IntroductionSeveral vaccines for respiratory syncytial virus (RSV) are under development. Designing an effective vaccination programme for RSV requires information about the relative contribution of risk factors for severe RSV symptoms.AimTo inform preventive strategies in Europe by quantifying the contribution of key child, family and health service risk factors to the burden of RSV hospital admissions in young children.MethodsWe constructed a birth cohort study of all singleton children born in Scotland between October 2009 and September 2012 using linkage between birth registration, maternity, vaccination and hospital admission records, with follow-up until the age of 3 years. RSV-confirmed hospital admissions were defined using linkage to national laboratory surveillance data. We estimated hospital admission rates per 1,000 child years and length of stay according to each risk factor. Cox proportional hazard regression models were used to estimate adjusted hazard ratios.ResultsThere were 5,185 RSV admissions among the 169,726 children in the cohort: 48.6% of admissions occurred before the age of 6 months, and 29.6% after the age of 1 year. Children born prematurely, small for gestational age, between July and December, with chronic conditions, older siblings, mothers < 30 years old or delayed infant vaccination had a significantly increased risk of admission. Minimising the risk posed by older siblings could reduce RSV admissions by up to 34%.ConclusionFuture RSV vaccination programmes must protect children throughout early childhood. Vaccination and/or interventions to reduce transmission by older siblings could substantially reduce RSV hospital admissions.

We determined risk factors for influenza hospital admission in children aged <2 years to guide the design of paediatric vaccination programmes.We linked all singleton live births in Scotland from 2007 to 2015 to hospital administrative data and influenza laboratory reports. Cox proportional hazard models were used to identify birth and family risk factors for influenza admissions.There were 1115 influenza admissions among 424 048 children. 85.1% of admitted children were born at term and were not in a high-risk group. Presence of an older sibling was strongly associated with increased risk of influenza admission, particularly for children aged <6 months: hazard ratio for second- first-born child was 2.02 (95% CI 1.52-2.69). Maternal age<30 years and birth during autumn (age <6 months) or spring (age 6-23 months) were also associated with admission risk.Targeting vaccination programmes to high-risk children will not prevent the vast majority of influenza admissions. Parents of children aged <2 years should be advised that vaccination of older siblings will protect younger children against influenza infection. As evidence of the impact of the universal influenza vaccine programme emerges, there may be a need to reconsider universal influenza vaccination in children aged 6 months to 2 years in the UK.

Lack of preformed long-chain polyunsaturated fatty acids (LCPUFA) in infant formula has been hypothesised as contributing to cognitive differences between breast-fed and formula-fed infants. Previous systematic reviews found no cognitive differences between infants fed formula with LCPUFA and those fed formula without, but focused on early developmental measures, such as Bayley Scales of Infant Development, which are poorly differentiating and not predictive of cognitive ability in childhood. This systematic review examined the effect of randomising infants to formula supplemented with LCUFA vs unsupplemented formula on cognitive function ≥ age 2.5 years. We searched Medline, Embase the Cochrane Central Register of Controlled Trials without date limit, following a pre-published protocol according to PRISMA guidelines. We conducted random effects meta-analyses in RevMan v5.4 and followed GRADE and Cochrane Guidelines to evaluate strength of evidence and potential for bias. We included 8 trial cohorts which randomised participants between 1993 and 2004 and analyse 6 previously unpublished outcomes provided by various trialists. Age at the last available cognitive test ranged from 3.3 to 16 years. The pooled mean difference in Wechsler Preschool and Primary Scale of Intelligence-Revised from four trials in term-born children showed no benefit of LCPUFA: -0.04 points (95% confidence interval -5.94 to 5.85, 95% prediction interval -14.17 to 14.25). The pooled mean difference in Wechsler Abbreviated Scale of Intelligence score from two trials in preterm-born children also showed no benefit of LCPUFA: -7.71 (95% CI -24.63 to 9.22, 95% PI -97.80 to 82.38). Overall quality of evidence was low, due to substantial heterogeneity, low rates of follow-up, and indications of selective publication. The long-term effect of LCPUFA supplementation in term and preterm-born infants on cognition is highly uncertain and includes potential for large benefit as well as large harm. Based on our findings, LCPUFA supplementation of infant formula is not recommended until further robust evidence excludes long-term harm. Study registration PROSPERO registration numbers CRD42018105196 and CRD42018088868.

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