Incidence and risk factors for neonatal tetanus in admissions to Kilifi County Hospital, Kenya

Abstract

Background: Neonatal Tetanus (NT) is a preventable cause of mortality and neurological sequelae that occurs at higher incidence in resource-poor countries, presumably because of low maternal immunisation rates and unhygienic cord care practices. We aimed to determine changes in the incidence of NT, characterize and investigate the associated risk factors and mortality in a prospective cohort study including all admissions over a 15-year period at a County hospital on the Kenyan coast, a region with relatively high historical NT rates within Kenya.

Methods: We assessed all neonatal admissions to Kilifi County Hospital in Kenya (1999-2013) and identified cases of NT (standard clinical case definition) admitted during this time. Poisson regression was used to examine change in incidence of NT using accurate denominator data from an area of active demographic surveillance. Logistic regression was used to investigate the risk factors for NT and factors associated with mortality in NT amongst neonatal admissions. A subset of sera from mothers (n = 61) and neonates (n = 47) were tested for anti-tetanus antibodies.

Results: There were 191 NT admissions, of whom 187 (98%) were home deliveries. Incidence of NT declined significantly (Incidence Rate Ratio: 0.85 (95% Confidence interval 0.81-0.89), P<0.001) but the case fatality (62%) did not change over the study period (P = 0.536). Younger infant age at admission (P = 0.001) was the only independent predictor of mortality. Compared to neonatal hospital admittee controls, the proportion of home births was higher among the cases. Sera tested for antitetanus antibodies showed most mothers (50/61, 82%) had undetectable levels of antitetanus antibodies, and most (8/9, 89%) mothers with detectable antibodies had a neonate without protective levels.

Conclusions: Incidence of NT in Kilifi County has significantly reduced, with reductions following immunisation campaigns. Our results suggest immunisation efforts are effective if sustained and efforts should continue to expand coverage.

Fig 1. Incidence and case fatality of neonatal tetanus in Kilifi County Hospital.

Incidence was computed as the number of Neonatal Tetanus (NT) cases within the KHDSS divided by the number of live births in that year. There were zero NT admissions in 2013 and therefore no deaths. NT campaigns started in 2002 in an effort by the Kenya Ministry of Health to abate NT. Major campaigns to women of child bearing age were carried out in 2002, 2008 and 2013 as shown by the arrows. The red dashed line is the WHO target of less than one NT cases per 1000 live births. The case fatality is the proportion of neonatal tetanus admissions discharged dead.