Background

The COVID-19 pandemic and efforts to reduce SARS-CoV-2 transmission substantially affected health services worldwide. To better understand the impact of the pandemic on childhood routine immunisation, we estimated disruptions in vaccine coverage associated with the pandemic in 2020, globally and by Global Burden of Disease (GBD) super-region.

Methods

For this analysis we used a two-step hierarchical random spline modelling approach to estimate global and regional disruptions to routine immunisation using administrative data and reports from electronic immunisation systems, with mobility data as a model input. Paired with estimates of vaccine coverage expected in the absence of COVID-19, which were derived from vaccine coverage models from GBD 2020, Release 1 (GBD 2020 R1), we estimated the number of children who missed routinely delivered doses of the third-dose diphtheria-tetanus-pertussis (DTP3) vaccine and first-dose measles-containing vaccine (MCV1) in 2020.

Findings

Globally, in 2020, estimated vaccine coverage was 76·7% (95% uncertainty interval 74·3–78·6) for DTP3 and 78·9% (74·8–81·9) for MCV1, representing relative reductions of 7·7% (6·0–10·1) for DTP3 and 7·9% (5·2–11·7) for MCV1, compared to expected doses delivered in the absence of the COVID-19 pandemic. From January to December, 2020, we estimated that 30·0 million (27·6–33·1) children missed doses of DTP3 and 27·2 million (23·4–32·5) children missed MCV1 doses. Compared to expected gaps in coverage for eligible children in 2020, these estimates represented an additional 8·5 million (6·5–11·6) children not routinely vaccinated with DTP3 and an additional 8·9 million (5·7–13·7) children not routinely vaccinated with MCV1 attributable to the COVID-19 pandemic. Globally, monthly disruptions were highest in April, 2020, across all GBD super-regions, with 4·6 million (4·0–5·4) children missing doses of DTP3 and 4·4 million (3·7–5·2) children missing doses of MCV1. Every GBD super-region saw reductions in vaccine coverage in March and April, with the most severe annual impacts in north Africa and the Middle East, south Asia, and Latin America and the Caribbean. We estimated the lowest annual reductions in vaccine delivery in sub-Saharan Africa, where disruptions remained minimal throughout the year. For some super-regions, including southeast Asia, east Asia, and Oceania for both DTP3 and MCV1, the high-income super-region for DTP3, and south Asia for MCV1, estimates suggest that monthly doses were delivered at or above expected levels during the second half of 2020.

Interpretation

Routine immunisation services faced stark challenges in 2020, with the COVID-19 pandemic causing the most widespread and largest global disruption in recent history. Although the latest coverage trajectories point towards recovery in some regions, a combination of lagging catch-up immunisation services, continued SARS-CoV-2 transmission, and persistent gaps in vaccine coverage before the pandemic still left millions of children under-vaccinated or unvaccinated against preventable diseases at the end of 2020, and these gaps are likely to extend throughout 2021. Strengthening routine immunisation data systems and efforts to target resources and outreach will be essential to minimise the risk of vaccine-preventable disease outbreaks, reach children who missed routine vaccine doses during the pandemic, and accelerate progress towards higher and more equitable vaccination coverage over the next decade.

Funding

Bill & Melinda Gates Foundation.

中文翻译：

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估计 2020 年 COVID-19 大流行期间常规儿童疫苗覆盖率的全球和区域中断：一项建模研究

背景

COVID-19 大流行和减少 SARS-CoV-2 传播的努力极大地影响了全世界的卫生服务。为了更好地了解大流行对儿童常规免疫接种的影响，我们估计了 2020 年全球和全球疾病负担 (GBD) 超级区域与大流行相关的疫苗覆盖率中断。

方法

对于这项分析，我们使用两步分层随机样条建模方法，使用来自电子免疫系统的管理数据和报告，以流动性数据作为模型输入，估计对常规免疫的全球和区域中断。结合根据 GBD 2020 第 1 版 (GBD 2020 R1) 的疫苗覆盖率模型得出的在没有 COVID-19 的情况下预期的疫苗覆盖率估计值，我们估计了错过第三剂常规接种剂量的儿童人数2020 年白喉-破伤风-百日咳 (DTP3) 疫苗和首剂含麻疹疫苗 (MCV1)。

发现

在全球范围内，2020 年，DTP3 和 MCV1 的估计疫苗覆盖率分别为 76·7%（95% 不确定区间 74·3–78·6）和 78·9%（74·8-81·9），相对减少了 7与在没有 COVID-19 大流行的情况下提供的预期剂量相比，DTP3 为 7% (6·0–10·1)，MCV1 为 7·9% (5·2–11·7)。从 2020 年 1 月到 12 月，我们估计有 30·00 万（27·6-33·1）个儿童错过了 DTP3 剂量，27·200 万（23·4-32·5）个儿童错过了 MCV1 剂量。与 2020 年符合条件的儿童覆盖面的预期差距相比，这些估计代表了另外 8·50 万（6·5-11·6）名未常规接种 DTP3 的儿童和另外 8·90 万（5·7-13·6）名儿童7) 由于 COVID-19 大流行而未常规接种 MCV1 的儿童。在全球范围内，2020 年 4 月，GBD 的所有超级区域的月度中断率最高，4·600 万（4·0-5·4）个儿童缺少 DTP3 剂量，4·400 万（3·7-5·2）个儿童缺少 MCV1 剂量。GBD 的每个超级区域在 3 月和 4 月都出现了疫苗覆盖率下降的情况，其中北非和中东、南亚以及拉丁美洲和加勒比地区的年度影响最为严重。我们估计撒哈拉以南非洲地区疫苗交付的年度减少最少，那里全年的中断情况仍然很小。对于一些超级区域，包括东南亚、东亚和大洋洲的 DTP3 和 MCV1，DTP3 的高收入超级区域和 MCV1 的南亚，估计表明在2020 年下半年。GBD 的每个超级区域在 3 月和 4 月都出现了疫苗覆盖率下降的情况，其中北非和中东、南亚以及拉丁美洲和加勒比地区的年度影响最为严重。我们估计撒哈拉以南非洲地区疫苗交付的年度减少最少，那里全年的中断情况仍然很小。对于一些超级区域，包括东南亚、东亚和大洋洲的 DTP3 和 MCV1，DTP3 的高收入超级区域和 MCV1 的南亚，估计表明在2020 年下半年。GBD 的每个超级区域在 3 月和 4 月都出现了疫苗覆盖率下降的情况，其中北非和中东、南亚以及拉丁美洲和加勒比地区的年度影响最为严重。我们估计撒哈拉以南非洲地区疫苗交付的年度减少最少，那里全年的中断情况仍然很小。对于一些超级区域，包括东南亚、东亚和大洋洲的 DTP3 和 MCV1，DTP3 的高收入超级区域和 MCV1 的南亚，估计表明在2020 年下半年。我们估计撒哈拉以南非洲地区疫苗交付的年度减少最少，那里全年的中断情况仍然很小。对于一些超级区域，包括东南亚、东亚和大洋洲的 DTP3 和 MCV1，DTP3 的高收入超级区域和 MCV1 的南亚，估计表明在2020 年下半年。我们估计撒哈拉以南非洲地区疫苗交付的年度减少最少，那里全年的中断情况仍然很小。对于一些超级区域，包括东南亚、东亚和大洋洲的 DTP3 和 MCV1，DTP3 的高收入超级区域和 MCV1 的南亚，估计表明在2020 年下半年。

解释

常规免疫服务在 2020 年面临严峻挑战，COVID-19 大流行造成了近代史上最广泛和最大的全球破坏。尽管最新的覆盖轨迹表明某些地区正在复苏，但由于补种免疫服务滞后、SARS-CoV-2 持续传播以及大流行前疫苗覆盖率的持续差距，仍然导致数百万儿童接种疫苗不足或未接种疫苗到 2020 年底可预防的疾病，而这些差距可能会延续到 2021 年。加强常规免疫数据系统以及有针对性的资源和外展工作对于最大程度地降低疫苗可预防疾病爆发的风险至关重要，覆盖错过常规疫苗的儿童大流行期间的剂量，

资金

比尔和梅琳达盖茨基金会。