Infection control measures are effective for nosocomial COVID-19 prevention but bear substantial health-economic costs, motivating their “de-escalation” in settings at low risk of SARS-CoV-2 transmission. Yet consequences of de-escalation are difficult to predict, particularly in light of novel variants and heterogeneous population immunity. To estimate how infection control measure de-escalation influences nosocomial COVID-19 risk. An individual-based transmission model was used to simulate SARS-CoV-2 outbreaks and control measure de-escalation in a French long-term care hospital with multi-modal control measures in place (testing and isolation, universal masking, single-occupant rooms). Estimates of COVID-19 case fatality rates (CFRs) from reported outbreaks were used to quantify excess COVID-19 mortality due to de-escalation. In a population fully susceptible to infection, de-escalating both universal masking and single rooms resulted in hospital-wide outbreaks of 114 (95% CI: 103–125) excess infections, compared with five (three to seven) excess infections when de-escalating only universal masking or 15 (11–18) when de-escalating only single rooms. When de-escalating both measures and applying CFRs from the first wave of COVID-19, excess patient mortality ranged from 1.57 (1.41–1.71) to 9.66 (8.73–10.57) excess deaths/1000 patient-days. By contrast, when applying CFRs from subsequent pandemic waves and assuming susceptibility to infection among 40–60% of individuals, excess mortality ranged from 0 (0–0) to 0.92 (0.77–1.07) excess deaths/1000 patient-days. The de-escalation of bundled COVID-19 control measures may facilitate widespread nosocomial SARS-CoV-2 transmission. However, excess mortality is probably limited in populations at least moderately immune to infection and given CFRs resembling those estimated during the ‘post-vaccine’ era.

中文翻译：

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预测 COVID-19 控制措施降级对院内传播和死亡率的影响：法国一家康复医院的模型研究

感染控制措施对于院内 COVID-19 预防有效，但会带来巨大的健康经济成本，因此在 SARS-CoV-2 传播风险较低的环境中，感染控制措施会“降级”。然而，降级的后果很难预测，特别是考虑到新的变异和异质的群体免疫。评估感染控制措施降级如何影响院内 COVID-19 风险。法国一家长期护理医院使用基于个体的传播模型来模拟 SARS-CoV-2 爆发并控制措施降级，并采取了多模式控制措施（检测和隔离、通用口罩、单人病房） ）。根据报告的疫情对 COVID-19 病死率 (CFR) 的估计被用来量化因降级而导致的过量 COVID-19 死亡率。在完全易受感染的人群中，降低普遍口罩和单间隔离措施导致全院范围内暴发 114 例（95% CI：103-125）例过量感染，而当取消通用口罩和单人病房时，则发生 5 例（3 至 7 例）过量感染。仅升级通用屏蔽或仅升级单个房间时升级 15 (11–18)。当降低这两项措施并应用第一波 COVID-19 的病死率时，超额患者死亡率范围为 1.57 (1.41–1.71) 至 9.66 (8.73–10.57) 超额死亡/1000 个患者日。相比之下，当应用随后大流行浪潮的病死率并假设 40-60% 的个体对感染易感时，超额死亡率范围为 0 (0-0) 至 0.92 (0.77-1.07) 超额死亡/1000 个患者日。捆绑式 COVID-19 控制措施的降级可能会促进 SARS-CoV-2 的广泛院内传播。然而，在至少对感染具有中等免疫能力且病死率类似于“后疫苗”时代估计的人群中，过高的死亡率可能是有限的。