Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study

Abstract

BackgroundThe pneumococcal conjugate vaccine’s (PCV) impact on childhood pneumonia during programmatic conditions in Africa is poorly understood. Following PCV13 introduction in Malawi in November 2011, we evaluated the case burden and rates of childhood pneumonia.Methods and FindingsBetween January 1, 2012-June 30, 2014 we conducted active pneumonia surveillance in children <5 years at seven hospitals, 18 health centres, and with 38 community health workers in two districts, central Malawi. Eligible children had clinical pneumonia per Malawi guidelines, defined as fast breathing only, chest indrawing +/- fast breathing, or, ≥1 clinical danger sign. Since pulse oximetry was not in the Malawi guidelines, oxygenation <90% defined hypoxemic pneumonia, a distinct category from clinical pneumonia. We quantified the pneumonia case burden and rates in two ways. We compared the period immediately following vaccine introduction (early) to the period with >75% three-dose PCV13 coverage (post). We also used multivariable time-series regression, adjusting for autocorrelation and exploring seasonal variation and alternative model specifications in sensitivity analyses.The early versus post analysis showed an increase in cases and rates of total, fast breathing, and indrawing pneumonia and a decrease in danger sign and hypoxemic pneumonia, and pneumonia mortality. At 76% three-dose PCV13 coverage, versus 0%, the time-series model showed a non-significant increase in total cases (+47%, 95% CI: -13%, +149%, p = 0.154); fast breathing cases increased 135% (+39%, +297%, p = 0.001), however, hypoxemia fell 47% (-5%, -70%, p = 0.031) and hospital deaths decreased 36% (-1%, -58%, p = 0.047) in children <5 years. We observed a shift towards disease without danger signs, as the proportion of cases with danger signs decreased by 65% (-46%, -77%, p<0.0001). These results were generally robust to plausible alternative model specifications.ConclusionsThirty months after PCV13 introduction in Malawi, the health system burden and rates of the severest forms of childhood pneumonia, including hypoxemia and death, have markedly decreased.

The prevalence and risk factors for acute respiratory infections in children aged 0‐59 months in rural Malawi: A cross‐sectional study

“…Not being vaccinated against PCV or having EPI vaccinations were protective factors for pneumonia, although this was not statistically significant, and coverage of PCV in this study was higher than estimates in neighbouring districts . It is expected that PCV vaccination protects against severe ARI.…”

“…Furthermore, our study might underestimate the annual prevalence if not all affected children access health care or if there is variation in documentation in health passports. This reflects data on severe pneumonia in Malawi in which 24% of cases were identified by HSAs in the community, not in hospitals or health centres …”

“…The cross‐sectional study design has limitations. Data were collected during the rainy season, and pneumonia cases peak from January to March, possibly inflating the point prevalence of ARI. The period prevalence should not be affected.…”

“…Therefore, research determining the generalizability of these risk factors to children in the community was needed. The 13‐valent pneumococcal conjugate vaccination (PCV13) was introduced in Malawi in November 2011 and has been shown to decrease severe childhood pneumonia by 65% in both hospitalized and community cases . Malawi has a national programme for PCV, and recent data suggest that 49.9% of children under five receive PCV, but the uptake in Mangochi is unknown.…”

Typhoid conjugate vaccines: making vaccine history in Africa

“…Considering 36 of the 47 GAVI-eligible countries are within Africa, this presents a huge opportunity for the continent. Looking at recent introductions of new vaccines into the continent, rotavirus and pneumococcal conjugate vaccines have been introduced into 29 and 33 different GAVI-eligible African countries, respectively, often ahead of schedule and demonstrating significant impact on disease burden [24][25][26].…”