Comparison of clinical diagnosis of children hospitalized for influenza A pH1N1 with age- matched controls hospitalized for seasonal H1N1 and H3N2, and with children hospitalized for seasonal influenza concurrently during the study period, respectively.

<p>Comparison of clinical diagnosis of children hospitalized for influenza A pH1N1 with age- matched controls hospitalized for seasonal H1N1 and H3N2, and with children hospitalized for seasonal influenza concurrently during the study period, respectively.</p

Comparisons of pre-existing high risk conditions of children hospitalized for influenza A pH1N1 with age- matched controls hospitalized for seasonal H1N1 and H3N2, and with children hospitalized for seasonal influenza concurrently during the study period, respectively.

<p>Comparisons of pre-existing high risk conditions of children hospitalized for influenza A pH1N1 with age- matched controls hospitalized for seasonal H1N1 and H3N2, and with children hospitalized for seasonal influenza concurrently during the study period, respectively.</p

Comparison of titers obtained with H5pp versus MN assays for two panels of paired sera.

<p>Titers (reciprocal dilution of serum that gives 50% neutralization) were determined for sera from elderly (>65 yr) recipient of H5N1 vaccine selected to include 16 with pre-vaccination MN H5N1 titer ≥20 and 10 randomly selected seronegative persons with MN titer <20 and HI <8. The post vaccination was sampled 21 days post vaccination. The graph (A) shows the correlation of antibody titers in pre- (circles) and post (square) vaccination sera obtained with the H5 MN (sanofi pasteur method) and H5pp tests for those who were MN seropositive (black markers) and seronegative (open markers) pre-vaccination. Graph (B) shows the pre- and post H5N1 vaccination H5pp antibody titers in those with (“seropositive”) and without (“seronegative”) pre-vaccine antibody. For computation, the sera with undetectable antibody titers were given the value of 10. Positivity criterion (titer≥20) is represented by dashed lines.</p

Effect of seasonal vaccination on H5 neutralizing antibody titers measured by the microneutralization (MN) and the H5pp tests in paired sera from children, adults, and elderly after vaccination with seasonal influenza vaccine and H5N1 vaccine.

a<p>Patient cohorts from Hong Kong.</p>b<p>Patient cohorts from Europe.</p>c<p>N: Number of paired samples.</p>d<p>For the computation of geometric mean titers, negative sera (titer <20) are assigned value of 10 (first dilution tested 20). Student's t-test was used to calculate p-value.</p

Comparison of H5 neutralizing antibodies tested by MN and H5pp tests for different age groups.

<p>Titers were measured from paired sera of 98 children (A, B), 20 adults (C, D) and 118 elderly (E, F) given seasonal influenza vaccination; (G, H) 42 pairs sera from adults recipient of H5N1 clinical candidate vaccines. Dashed line marks the positivity criteria (titer≥20). Each line represents a paired serum from one individual. Where more than one person has identical pre and post antibody titers, the number of persons with these overlapping results is denoted as n. The MN titers were determined at HKU using the MN-HKU method (see methods).</p