International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases 2016 5 24() pii 10.1016/j.ijid.2016.05.020
Namibia experienced a large measles outbreak starting in 2009, with 38% of reported cases in adults, including women of reproductive age. We assessed population immunity among pregnant women, to determine if immunization activities were needed in adults to achieve measles elimination in Namibia.
We tested 1,708 and 2,040 specimens for measles immunoglobulin G antibody from Namibian pregnant women aged 15-44 years sampled from the 2008 and 2010 National HIV Sentinel Survey, respectively. We determined the proportion of women seropositive overall and by 5-year age strata, and analyzed factors associated with seropositivity by logistic regression, including age, facility type, gravidity, HIV status, and urban/rural status. We tested for any difference in seropositivity between 2008 and 2010.
In both analysis years, measles seropositivity was lower in 15-19 year olds (77%) and 20-24 year olds (85-87%) and higher in 25-44 year olds (90%-94%) (p<0.001, 2008; p<0.001, 2010). Overall measles seropositivity did not differ between 2008 (87%) and 2010 (87%) (p=0.7). HIV status did not affect seropositivity. CONCLUSIONS
Late in a large measles outbreak, 13% of pregnant women in Namibia, and almost one in four 15-19 year old pregnant women, remained measles-susceptible. In Namibia, immunization campaigns with measles-containing vaccine should be considered for adults.