Technical note: SARS-CoV-2 variants and vaccination in Belgium (v2021-05-06)
The SIMID consortium prepared a third technical note (v2021-05-06) containing the model estimates of hospital and ICU admissions and load by a short term prediction model and a stochastic dynamic transmission model using observational data up to May 1st, 2021.
Conclusions
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The age-specific vaccination uptake and the higher transmissibility and severity of variants of concern (VOC), primarily VOC-202012/1 or lineage B.1.1.7, have caused a change in the relation between confirmed COVID-19 cases, daily number of new hospitalizations, hospital load, ICU load and number of COVID-19 related deaths (see e.g. Davies et al. 2021, Patone et al. 2021).
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The short term prediction model depicts a further decrease in new hospitalizations and ICU load, driven by the current decrease in positivity ratio and the observed mobility patterns. The model predicts between 63 and 116 new hospital admissions and between 441 and 468 patients in ICU on May 19th.
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Dynamic stochastic modelling of the underlying mechanisms informed by empirical social contact data up to April 18th, 2021, shows also decreasing trends that reach on average 100 hospital admissions and an ICU load of 500 beds by the end of May. However, these projections show large credible intervals and should be interpreted with care.
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Model scenarios assuming a shift in behavior (and transmission) after the Easter holiday (19-24 April, 2021) in line with the situation before the holidays (1-24 March, 2021) show a plateau in hospital admissions in May-June 2021.
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Model scenarios assuming also a substantial change in behavior in May 2021, show a resurgence of the hospital admissions and associated occupancy in ICU and non-ICU. This is more pronounced when this behavioural change occurs from the 1st of May, instead of from the 15th of May onwards.