PLoS One. 2017 Jan 4;12(1):e0168209. doi: 10.1371/journal.pone.0168209. eCollection 2017.

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

McCollum ED^1,2, Nambiar B¹, Deula R³, Zadutsa B³, Bondo A³, King C¹, Beard J¹, Liyaya H³, Mankhambo L³, Lazzerini M⁴, Makwenda C³, Masache G³, Bar-Zeev N^5,6, Kazembe PN⁷, Mwansambo C⁸, Lufesi N⁹, Costello A¹, Armstrong B¹⁰, Colbourn T¹.

Author information

• ¹Institute for Global Health, University College London, London, United Kingdom.
• ²Department of Pediatrics, Division of Pulmonology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America.
• ³Parent and Child Health Initiative Trust, Lilongwe, Malawi.
• ⁴WHO Collaborating Centre for Maternal and Child Health, Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy.
• ⁵Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, University of Malawi, Blantyre, Malawi.
• ⁶Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
• ⁷Baylor College of Medicine Childrens Foundation, Lilongwe, Malawi.
• ⁸Ministry of Health, Lilongwe, Malawi.
• ⁹Community Health Sciences Unit, Ministry of Health, Lilongwe, Malawi.
• ¹⁰Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, United Kingdom.

Abstract below; full text is at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0168209

BACKGROUND:

The pneumococcal conjugate vaccines (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 FINDINGS:

Between 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.

CONCLUSIONS:

Thirty 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.