The prevalence and clinical characteristics of pertussis-associated pneumonia among infants in Botswana

Bahaa Abu-Raya,Andrew P Steenhoff,Samir S Shah,Kristen A Feemster,Mohamed Zaakir Patel,Coleen K Cunningham,Marek Smieja,Tonya Arscott-Mills,David M Goldfarb,Kathy Luinstra,Matthew S Kelly,Manish Sadarangani,Melissa Richard-Greenblatt

doi:10.1186/s12887-019-1820-0

Abstract

BackgroundThere are scant data on the prevalence and clinical course of pertussis disease among infants with pneumonia in low- and middle-income countries. While pertussis vaccination coverage is high (≥90%) among infants in Botswana, human immunodeficiency virus (HIV) infection affects nearly one-third of pregnancies.We aimed to evaluate the prevalence and clinical course of pertussis disease in a cohort of HIV-unexposed uninfected (HUU), HIV-exposed uninfected (HEU), and HIV-infected infants with pneumonia in Botswana.MethodsWe recruited children 1–23 months of age with clinical pneumonia at a tertiary care hospital in Gaborone, Botswana between April 2012 and June 2016. We obtained nasopharyngeal swab specimens at enrollment and tested these samples using a previously validated in-house real-time PCR assay that detects a unique sequence of the porin gene of Bordetella pertussis.ResultsB. pertussis was identified in 1/248 (0.4%) HUU, 3/110 (2.7%) HEU, and 0/33 (0.0%) HIV-infected children. All pertussis-associated pneumonia cases occurred in infants 1–5 months of age (prevalence, 1.0% [1/103] in HUU and 4.8% [3/62] in HEU infants). No HEU infants with pertussis-associated pneumonia were taking cotrimoxazole prophylaxis at the time of hospital presentation. One HUU infant with pertussis-associated pneumonia required intensive care unit admission for mechanical ventilation, but there were no deaths.ConclusionsThe prevalence of pertussis was low among infants and young children with pneumonia in Botswana. Although vaccination against pertussis in pregnancy is designed to prevent classical pertussis disease, reduction of pertussis-associated pneumonia might be an important additional benefit.

Highlights

There are scant data on the prevalence and clinical course of pertussis disease among infants with pneumonia in low- and middle-income countries
We excluded children with chronic medical conditions predisposing to pneumonia, hospitalization within the previous 14 days, a diagnosis of asthma, or wheezing with resolution of chest wall indrawing after ≤2 treatments with a bronchodilator
In the analyses presented we used a previously validated highly sensitive and specific in-house real-time Polymerase chain reaction (PCR) assay that detects a unique sequence of the porin gene of B. pertussis [8]

Summary

Introduction

There are scant data on the prevalence and clinical course of pertussis disease among infants with pneumonia in low- and middle-income countries. We aimed to evaluate the prevalence and clinical course of pertussis disease in a cohort of HIV-unexposed uninfected (HUU), HIV-exposed uninfected (HEU), and HIV-infected infants with pneumonia in Botswana. The burden of pertussis disease in low- and middleincome countries (LMICs) is difficult to estimate and poorly recorded. This may be due to the limited availability of diagnostic assays for B. pertussis detection and under recognition of pertussis infection that is not associated with classical clinical features [2]. Several factors that might affect the risk and severity of pertussis disease among infants merit special consideration in LMICs. Of particular concern is maternal human immunodeficiency

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