Seroprevalence of cytomegalovirus among pregnant women in Windhoek, Namibia, 2016

Background. Seroprevalence of cytomegalovirus (CMV) is high in developing countries. However, a pregnant woman’s immunity does not necessarily protect her baby against congenital CMV infection.  Objectives. To determine the seroprevalence of CMV among pregnant women attending a public antenatal clinic (Windhoek Central Hospital, Namibia) and subsequently determine the risk of vertical transmission and congenital CMV infection.  Methods. Blood samples and demographic information were collected from 344 pregnant women (age range 15 - 48 years). Serum was tested for anti-CMV IgG and IgM using an automated chemiluminescence assay, and an ELISA was used to assess specific IgG avidity. Fisher’s exact test was used to determine associations among variables.  Results. Seroprevalence of anti-CMV IgG was found to be 100% across the study population, with positive or grey-zone anti-CMV IgM results found in 11 women (3.2%). Specific IgG avidity was high in all cases. Neither maternal nor gestational age was positively associated with a positive or grey-zone IgM result. Parity was significantly associated with CMV IgM seroprevalence, with the highest level observed in women who had had one previous pregnancy.  Conclusion. This was the first study to investigate seroprevalence of CMV in Namibia. Despite the high seroprevalence among pregnant women, the burden of congenital CMV infection may b e carried by infants in the Namibian population. This may contribute to long-term disabilities, especially sensorineural hearing loss. Further studies are needed to determine the prevalence of congenital CMV in Namibia.