Figure 1.
Prepandemic seroprevalence and the epidemic curve of pdmH1N1 in Hong Kong.
A Age-stratified pre-pandemic MN titer distributions which were estimated from serum samples collected in June and early-July 2009. For samples collected after July 2009, we only tested whether they were MN1∶20 and MN1:40 seropositive because of logistical constraints. B Epidemic curves of pdmH1N1 in Hong Kong and Shenzhen. Estimated weekly numbers of lab-confirmed cases in Shenzhen were extracted from [38].
Figure 2.
Age-specific ΔS40/ΔS20 during the first wave of pdmH1N1 in Hong Kong.
ΔS40 and ΔS20 at each cross-section were estimated using the method described in our previous work [11]. If ISP20 and ISP40 (among all pdmH1N1 infections) were the same as the proportions of clinical cases that became MN1:20 and MN1∶40 seropositive (i.e. around 100% and 90%, respectively [23], [24]), ΔS40/ΔS20 should have remained close to 0.9–1 (the horizontal dashed line) throughout the first wave, which was not the case in reality as shown here.
Figure 3.
Posterior distributions of parameter estimates.
Different colors correspond to different POLYMOD contact matrices. A Age-dependent parameters including IARs (first column), ISP40 (second), and age-specific susceptibility (third). B Other parameters including R(0), Tg, ISP20, reduction in within-age-group mixing due to school closure (π0, π1, π2), seed size, and scaling factor for FOI from Shenzhen (εSZ).
Figure 4.
Comparison of the data and the fitted model.
The hospitalization and serial cross-sectional seroprevalence data are shown in blue (vertical bars indicate 95% confidence intervals). Posterior intervals of hospitalizations and seroprevalence in the fitted model are shown as heat shades in which darker colors represent higher probability densities (i.e. highest density in red and zero density in white).
Table 1.
Model parameters and their posterior statistics.