Aruna Chandran

Global burden of acute lower respiratory infections due to respiratory syncytial virus in young children: a systematic review and meta-analysis

Summary Background The global burden of disease attributable to respiratory syncytial virus (RSV) remains unknown. We aimed to estimate the global incidence of and mortality from episodes of acute lower respiratory infection (ALRI) due to RSV in children younger than 5 years in 2005. Methods We estimated the incidence of RSV-associated ALRI in children younger than 5 years, stratified by age, using data from a systematic review of studies published between January, 1995, and June, 2009, and ten unpublished population-based studies. We estimated possible boundaries for RSV-associated ALRI mortality by combining case fatality ratios with incidence estimates from hospital-based reports from published and unpublished studies and identifying studies with population-based data for RSV seasonality and monthly ALRI mortality. Findings In 2005, an estimated 33·8 (95% CI 19·3–46·2) million new episodes of RSV-associated ALRI occurred worldwide in children younger than 5 years (22% of ALRI episodes), with at least 3·4 (2·8–4·3) million episodes representing severe RSV-associated ALRI necessitating hospital admission. We estimated that 66 000–199 000 children younger than 5 years died from RSV-associated ALRI in 2005, with 99% of these deaths occurring in developing countries. Incidence and mortality can vary substantially from year to year in any one setting. Interpretation Globally, RSV is the most common cause of childhood ALRI and a major cause of admission to hospital as a result of severe ALRI. Mortality data suggest that RSV is an important cause of death in childhood from ALRI, after pneumococcal pneumonia and Haemophilus influenzae type b. The development of novel prevention and treatment strategies should be accelerated as a priority. Funding WHO; Bill & Melinda Gates Foundation.

Global and regional burden of hospital admissions for severe acute lower respiratory infections in young children in 2010: a systematic analysis.

Summary Background The annual number of hospital admissions and in-hospital deaths due to severe acute lower respiratory infections (ALRI) in young children worldwide is unknown. We aimed to estimate the incidence of admissions and deaths for such infections in children younger than 5 years in 2010. Methods We estimated the incidence of admissions for severe and very severe ALRI in children younger than 5 years, stratified by age and region, with data from a systematic review of studies published between Jan 1, 1990, and March 31, 2012, and from 28 unpublished population-based studies. We applied these incidence estimates to population estimates for 2010, to calculate the global and regional burden in children admitted with severe ALRI in that year. We estimated in-hospital mortality due to severe and very severe ALRI by combining incidence estimates with case fatality ratios from hospital-based studies. Findings We identified 89 eligible studies and estimated that in 2010, 11·9 million (95% CI 10·3–13·9 million) episodes of severe and 3·0 million (2·1–4·2 million) episodes of very severe ALRI resulted in hospital admissions in young children worldwide. Incidence was higher in boys than in girls, the sex disparity being greatest in South Asian studies. On the basis of data from 37 hospital studies reporting case fatality ratios for severe ALRI, we estimated that roughly 265 000 (95% CI 160 000–450 000) in-hospital deaths took place in young children, with 99% of these deaths in developing countries. Therefore, the data suggest that although 62% of children with severe ALRI are treated in hospitals, 81% of deaths happen outside hospitals. Interpretation Severe ALRI is a substantial burden on health services worldwide and a major cause of hospital referral and admission in young children. Improved hospital access and reduced inequities, such as those related to sex and rural status, could substantially decrease mortality related to such infection. Community-based management of severe disease could be an important complementary strategy to reduce pneumonia mortality and health inequities. Funding WHO.

The Global Burden of Unintentional Injuries and an Agenda for Progress

According to the World Health Organization, unintentional injuries were responsible for over 3.9 million deaths and over 138 million disability-adjusted life-years in 2004, with over 90% of those occurring in low- and middle-income countries (LMIC). This paper utilizes the year 2004 World Health Organization Global Burden of Disease Study estimates to illustrate the global and regional burden of unintentional injuries and injury rates, stratified by cause, region, age, and gender. The worldwide rate of unintentional injuries is 61 per 100,000 population per year. Overall, road traffic injuries make up the largest proportion of unintentional injury deaths (33%). When standardized per 100,000 population, the death rate is nearly double in LMIC versus high-income countries (65 vs. 35 per 100,000), and the rate of disability-adjusted life-years is more than triple in LMIC (2,398 vs. 774 per 100,000). This paper calls for more action around 5 core areas that need research investments and capacity development, particularly in LMIC: 1) improving injury data collection, 2) defining the epidemiology of unintentional injuries, 3) estimating the costs of injuries, 4) understanding public perceptions about injury causation, and 5) engaging with policy makers to improve injury prevention and control.

The worldwide impact of the seven-valent pneumococcal conjugate vaccine.

Background: Pneumococcal conjugate vaccines (PCV) are emerging as one of the most promising means to prevent pediatric disease. The 7-valent PCV (PCV-7) has been extensively evaluated in clinical trials, and recent evidence from the introduction of PCV-7 through national immunization programs has demonstrated impact on pneumococcal disease. Methods: Clinical trials have shown PCV-7 to be effective against the more severe forms of pneumococcal infections: pneumonia and invasive pneumococcal disease (IPD), as well as overall child mortality. A review shows the tremendous impact PCV-7 has had to date, and the potential further benefi ts of the emerging multi-valent vaccines. Results: Since its introduction, the PCV-7 has substantially reduced the incidence of IPD, hospital admissions due to pneumonia and acute otitis media in numerous, mostly high income, low-disease burden countries. The reductions in IPD and pneumonia have also been observed among unvaccinated age groups in countries with routine use of PCV-7, demonstrating that PCV-7 provides herd immunity. Some settings observed an increase in rate of nonvaccine serotype IPD, yet rates of overall and vaccine-serotype IPD show marked reductions post–PCV-7 introduction. Limited data are available on the impact of PCV-7 in lower income countries. The available data from effi cacy trials from The Gambia and South Africa suggest that PCV-7 will have substantial impact on reducing pneumococcal disease. Conclusion: PCV-7 has shown dramatic reduction in disease and mortality rates in the countries in which it has been introduced. The newly introduced 10-valent and 13-valent pneumococcal vaccines are expected to have substantial disease impact, but monitoring is essential to determine their true impact and sustain further introduction of pneumococcal conjugate vaccines.

Progress and barriers for the control of diarrhoeal disease

Discovery of intestinal sodium-glucose transport was the basis for development of oral rehydration solution, and was hailed as potentially the most important medical advance of the 20th century. Before widespread use of oral rehydration solution, treatment for diarrhoea was restricted to intravenous fluid replacement, for which patients had to go to a health-care facility to access appropriate equipment. These facilities were usually neither available nor reasonable to use in the resource-poor settings most affected by diarrhoea. Use of oral rehydration solution has stagnated, despite being effective, inexpensive, and widely available. Thus, diarrhoea continues to be a leading cause of child death with consistent mortality rates during the past 5 years. New methods for prevention, management, and treatment of diarrhoea-including an improved oral rehydration formulation, zinc supplementation, and rotavirus vaccines-make now the time to revitalise efforts to reduce diarrhoea mortality worldwide.

Long-term Sequelae of Childhood Bacterial Meningitis An Underappreciated Problem

Background: Numerous sequelae have been noted in survivors of bacterial meningitis; however, few studies document sequelae for several years following a childhood episode of bacterial meningitis. In addition, studies generally focus on the more commonly found sequelae. To review the known information and highlight this gap, this article presents a comprehensive literature review of the long-term (≥5 years of follow-up) sequelae of childhood bacterial meningitis. Methods: A systematic literature search was conducted between December 2009 and February 2010. English-language articles published between January 1970 and January 2010 were selected for screening. Articles were included if the subjects were between the ages of 1 month and <18 years at the time of diagnoses of meningitis. Results: A total of 1433 children who were survivors of childhood bacterial meningitis were evaluated for sequelae after the time of discharge. Of these children, 705 (49.2%) were reported to have 1 or more long-term sequelae. A majority of reported sequelae were behavioral and/or intellectual disorders (n = 455, 45.0%). Hearing changes accounted for 6.7% (n = 68) of sequelae and gross neurologic deficits accounted for 14.3% (n = 145). Discussion: A majority of childhood bacterial meningitis survivors with long-term sequelae that are documented in the literature have academic and behavioral limitations. While neurologic deficits may resolve over time, subtle behavioral deficits may not be appreciated initially and may continue to affect survivors for many years. Further studies are needed to quantify the true societal and economic burden of long-term sequelae as well as fully understand the breadth of types of sequelae that survivors experience.

Care Seeking for Neonatal Illness in Low- and Middle- Income Countries: A Systematic Review

Hadley Herbert and colleagues systematically review newborn care-seeking behaviors by caregivers in low- and middle-income countries.

Randomized, controlled trial efficacy of pneumococcal conjugate vaccine against otitis media among Navajo and White Mountain Apache infants.

We report the phase III trial efficacy of 7-valent pneumococcal conjugate vaccine against clinical and culture proven otitis media (OM) among Navajo and White Mountain Apache infants. Efficacy was −0.4% (95% CI: −19.4 to 15.6) for clinically-diagnosed OM, 5.1% (95% CI: −51.5 to 40.6) for severe OM, and 64% (95% CI: −34% to 90%) for vaccine serotype pneumococcal OM suggesting that this vaccine is efficacious for pneumococcal OM in this high risk population.

Prevention of rotavirus gastroenteritis in infants and children: rotavirus vaccine safety, efficacy, and potential impact of vaccines

Rotavirus infection is the most common cause of severe gastroenteritis globally, with greater than 86% of deaths occurring in low-income and middle-income countries. There are two rotavirus vaccines currently licensed in the United States and prequalified by the World Health Organization. RV1 is a monovalent attenuated human rotavirus strain, given orally in two doses. RV5 is a pentavalent human-bovine reassortant rotavirus vaccine, given orally in three doses. A third rotavirus vaccine, LLV, is a lamb rotavirus strain given orally as a single dose, which is currently available only in China. RV1 and RV5 have been shown to be highly efficacious in developed countries, and initial results from trials in Africa and Asia are promising as well. At least three other vaccines are in development, which are being developed by manufacturers of developing countries. Further studies are needed to clarify issues including administration of oral rotavirus vaccines with breastfeeding and other oral vaccines, and alterations in dosing schedule. Using new data on global diarrheal burden, rotavirus is estimated to cause 390,000 deaths in children younger than 5 years. Should rotavirus vaccines be introduced in the routine immunization programs of all countries, a potential of 170,000 deaths could be prevented annually. The largest impact on mortality would be seen in low-income and middle-income countries, despite poor immunization coverage and lower efficacy. Therefore, international efforts are needed to ensure that rotavirus vaccines reach the populations with highest burden of rotavirus disease.

Supporting new vaccine introduction decisions: Lessons learned from the Hib Initiative experience

The introduction of Haemophilus influenzae type b (Hib) vaccine in developing countries has suffered from a long delay. Between 2005 and 2009, a surge in Hib vaccine adoption took place, particularly among GAVI-eligible countries. Several factors contributed to the increase in Hib vaccine adoption, including support provided by the Hib Initiative, a project funded by the GAVI Alliance in 2005 to accelerate evidence-informed decisions for use of Hib vaccine. This paper reviews the strategy adopted by the Hib Initiative and the lessons learned in the process, which provide a useful model to accelerate uptake of other new vaccines.