The apparent burden of unexplained sudden infant deaths in Lusaka, Zambia: Findings from analysis of verbal autopsies

Abstract

Background: The contribution of sudden unexpected infant death (SUID) has received little attention in global health. The objective of this study was to estimate the burden of SUID in Lusaka, Zambia. Methods: Verbal autopsies were conducted on infants who died in Lusaka, between 2017 and 2020.  From these, we performed a qualitative analysis of the free text narratives of the final series of events leading to each infant’s death and classified these as symptomatic deaths or SUID. Any narrative that described an infant who was otherwise healthy with no antecedent illness prior to death and found dead in bed after a sleep episode was classified as SUID. We used logistic regression to test for statistical differences between asymptomatic deaths and SUIDs on key infant, maternal and other risk factors of SUIDs. Results: Eight hundred and nine verbal autopsies were conducted with families of decedent infants younger than six months of age. A total of 92.6% (749/809) had presented with symptoms prior to death, whereas 7.4% (60/809) died without preceding symptoms or obvious cause of death. Of these, 16/60 were compatible with accidental suffocation deaths, and 54/60 appeared to be sudden infant death syndrome.  SUID deaths were concentrated in infants younger than two months of age with peak age of one to two months. Age at death was the only significant factor in multivariate analysis. Infants aged between one and two months had 2.84 increased odds of suspected SUIDs compared to infants in the first month of life (aOR = 2.84, 95% CI: 1.31, 6.16). Conclusions: Our findings suggest SUID could be accounting for a significant proportion of infant deaths in Zambia, but this cause of infant mortality is going unrecognized. Public health interventions in Zambia, and Africa more broadly, are likely overlooking SUIDs as an important cause of infant mortality.