COVID-19 Delta Wave Caused Early Overburden of Hospital Capacity in the Bulgarian Healthcare System in 2021

Abstract

We develop and apply our methodology to estimate the overburdening of hospitals in Bulgaria during the upcoming delta surge. We base our estimations on an exponential risk model from the UK. Still, the methodology is generally applicable to all risk models, depending on age. Our hypothesis is that during the delta wave in Bulgaria, the system experienced a burden from late August due to decreased capacity. This will explain most of the excess mortality during the wave. We estimate the number of people from the active cases in need of hospitalization and intensive care.

Keywords: COVID-19; excess mortality; health system capacity; hospitalization risk.

Figure 1

Probability density function of new cases by age for total cases up to 3 September 2021.

Figure 2

Distribution of the share of hospitalization from the total cases up to 3 September 2021 $f_h\left(t\right)$g.

Figure 3

Comparison of 7, 14, and 21-days moving averages for r₆₀₊.

Figure 4

Model for (6) with hospitalizations for the whole period.

Figure 5

Fitted model (9) for hospitalizations.

Figure 6

Model for the number of hospitalizations (11).

Figure 7

Fitted model (9) for hospitalizations.

Figure 8

Model for the number of ICU beds (11). NOTE: Hospitalizations = all currently hospitalized patients, not daily new hospitalizations. The same is for ICU beds. All calculations here are for 21-day moving averages.

Figure 9

Deviation from the model for hospitalizations from 4 to 21 September 2021.

Figure 10

Deviation from a model for ICU in the period of 4 to 21 September 2021.

Figure 11

Discrepancy between model and actual hospitalizations.

Figure 12

Discrepancy between model and actual ICU patients.