Bordetella pertussis -related Respiratory Deaths in Infants From 4 Days to 6 Months of Age, Results From a 3-Year, Prospective Postmortem Surveillance Study in Lusaka, Zambia.

BACKGROUND

Since the 1990s, a remarkable decline in infant and child mortality has occurred. Continued progress in reducing mortality will need to focus on early infant and neonatal mortality and on less common diseases than pneumonia, diarrhea and malnutrition. One of the candidate diseases for focus is Bordetella pertussis , the principal cause of "whooping cough."

METHODS

We conducted a study to measure the burden of deaths and calculate the population-attributable fraction of deaths due to B. pertussis . We collected postmortem nasopharyngeal swabs from subjects who died at the University Teaching Hospital or in the community and were brought to the University Teaching Hospital morgue 4 days to < 6 months of age. Infection with B. pertussis was determined with polymerase chain reaction testing. We assigned respiratory cause of death from the medical record or from a verbal autopsy collected from caregivers.

RESULTS

From August 2017 to August 2020, we collected nasopharyngeal samples from 2236 deceased subjects. Respiratory deaths were assigned to 29.0% of the deaths; 39.5% of community deaths were attributed to respiratory causes. Using 2 definitions of polymerase chain reaction positivity, the prevalence of B. pertussis in infant deaths was between 5.69 per 1000 deaths (95% confidence interval, 2.57-8.80) and 25.81 per 1000 deaths (95% confidence interval, 19.24-32.38). Pertussis accounted for between 0.22% and 0.81% of all infant deaths.

CONCLUSIONS

In this population of infants, B. pertussis was a minor source of all-cause infant mortality. Our analysis does not support the need for further steps for population-level preventive strategies for the control of B. pertussis .