner in the past 12 months.
RESULTS: The HIV case-finding rate among all MSM rose from 17% in the 2011 BBSS to 24% in the 2020'2021 BBSS and remained disproportionately high among older MSM (41% and 43%, respectively). In 2011, older MSM accounted for 7% of those tested and 17% of those found HIV positive, vs. 31% and 57%, respectively, in 2020'2021 (Table 1).

	Indicator	30+ Years	<30 Years	Total
2011 BBSS	Tested	22	297	319
	Distribution tested	7%	93%	100%
	HIV positive Distribution	17% (n=9)	83% (n=45)	100% (n=54)
	Case-finding rate	41%	15%	17%
2020'2021 BBSS	Tested	82	180	262
	Distribution tested	31%	69%	100%
	HIV positive Distribution	57% (n=35)	43% (n=26)	100% (n=61)
	Case-finding rate	43%	14%	24%

CONCLUSIONS: BBSS participation among older MSM increased from 2011 to 2020, but their burden of HIV has not improved over time. HIV programs should develop strategies tailored to the needs and preferences of older MSM. While their participation in the BBSS was lower than younger MSM, HIV case finding among older MSM suggests that reaching this subgroup with prevention, testing, and treatment services will be critical to achieving epidemic control.