SummaryBackgroundThe 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.MethodsWe 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by age, using data from a systematic review of studies published between January, 1995, and June, 2009, and ten unpublished population-based studies.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mortality by combining case fatality ratios with incidence estimates from hospital-based reports from published and unpublished studies and identifying studies with population-based data for RSV seasonality and monthly ALRI mortality.FindingsIn 2005, an estimated 33·8 (95% CI 19·3–46·2)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.InterpretationGlobally, 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.FundingWHO; Bill & Melinda Gates Foundation.

We report estimates of incidence of respiratory syncytial virus (RSV) infection during the first year of life for a birth cohort from rural, coastal Kenya. A total of 338 recruits born between 21 January 2002 and 30 May 2002 were monitored for symptoms of respiratory infection by home visits and hospital referrals. Nasal washings were screened by use of immunofluorescence. From 311 child-years of observation (cyo), 133 RSV infections were found, of which 48 were lower respiratory tract infections (LRTIs) and 31 were severe LRTIs, resulting in 4 hospital admissions. There were 121 primary RSV infections (248 cyo), of which 45 were LRTIs and 30 were severe LRTIs, resulting in 4 hospital admissions; there was no association with age. RSV contributed significantly to total LRTI disease in this vaccine-target group.

Aims: To provide a comprehensive description of young infant admissions to a first referral level health facility in Kenya. These data, currently lacking, are important given present efforts to standardise their care through the integrated management of childhood illness (IMCI) and for prioritising both health care provision and disease prevention strategies. Methods: Prospective, 18 month observational study in a Kenyan district hospital of all admissions less than 3 months of age to the paediatric ward. Results: A total of 1080 infants were studied. Mortality was 18% overall, though in those aged 0-7 days it was 34%. Within two months of discharge a further 5% of infants aged <60 days on admission had died. Severe infection and prematurity together accounted for 57% of inpatient deaths in those aged <60 days, while jaundice and tetanus accounted for another 27%. S pneumoniae, group B streptococcus, E coli, and Klebsiella spp. were the most common causes of invasive bacterial disease. Hypoxaemia, hypoglycaemia, and an inability to feed were each present in more than 20% of infants aged 0-7 days. Both hypoxaemia and the inability to feed were associated with inpatient death (OR 3.8 (95% CI 2.5 to 5.8) and 7.4 (95% CI 4.8 to 11.2) respectively). Conclusions: Young infants contribute substantially to paediatric inpatient mortality at the first referral level, highlighting the need both for basic supportive care facilities and improved disease prevention strategies.

In February 2012, the novel respiratory syncytial virus (RSV) group A, genotype ON1, was detected in Kilifi County, coastal Kenya. ON1 is characterized by a 72-nt duplication within the highly variable G gene (encoding the immunogenic attachment surface protein). Cases were diagnosed through surveillance of pneumonia in children at the county hospital. Analysis of epidemiologic, clinical, and sequence data of RSV-A viruses detected over 5 RSV seasons (2010/2011 to 2014/2015) indicated the following: 1) replacement of previously circulating genotype GA2 ON1, 2) an abrupt expansion in the number of ON1 variants detected in the 2014/2015 epidemic, 3) recently accumulation of amino acid substitutions within the ON1 duplicated sequence, and 4) no clear evidence of altered pathogenicity relative to GA2. The study demonstrates the public health importance of molecular surveillance in defining the spread, clinical effects, and evolution of novel respiratory virus variants.

Summaryobjectives To identify factors associated with developing severe respiratory syncytial virus (RSV) pneumonia and their commonality with all-cause lower respiratory tract infection (LRTI), in order to isolate those risk factors specifically associated with RSV-LRTI and identify targets for control.methods A birth cohort of rural Kenyan children was intensively monitored for acute respiratory infection (ARI) over three RSV epidemics. RSV was diagnosed by immunofluorescence of nasal washings collected at each ARI episode. Cox regression was used to determine the relative risk of disease for a range of co-factors.results A total of 469 children provided 937 years of follow-up, and experienced 857 all-cause LRTI, 362 RSV-ARI and 92 RSV-LRTI episodes. Factors associated with RSV-LRTI, but not RSV-ARI, were severe stunting (z-score £ )2, RR 1.7 95%CI 1.1-2.8), crowding (increased number of children, RR 2.6, 1.0-6.5) and number of siblings under 6 years (RR 2.0, 1.2-3.4). Moderate and severe stunting (z-score £)1), crowding and a sibling aged over 5 years sleeping in the same room as the index child were associated with increased risk of all-cause LRTI, whereas higher educational level of the primary caretaker was associated with protection.conclusion We identify factors related to host nutritional status (stunting) and contact intensity (crowding, siblings) which are distinguishable in their association with RSV severe disease in infant and young child. These factors are broadly in common with those associated with all-cause LRTI. The results support targeted strategies for prevention.keywords respiratory syncytial virus, risk factors, disease, Kenya