The burden of influenza in England by age and clinical risk group: A statistical analysis to inform vaccine policy

• Published in: The Journal of infection Vol. 68; no. 4; pp. 363 - 371
• Main Authors: Cromer, Deborah, van Hoek, Albert Jan, Jit, Mark, Edmunds, W. John, Fleming, Douglas, Miller, Elizabeth
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.04.2014; Elsevier
• Subjects: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Biological and medical sciences; Child; Child, Preschool; Disease burden; England - epidemiology; Female; General aspects; Health Policy; Human viral diseases; Humans; Infant; Infant, Newborn; Infectious Disease; Infectious diseases; Influenza; Influenza Vaccines - administration & dosage; Influenza, Human - epidemiology; Influenza, Human - mortality; Influenza, Human - prevention & control; Male; Medical sciences; Middle Aged; Modelling; Policy; Prevalence; Regression; Risk Factors; Survival Analysis; Vaccination; Viral diseases; Viral diseases of the respiratory system and ent viral diseases; Young Adult; England; United Kingdom; Great Britain; Europe; British Isles, England; Policy; Regression; Modelling; Disease burden; Influenza; Vaccination; Infection; Prevention; Immunoprophylaxis; Statistical analysis; Viral disease; Vaccine; Risk analysis; Age
• ISSN: 0163-4453; 1532-2742; 1532-2742
• DOI: 10.1016/j.jinf.2013.11.013

To assess the burden of influenza by age and clinical status and use this to inform evaluations of the age and risk-based influenza vaccination policy in the United Kingdom. Weekly laboratory reports for influenza and 7 other respiratory pathogens were extracted from the national database and used in a regression model to estimate the proportion of acute respiratory illness outcomes attributable to each pathogen. Influenza accounted for ∼10% of the attributed respiratory admissions and deaths in hospital. Healthy children under five had the highest influenza admission rate (1.9/1000). The presence of co-morbidities increased the admission rate by 5.7 fold for 5–14 year olds (from 0.1 to 0.56/1000), the relative risk declining to 1.8 fold in 65+ year olds (from 0.46 to 0.84/1000). The majority (72%) of influenza-attributable deaths in hospital occurred in 65+ year olds with co-morbidities. Mortality in children under 15 years was low with around 12 influenza-attributable deaths in hospital per year in England; the case fatality rate was substantially higher in risk than non-risk children. Infants under 6 months had the highest consultation and admission rates, around 70/1000 and 3/1000 respectively. Additional strategies are needed to reduce the remaining morbidity and mortality in the high-risk and elderly populations, and to protect healthy children currently not offered the benefits of vaccination.