Fig. 5.

New admissions and seroprevalence fit of the population models from the ABC-rejection algorithm. The shaded area for new hospital admissions indicate the 95% negative binomial distribution confidence interval which were used for the likelihood evaluation of the model. The vaccination programme in Denmark was initiated in December 2020 in the older age groups, and thus the risk of hospital admission in these age groups were reduced compared to predicted during the Spring. Additionally, as a consequence of the vaccination programme initiation, seroprevalence data was not available beyond December 2020. The displayed 5% best models spans seasonality estimates of 27%-29%; and the 5%-95% quantile estimates spans seasonality magnitudes from 24%–31% (i.e. the 95% CI for seasonality).