Burden of paediatric influenza in Western Europe: a systematic review

Abstract

Background: Influenza illness in children causes significant clinical and economic burden. Although some European countries have adopted influenza immunisation policies for healthy children, the debate about paediatric influenza vaccination in most countries of the European Union is ongoing. Our aim was to summarise influenza burden (in terms of health outcomes and economic burden) in children in Western Europe via a systematic literature review.

Methods: We conducted a systematic literature search of PubMed, EMBASE, and the Cochrane Library (1970-April 2011) and extracted data on influenza burden in children (defined as aged ≤ 18 years) from 50 publications (13 reporting laboratory-confirmed influenza; 37 reporting influenza-like illness).

Results: Children with laboratory-confirmed influenza experienced hospitalisations (0.3%-20%), medical visits (1.7-2.8 visits per case), antibiotic prescriptions (7%-55%), and antipyretic or other medications for symptomatic relief (76%-99%); young children and those with severe illness had the highest rates of health care use. Influenza in children also led to absenteeism from day care, school, or work for the children, their siblings, and their parents. Average (mean or median) length of absence from school or day care associated with confirmed influenza ranged from 2.8 to 12.0 days for the children, from 1.3 to 6.0 days for their siblings, and from 1.3 to 6.3 days for their parents. Influenza negatively affected health-related quality of life in children with asthma, including symptoms and activities; this negative effect was smaller in vaccinated children than in non-vaccinated children.

Conclusions: Influenza burden in children is substantial and has a significant direct impact on the ill children and an indirect impact on their siblings and parents. The identified evidence regarding the burden of influenza may help inform both influenza antiviral use in children and paediatric immunisation policies in European countries.

Figure 1

PRISMA flow diagram of literature review for two searches: March 2009 review and April 2011 update. ILI = influenza-like illness; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-analyses.

Figure 2

Incidence of complications in children with laboratory-confirmed influenza. ED = emergency department; GI = gastrointestinal. Notes: Confidence intervals were not presented for any of these values within any of the source articles. We calculated the rate of acute otitis media for the placebo group from the Heinonen et al. [42] article as follows: (6 [the number of patients with acute otitis media at baseline] + 19 [the number of the number of patients with new episodes of acute otitis media during the study]) ÷ 61 [the total number of patients in the placebo group] = 40.9%.

Figure 3

Hospitalisations, antibiotic use, and antipyretic or symptomatic treatment use by children with culture-confirmed influenza. ED = emergency department. Notes: Each point represents a percentage value reported in one of the identified studies. Confidence intervals were not presented for any of these values within any of the source articles.

Figure 4

Length of hospital stay and number of medical visits by children with culture-confirmed influenza. ED = emergency department. * The mean number of medical visits = number of reported additional medical visits + initial 1 primary care or ED visit. ^† Length of stay in the ED, rather than in the hospital. Notes: Each point represents a mean or median value from one of the identified studies: ♦ = mean value; ▪ = median value. Effect sizes around each point represent standard deviation if value is a mean, range if value is a median.

Figure 5

Children’s absence from day care or school and parents’ absence from work associated with paediatric influenza. ED = emergency department. * Interquartile range. ^† This is the number of children with confirmed influenza in this article, so the value is the same for the row showing the whole parent population, the mothers only, and the fathers only. The article does not provide the number of mothers and the number of fathers. Notes: Each point represents a mean or median value from one of the identified studies: ♦ = mean value; ▪ = median value. Effect sizes around each point represent standard deviation if the value is a mean; range represents minimum-maximum range if the value is a median.