There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered. For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO–UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up. We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248–134 941) during calendar years 2020–30, largely due to measles. For years of vaccination 2020–30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52–2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249–40 241 202) to 36 410 559 deaths averted (33 515 397–39 241 799). We estimated that catch-up activities could avert 78·9% (40·4–151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037–60 223] of 25 356 [9859–75 073]). Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption. The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation. For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.

中文翻译：

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估计 2020-30 年间 112 个国家与 COVID-19 相关的免疫接种中断对健康的影响：一项建模研究

由于 COVID-19 大流行，全球免疫覆盖率有所下降。复苏已经开始，但各地情况各不相同。这种破坏导致群体免疫不足，并中断了减少疫苗可预防疾病负担的进展。到目前为止，关于覆盖范围中断对疫苗效果影响的研究很少。我们的目的是量化疫苗覆盖率中断对常规和运动免疫服务的影响，确定可以从追赶活动中特别受益的人群和地区，并确定是否可以弥补实际损失。在这项建模研究中，我们使用来自 112 个低收入和中等收入国家的疫苗影响建模联盟的建模小组来估计疫苗对 14 种病原体的效果。一组模型估计使用了 1937 年至 2021 年的疫苗覆盖率数据，针对疫苗可预防、易暴发或优先疾病的子集（即麻疹、风疹、乙型肝炎、人乳头瘤病毒 [HPV]、甲型脑膜炎和黄热病） ）检查缓解措施，以下简称恢复运行。第二组估计是根据 1937 年至 2020 年的疫苗覆盖率数据进行的，用于计算所有 14 种疫苗和疾病的效果比（即每剂避免的负担），以下简称“全面运行”。两次运行均以 2000 年 1 月 1 日至 2100 年 12 月 31 日为模型。有显着的负担；或有显着的战略疫苗接种活动。这些国家占全球疫苗可预防疾病负担的大部分。疫苗覆盖率根据世卫组织-联合国儿童基金会《国家免疫覆盖率估计》和世卫组织免疫接种库截至 2021 年（包括 2021 年）数据的历史估计提供。从 2022 年起，我们根据有关运动频率和非线性假设的指导来估计覆盖率关于将常规免疫接种恢复到中断前的程度，以及根据世卫组织 2030 年免疫议程目标和专家咨询通报的 2030 年终点。我们研究了三种主要场景：无中断、基线恢复以及基线恢复和追赶。我们估计，2020-30 日历年间，麻疹、风疹、HPV、乙型肝炎、甲型脑膜炎和黄热病疫苗接种的中断可能会导致 49 119 人额外死亡（95% 可信区间 [CrI] 17 248–134 941），由于麻疹。对于 2020-30 年所有 14 种病原体的疫苗接种，中断可能导致长期影响减少 2·66% (95% CrI 2·52–2·81)，避免 37 378 194 例死亡 (34 450 249–避免了 40 241 202) 至 36 410 559 人死亡 (33 515 397–39 241 799)。我们估计，追赶活动可以避免 2023 年至 2030 年期间 78·9% (40·4–151·4) 的超额死亡（即 25 356 人中的 18 900 人 [7037–60 223] [9859–75 073] ]）。我们的结果凸显了追赶活动时机的重要性，考虑提高受影响人群疫苗覆盖率的估计负担。我们估计，麻疹和黄热病的缓解措施对于减轻短期过度负担特别有效。此外，HPV 疫苗作为重要的宫颈癌预防工具，具有良好的长期效果，因此在中断后仍需继续开展免疫工作。疫苗影响模型联盟，由全球疫苗免疫联盟、疫苗联盟和比尔及梅琳达·盖茨基金会资助。有关摘要的阿拉伯语、中文、法语、葡萄牙语和西班牙语翻译，请参阅补充材料部分。