Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
Lancet Infect Dis. 2021 Apr;21(4):482-492. doi: 10.1016/S1473-3099(20)30984-1. Epub 2020 Dec 24.
A second wave of COVID-19 cases in autumn, 2020, in England led to localised, tiered restrictions (so-called alert levels) and, subsequently, a second national lockdown. We examined the impact of these tiered restrictions, and alternatives for lockdown stringency, timing, and duration, on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and hospital admissions and deaths from COVID-19.
We fit an age-structured mathematical model of SARS-CoV-2 transmission to data on hospital admissions and hospital bed occupancy (ISARIC4C/COVID-19 Clinical Information Network, National Health Service [NHS] England), seroprevalence (Office for National Statistics, UK Biobank, REACT-2 study), virology (REACT-1 study), and deaths (Public Health England) across the seven NHS England regions from March 1, to Oct 13, 2020. We analysed mobility (Google Community Mobility) and social contact (CoMix study) data to estimate the effect of tiered restrictions implemented in England, and of lockdowns implemented in Northern Ireland and Wales, in October, 2020, and projected epidemiological scenarios for England up to March 31, 2021.
We estimated a reduction in the effective reproduction number (R) of 2% (95% credible interval [CrI] 0-4) for tier 2, 10% (6-14) for tier 3, 35% (30-41) for a Northern Ireland-stringency lockdown with schools closed, and 44% (37-49) for a Wales-stringency lockdown with schools closed. From Oct 1, 2020, to March 31, 2021, a projected COVID-19 epidemic without tiered restrictions or lockdown results in 280 000 (95% projection interval 274 000-287 000) hospital admissions and 58 500 (55 800-61 100) deaths. Tiered restrictions would reduce hospital admissions to 238 000 (231 000-245 000) and deaths to 48 600 (46 400-50 700). From Nov 5, 2020, a 4-week Wales-type lockdown with schools remaining open-similar to the lockdown measures announced in England in November, 2020-was projected to further reduce hospital admissions to 186 000 (179 000-193 000) and deaths to 36 800 (34 900-38 800). Closing schools was projected to further reduce hospital admissions to 157 000 (152 000-163 000) and deaths to 30 300 (29 000-31 900). A projected lockdown of greater than 4 weeks would reduce deaths but would bring diminishing returns in reducing peak pressure on hospital services. An earlier lockdown would have reduced deaths and hospitalisations in the short term, but would lead to a faster resurgence in cases after January, 2021. In a post-hoc analysis, we estimated that the second lockdown in England (Nov 5-Dec 2) reduced R by 22% (95% CrI 15-29), rather than the 32% (25-39) reduction estimated for a Wales-stringency lockdown with schools open.
Lockdown measures outperform less stringent restrictions in reducing cumulative deaths. We projected that the lockdown policy announced to commence in England on Nov 5, with a similar stringency to the lockdown adopted in Wales, would reduce pressure on the health service and would be well timed to suppress deaths over the winter period, while allowing schools to remain open. Following completion of the analysis, we analysed new data from November, 2020, and found that despite similarities in policy, the second lockdown in England had a smaller impact on behaviour than did the second lockdown in Wales, resulting in more deaths and hospitalisations than we originally projected when focusing on a Wales-stringency scenario for the lockdown.
Horizon 2020, UK Medical Research Council, and the National Institute for Health Research.
2020 年秋季，英格兰出现第二波 COVID-19 病例，导致实施了局部、分层限制措施（即所谓的警戒级别），随后又实施了全国第二次封锁。我们研究了这些分层限制措施，以及封锁严格程度、时间和持续时间的替代方案对严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）传播以及 COVID-19 住院和死亡的影响。
我们拟合了一个年龄结构的 SARS-CoV-2 传播数学模型，该模型基于医院入院和医院床位占用情况（ISARIC4C/COVID-19 临床信息网络，英国国民保健署 [NHS] 英格兰）、血清阳性率（英国国家统计局、英国生物银行、REACT-2 研究）、病毒学（REACT-1 研究）和死亡情况（英国公共卫生部）的数据，这些数据来自英格兰的七个 NHS 英格兰地区，时间从 2020 年 3 月 1 日至 10 月 13 日。我们分析了移动性（谷歌社区流动性）和社交接触（CoMix 研究）数据，以估计英格兰在 2020 年 10 月实施的分层限制措施以及北爱尔兰和威尔士实施的封锁措施的效果，并对英格兰截至 2021 年 3 月 31 日的流行病学情景进行了预测。
我们估计，第 2 级限制措施将有效繁殖数（R）降低 2%（95%可信区间[CrI] 0-4），第 3 级限制措施降低 10%（6-14），北爱尔兰严格封锁且关闭学校将降低 35%（30-41），威尔士严格封锁且关闭学校将降低 44%（37-49）。从 2020 年 10 月 1 日至 2021 年 3 月 31 日，如果没有分层限制或封锁措施，预计 COVID-19 疫情将导致 28 万（95%预测区间为 27.4 万至 28.7 万）人住院和 5850 人死亡（5580 人至 6110 人）。分层限制措施将使住院人数减少到 23.8 万（23.1 万至 24.5 万），死亡人数减少到 4.86 万（4.64 万至 5.07 万）。从 2020 年 11 月 5 日起，实施类似于 2020 年 11 月在英格兰宣布的封锁措施的为期 4 周的威尔士式封锁，预计将进一步使住院人数减少到 18.6 万（17.9 万至 19.3 万），死亡人数减少到 3.68 万（3.49 万至 3.88 万）。关闭学校预计将进一步使住院人数减少到 15.7 万（15.2 万至 16.3 万），死亡人数减少到 3 万（2.9 万至 3.1 万）。封锁时间超过 4 周将减少死亡人数，但会使医院服务压力的减少效果逐渐减弱。更早的封锁将在短期内减少死亡和住院人数，但会导致 2021 年 1 月后病例迅速反弹。在事后分析中，我们估计英格兰的第二次封锁（11 月 5 日至 12 月 2 日）将 R 降低了 22%（15-29），而不是像威尔士严格封锁且关闭学校那样将 R 降低 32%（25-39）。
封锁措施在减少累计死亡人数方面优于较不严格的限制措施。我们预测，英格兰将于 2020 年 11 月 5 日开始实施的封锁政策，其严格程度与威尔士的封锁政策类似，将减轻医疗服务的压力，并将有助于在冬季期间抑制死亡人数，同时允许学校继续开放。在完成分析后，我们分析了 2020 年 11 月的新数据，发现尽管政策相似，但与威尔士的第二次封锁相比，英格兰的第二次封锁对行为的影响较小，导致死亡人数和住院人数比我们最初专注于威尔士式封锁方案时预计的要多。
Horizon 2020、英国医学研究理事会和英国国家健康研究所。
