Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: global, regional, and national estimates for 2000–15

Abstract

SummaryBackgroundPneumococcal conjugate vaccine (PCV) and Haemophilus influenzae type b (Hib) vaccine are now used in most countries. To monitor global and regional progress towards improving child health and to inform national policies for disease prevention and treatment, we prepared global, regional, and national disease burden estimates for these pathogens in children from 2000 to 2015.MethodsUsing WHO and Maternal and Child Epidemiology Estimation collaboration country-specific estimates of pneumonia and meningitis mortality and pneumonia morbidity from 2000 to 2015, we applied pneumococcal and Hib cause-specific proportions to estimate pathogen-specific deaths and cases. Summary estimates of the proportion of pneumonia deaths and cases attributable to these pathogens were derived from four Hib vaccine and six PCV efficacy and effectiveness study values. The proportion of meningitis deaths due to each pathogen was derived from bacterial meningitis aetiology and adjusted pathogen-specific meningitis case–fatality data. Pneumococcal and Hib meningitis cases were inferred from modelled pathogen-specific meningitis deaths and literature-derived case–fatality estimates. Cases of pneumococcal and Hib syndromes other than pneumonia and meningitis were estimated using the ratio of pathogen-specific non-pneumonia, non-meningitis cases to pathogen-specific meningitis cases from the literature. We accounted for annual HIV infection prevalence, access to care, and vaccine use.FindingsWe estimated that there were 294 000 pneumococcal deaths (uncertainty range [UR] 192 000–366 000) and 29 500 Hib deaths (18 400–40 700) in HIV-uninfected children aged 1–59 months in 2015. An additional 23 300 deaths (15 300–28 700) associated with pneumococcus and fewer than 1000 deaths associated Hib were estimated to have occurred in children infected with HIV. We estimate that pneumococcal deaths declined by 51% (7–74) and Hib deaths by 90% (78–96) from 2000 to 2015. Most children who died of pneumococcus (81%) and Hib (76%) presented with pneumonia. Less conservative assumptions result in pneumococcccal death estimates that could be as high as 515 000 deaths (302 000–609 000) in 2015. Approximately 50% of all pneumococcal deaths in 2015 occurred in four countries in Africa and Asia: India (68 700 deaths, UR 44 600–86 100), Nigeria (49 000 deaths, 32 400–59 000), the Democratic Republic of the Congo (14 500 deaths, 9300–18 700), and Pakistan (14 400 deaths, 9700–17 000]). India (15 600 deaths, 9800–21 500), Nigeria (3600 deaths, 2200–5100), China (3400 deaths, 2300–4600), and South Sudan (1000 deaths, 600–1400) had the greatest number of Hib deaths in 2015. We estimated 3·7 million episodes (UR 2·7 million–4·3 million) of severe pneumococcus and 340 000 episodes (196 000–669 000) of severe Hib globally in children in 2015.InterpretationThe widespread use of Hib vaccine and the recent introduction of PCV in countries with high child mortality is associated with reductions in Hib and pneumococcal cases and deaths. Uncertainties in the bur...

Haemophilus influenzae type b vaccination and anthropometric, cognitive, and schooling outcomes among Indian children

“…The burden of Hib disease in India was high in 2000—the only year during early life of the YLS cohort for which such data are available. Estimates from two modeling studies and the World Health Organization range from 2 to 4.5 million Hib cases in India in 2000, most of which were Hib pneumonia . Two‐thirds of Hib cases are known to occur in children under the age of 2 years, implying that a substantial proportion of the under‐2 cohort of 36.2 million Indian children at that time was affected .…”

“…Worldwide, 191 countries had adopted the Hib vaccine by 2017, with an estimated 72% of Hib third dose (Hib3)—which promotes durability following the immune response built by the first two doses—coverage among 12‐ to 23‐month‐old children . However, coverage varied widely, from 94% in high‐income countries to 81%, 77%, and 41%, respectively, in lower‐middle‐, low‐, and upper‐middle‐income countries, and 975,000 cases and 29,800 deaths from Hib still occurred among 1‐ to 59‐month‐old children worldwide in 2015 . India's Hib3 coverage rates among children under the age of 2 years increased from 20% in 2013 to 88% in 2017, but its burden of disease remains the highest in the world .…”

“…However, coverage varied widely, from 94% in high‐income countries to 81%, 77%, and 41%, respectively, in lower‐middle‐, low‐, and upper‐middle‐income countries, and 975,000 cases and 29,800 deaths from Hib still occurred among 1‐ to 59‐month‐old children worldwide in 2015 . India's Hib3 coverage rates among children under the age of 2 years increased from 20% in 2013 to 88% in 2017, but its burden of disease remains the highest in the world . Funding for India's national immunization program remains inadequate.…”

“…Haemophilus influenzae type b (Hib) is a bacterial pathogen that causes pneumonia and bacterial meningitis and, to a lesser extent, epiglottitis and other infections among children under age 5 . Although the national burden of Hib has declined by 84% since 2000, India continues to have the largest number of Hib cases and associated deaths in the world . An estimated 337,270 Hib cases and 15,634 deaths occurred among Indian children aged 1–59 months in 2015; pneumonia and meningitis comprised 99% of the cases.…”

“…Although the national burden of Hib has declined by 84% since 2000, India continues to have the largest number of Hib cases and associated deaths in the world . An estimated 337,270 Hib cases and 15,634 deaths occurred among Indian children aged 1–59 months in 2015; pneumonia and meningitis comprised 99% of the cases. The Hib vaccine has been privately available in India since 1997.…”