Prevalence of Congenital Cytomegalovirus Infection Among Neonates Admitted at the Kenyatta National Hospital

Abstract

Background and Study Utility Human Cytomegalovirus (CMV) is a leading cause of congenital infections worldwide and a leading cause of childhood hearing loss and neurodevelopmental delay. The burden of disease is in developing countries yet only few prevalence studies have been carried out in these regions. Studies in high income countries reveal prevalence ranges from 0.2 – 2.2%. The vast majority of neonates present with asymptomatic infection at birth and approximately 15% of these will develop long term neurological sequelae. Symptomatic infection occurs in 10 – 15% of the neonates with a mortality rate of 10%. A higher prevalence of congenital CMV infection has been shown in developing countries of 4 – 17.8%. Despite this, the prevalence in Kenya has not been investigated. Study Design and Objectives This was a short longitudinal survey aimed at determining the prevalence, clinical spectrum of disease and short term mortality of CMV among neonates admitted to the new born unit (NBU) of Kenyatta National Hospital (KNH). Methods We included all newborns admitted to the KNH NBU at 0 – 48 hours of life whose parents consented. A baseline history and examination were performed. Thereafter, the initial saliva sample was collected to perform a CMV Polymerase Chain Reaction (PCR) test. Patients were followed up at 2 weeks of life and a second saliva sample was then obtained from the neonates who initially tested CMV negative. A second follow up for the neonates who tested CMV positive was at 4 weeks of life. Information on morbidity during the first month was abstracted from their medical records for in-patients and by interview for illness post discharge; this was to determine the morbidity and mortality of the CMV infected newborns. Data was entered using Microsoft excel and software analysed using Stata version 11.2. Results We enrolled 223 newborns aged between 0-48 hours, of these, 131 (58.7%) were male; 130 (58.3%) were term with a median gestation of 37 weeks (33, 40); 118 (52.9%) were of normal weight at term with a median birth weight of 2600g (1695, 3210). Median age of the mothers was 25 years (22, 28). The most common mode of delivery was spontaneous vertex delivery at 58.3%, other modes of delivery accounted for 41.7%. Of the 223 newborns enrolled, 5 were CMV positive before 48 hours giving a prevalence of 2.2%% (95% CI 0.7 – 5.2). An additional 10, who were previously negative at birth became CMV positive by age 2 weeks, giving a 2 week prevalence of 8.6% (95% CI 4.2 – 15.3) and overall prevalence of 6.7% (95% CI 3.8 – 10.8). Of the CMV positive newborns, 5(33.3%) were symptomatic, 10(66.7%) were asymptomatic. The clinical spectrum of disease in the symptomatic newborns included; prematurity, IUGR, jaundice, hepatosplenomegaly, petechiae, pallor, thrombocytopenia, seizures, microcephaly and respiratory distress. Four of the CMV positive newborns died before age 4 weeks giving a mortality rate of 26.7%. Mortality was high among symptomatic CMV positive newborns (3 of 5, 60%) and lower among asymptomatic newborns (1 of 10, 10%) giving a relative risk for death of 8.3 (95% CI 1.2 - 58.1), P = 0.03. Conclusions and Recommendations The prevalence of congenital CMV among newborns hospitalised in KNH is 6.7% with majority of the neonates presenting with asymptomatic disease. Symptomatic disease occurred in one third and was associated with an eight fold increased mortality risk compared to asymptomatic infection. We recommend that all newborns should be screened for congenital CMV due to the devastating short and long term consequences of the disease. We also recommend a study on the long-term outcome of children with congenital CMV.