Impact of vaccine coverage and disruption to health services on COVID-19 in Ukraine | Scientific Reports – Nature.com

Figure1 shows the modelled epidemic around the time of the start of the war in early 2022 fitted to observed data to estimate the reduction in population contacts. In the base case scenario where masks are 60% effective, the best fit to data shows a reduction in contacts of 33% in the first period and 47% to 70% in the second period (Fig.1). Otherwise, in the case of masks being effective at 40%, the best fit resulted in a reduction in contacts of 40% in the first period and 53% to 73% in the second period.

Model fit to clinical case notification data (COVID-19 incidence notification data) between 6 January 2022 and 25 February 2022, with masks 60% effective. The vertical lines represent the dates of policy changes. 6 January is the start of the Omicron wave; 617 January is the first pre-war period with the implemented restrictions policy17,18; 1825 January is the second pre-war period where the reduction in contacts increases with the additional policy of closure of public transports and enforced mask use in all public spaces17,18; 25 February represent the start of the war, where vaccine rollout and contact tracing stops.

The modelled incidence of deaths in the same period, using reported rates from European and US studies, of 0.3%, 0.08%, and 0.07% in unvaccinated, vaccinated with two and three doses respectively (Fig.2 green line), is much lower than rates reported in Ukraine (Fig.2 blue line). Multiplying those numbers by 5 times, produces a much better fit (Fig.2 red line), suggesting an under report of case numbers or higher death rates for Ukraine compared to the ones estimated in EU and the US used.

Modelled deaths (green line), multiplied by 5 (red line), and death notification data (blue line) between 6 January 2022 and 25 February 2022.

The results of sensitivity analysis on mask use, based on the last reported vaccination rates (39.3% of the 15+age group with two doses and 6.3% of the 60+with 3 doses), are shown in Figs.3 and 4. The epidemic forecast is shown in Fig.3, with hospitalization and ICU daily bed requirements in Fig.4. In each scenario, the epidemic peak was expected to be at the start of April 2022.

Number of daily new cases (incidence), cumulative cases, and cumulative deaths in the scenario with 39.3% of the 15+age group with two doses and 6.3% of the 60+with 3 doses, varying mask use coverage (0%, 50%, 80%) with 60% effectiveness, from 6 January to 14 April 2022.

Hospitalization (H) and ICU beds used over time, keeping the last vaccination coverage notified (39.3% of the 15+age group with two doses and 6.3% of the 60+with 3 doses) and varying mask use coverage (0%, 50%, 80%), from 6 January to 5 June 2022.

The outbreak peaks at about 3.7, 2.3, and 1.4 million cases, with a total of almost 90%, 80%, and 70% of the population being infected at the end of the outbreak, with 0%, 50%, and 80% of the population using masks, respectively (Fig.3). Figure4 shows that the maximum number of daily hospital beds required at the peak is estimated to be about 140, 103, and 69 thousand in scenarios of varying mask use, with a total of almost 300,000 beds available in Ukraine before the war started. The number of daily ICU beds required at the peak is estimated to be about 21, 15, and 10 thousand with 0%, 50%, and 80% mask use.

The results of the sensitivity analysis on vaccination coverage are shown in Figs.5 and 6. Figure5 shows the epidemic forecast and Fig.6, the hospitalization and ICU daily bed requirement with mask use at 50% and vaccination rates increased from 39.3% to 60% and 80%.

Case incidence, cumulative cases, and deaths in the scenario with 50% of the population using masks and varying the vaccination coverage, for 2 doses (v2) and three doses (v3), from 6 January to 16 April 2022.

Hospitalization (H) and ICU beds used over time, with 50% of the population using masks and varying the vaccination coverage for two (v2) and three doses (v3), from 6 January to 5 June 2022.

The outbreak peaks at about 2.3, 2.1, and 1.8 million cases, with a total of about 80%, 76%, and 74% of the population being infected at the end of the outbreak, at the three different vaccination scenarios (Fig.5). The maximum number of hospital beds required at the peak is estimated to be about 103, 80, and 56 thousand in each scenario, while requirements for ICU beds have been estimated to be about 15, 11, and 7 thousand (Fig.6).

From the base case scenario, the model shows increasing mask-wearing from 50% (base-case) to 80% could result in a 17% reduction in cases (from a total of 33,432,800 at 50% to 28,006,300 at 80%) and a 30% reduction in deaths (from 56,028 to 39,241). If vaccine coverage is increased from 39.3% and 6.3% with two and three doses respectively (base-case) to 60% of people aged 15+with two doses and 9.6% of people aged 60+with three doses, the reduction in cases and deaths could have been 3% (from 33,432,800 to 32,365,700) and 28% (from 56,028 to 39,867) respectively. However, when comparing the results of increasing mask use at 80% with the scenario where 80% and 12.8% of the population are vaccinated with two and three doses respectively, we found that high mask use results in a lower cumulative total number of cases (about 28 million) compared with high two doses vaccination coverage (about 31 million), but a higher number of total death (about 38,000 against 23,000). When testing if results were consistent in the case of only poor-quality masks (40% instead of 60% effectiveness) being available, we found that increasing mask use from 50% to 80% could have reduced cases and deaths by 6.1% (from 35,246,400 at 50% to 33,070,800 at 80% mask use) and 11.3% respectively (from 65,758 to 58,335). If vaccine coverage was increased to 60% with two doses and 9.6% of people aged 60+with three doses, the reduction in cases and deaths could have been respectively 2.3% (from 35,246,400 to 34,443,600) and 25.6% (from 65,758 to 48,781).

Continued here:

Impact of vaccine coverage and disruption to health services on COVID-19 in Ukraine | Scientific Reports - Nature.com