Interval between onset of illness for cases (n = 34) in outbreaks of avian influenza H5N1 infection.

<p>Panel A shows the interval between onsets of illness of index and secondary cases in outbreaks. Panel B shows the interval between onsets of illness of serial cases in outbreaks. Black denotes cases not exposed to zoonotic sources of virus and white denotes cases exposed to zoonotic sources of virus.</p

Transmission parameters for outbreaks of avian influenza H5N1 infection.

a<p>Mean number of secondary cases infected by a single index case in an exposed population of size 5, CI denotes confidence interval.</p>b<p>Mean number of zoonotic cases in an exposed population of size 5.</p>c<p>AIC_C denotes Akaike Information Criterion adjusted for small sample size. This indicates the percent probability that the model is the best amongst those considered.</p

Household size and secondary attack rate for outbreaks of avian influenza H5N1 infection.

a<p>SAR declines to 0.047 when outlier cluster is excluded.</p>b<p>SAR declines to 0.044 when outlier cluster is excluded.</p

Comparison of cases (n = 177) and healthy contacts (n = 496) in outbreaks of avian influenza H5N1 infection.

a<p>Observations  = 561, Goodness-of-fit test: P = 0.17, OR denotes odds ratio, CI denotes confidence interval. OR were adjusted for the inclusion of the three variables in the final multivariate model.</p>b<p>Data missing for two cases and 46 healthy contacts.</p>c<p>Data missing for 66 cases from the 59 outbreaks for which household data were not available.</p

Crude proportion of respiratory samples from hospitalized children testing positive for influenza by age group, study design, and population.

<p>Crude proportion of respiratory samples from hospitalized children testing positive for influenza by age group, study design, and population.</p

Pooled estimates of global pediatric influenza-associated hospitalizations per year, by age group, development status, and WHO region, among studies using PCR diagnostic testing.

<p>Pooled estimates of global pediatric influenza-associated hospitalizations per year, by age group, development status, and WHO region, among studies using PCR diagnostic testing.</p

Flow diagram for systematic review process.

<p>Flow diagram for systematic review process.</p

Characteristics of published studies and surveillance data sources about influenza-associated respiratory illness among hospitalized children, 1982–2012.

<p>Characteristics of published studies and surveillance data sources about influenza-associated respiratory illness among hospitalized children, 1982–2012.</p