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Pneumonia accounts for 18 per cent of all deaths of children under five worldwide each year, with children in Sub-Saharan Africa and South Asia succumbing to the disease the most, according to the World Health Organisation.
Kenya introduced a vaccine called PCV10 against pneumonia in January 2011, according to the study published in the March issue of the Lancet Global Health, which experts say offers some of the first evidence of its success in children.
“The study shows that there is considerable improvement in child health associated with the implementation of a PCV10 programme, providing important evidence for policymakers in Africa as they confront the challenge of sustaining immunisation programmes independently,” says Anthony Scott, corresponding author of the study and professor of vaccine epidemiology at the UK-based London School of Hygiene and Tropical Medicine.
“The study shows that there is considerable improvement in child health associated with the implementation of a PCV10 programme, providing important evidence for policymakers,”
Anthony Scott, London School of Hygiene and Tropical Medicine
The KEMRI-Wellcome Trust Research Programme in Kenya conducted the study in Kenya’s Kilifi County in partnership with other institutions.
Shirine Voller, manager of the Epidemiology and Demography Department at the KEMRI Wellcome Trust Research Programme, tells SciDev.Net that when Kenya was planning to introduce the vaccine into its routine immunisation schedule, there was very limited evidence about its use and impact in Sub-Saharan Africa.
Researchers linked records of severe or very severe childhood pneumonia at Kenya’s Kilifi County Hospital from 2002 to 2015 to the Kilifi Health and Demographic Surveillance System, which has a population of 45,000 children younger than five years.
“The study was initiated before [the vaccine] was introduced in Kenya, meaning it was possible to make a before-after comparison of the incidence of pneumonia hospitalisations in Kilifi, and therefore to show what impact the vaccine has had in reducing the burden of pneumonia,” she says.
According to the study, the introduction of the vaccine led to a reduction of new childhood pneumonia cases from 1,220 per 100,000 to 891 per 100,000.
Voller adds that many countries in Sub-Saharan Africa have introduced similar vaccines against pneumonia, but this study represents some of the first robust evidence of the impact of vaccination on the incidence of childhood pneumonia in the region.“The KEMRI-Wellcome Trust Research Programme is currently engaging with the Kenya National Immunisation Technical Advisory Group to share our findings about the [vaccine’s] impact and cost-effectiveness,” adds Voller.
Yap Boum II, the regional representative for Epicentre, the research arm of Médecins sans Frontières, says that the findings of the study are significant.
“Almost 30 per cent reduction [of new cases of pneumonia in children] is huge considering all the implications in terms of vaccine effectiveness and also all the logistics needed to make the vaccine available,” he tells SciDev.Net.
Anthony Scott and others Effect of 10-valent pneumococcal conjugate vaccine on the incidence of radiologically-confirmed pneumonia and clinically-defined pneumonia in Kenyan children: an interrupted time-series analysis (Lancet Global Health, March 2019