Access to HIV Services for Mobile and Migrant Populations in Antigua

MAPPING METHODOLOGY
Population
Due to numerous findings that suggested that vulnerable migrant and mobile populations
included men who have sex with men (MSM) and commercial sex workers (CSW), it was
decided that those populations would be polled to understand their perception of their ease of
access to services and to get a better understanding of which organizations are most utilized by
these core groups.
Sample Size
Commercial Sex Workers sample size – 114
Men who have sex with men sample size – 95
Justification for sample size
The Ministry of Tourism estimates Antigua’s resident population as approximately 86,295 based
on the 2011 census with the migrant population being 22% of that figure. Men who have sex
with men are estimated to be about 4% of the population which is 3451.The migrant population
is approximately 22 % of the general population, therefore, the migrant MSM population was
tentatively estimated as 22% of 3451, which is 759. The number of documented men who have
sex with men is listed as 300, so that number was used to draw a sample using the formula
included in EPIINFO programs from CDC. If the population size for MSM is 300, and setting
the worst scenario with an expected frequency of 10% of HIV prevalence, and the confidence
limits in 5%, the sample to be drawn at a confidence level of 95% is 95. Hence 85 members of
the MSM population will be polled.
The National AIDS Program receives quarterly reports from the Caribbean HIV and AIDS
Alliance (CHAA) with the number of sex workers that they provide outreach services to. The
documented amount of sex workers served by CHAA is 250. Using a similar formula of a 10%
of HIV prevalence and confidence limits at 5%, the confidence level of the sample at 95% would
be 89. Because several studies have indicated that the numbers were greater, 25 more was added
(oversampled) to the 89 for a total of 114 sex workers to be interviewed.
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