In Western and Central Africa (WCA), survey data suggest that HIV prevalence among women aged 20−29 years old is higher than men of the same age in all countries and between 5 and 9 times higher in some countries such as Gambia, Côte d'Ivoire and Ghana.
By ages 40−49, men have "caught up" to women and have similar HIV prevalence values. Exceptions to this are the Democratic Republic of Congo, Ghana and Gabon where prevalence among women is still almost twice as high.
. Possible reasons for this difference include the high rates of voluntary medical male circumcision in the WCA countries. Male circumcision was shown in three clinical trials in South Africa, Uganda and Kenya to have a 60% protective effective on female to male HIV transmission. Other possible reasons might be the very low use of condoms and low uptake of antiretroviral therapy among men.