Borchering Rebecca K, Mullany Luke C, Howerton Emily, Chinazzi Matteo, Smith Claire P, Qin Michelle, Reich Nicholas G, Contamin Lucie, Levander John, Kerr Jessica, Espino J, Hochheiser Harry, Lovett Kaitlin, Kinsey Matt, Tallaksen Kate, Wilson Shelby, Shin Lauren, Lemaitre Joseph C, Hulse Juan Dent, Kaminsky Joshua, Lee Elizabeth C, Davis Jessica T, Mu Kunpeng, Xiong Xinyue, Piontti Ana Pastore Y, Vespignani Alessandro, Srivastava Ajitesh, Porebski Przemyslaw, Venkatramanan Srini, Adiga Aniruddha, Lewis Bryan, Klahn Brian, Outten Joseph, Hurt Benjamin, Chen Jiangzhuo, Mortveit Henning, Wilson Amanda, Marathe Madhav, Hoops Stefan, Bhattacharya Parantapa, Machi Dustin, Chen Shi, Paul Rajib, Janies Daniel, Thill Jean-Claude, Galanti Marta, Yamana Teresa, Pei Sen, Shaman Jeffrey, Espana Guido, Cavany Sean, Moore Sean, Perkins Alex, Healy Jessica M, Slayton Rachel B, Johansson Michael A, Biggerstaff Matthew, Shea Katriona, Truelove Shaun A, Runge Michael C, Viboud Cécile, Lessler Justin
The Pennsylvania State University (PSU).
Johns Hopkins University Applied Physics Lab (JHU/APL).
medRxiv. 2022 Mar 10:2022.03.08.22271905. doi: 10.1101/2022.03.08.22271905.
SARS-CoV-2 vaccination of persons aged 12 years and older has reduced disease burden in the United States. The COVID-19 Scenario Modeling Hub convened multiple modeling teams in September 2021 to project the impact of expanding vaccine administration to children 5-11 years old on anticipated COVID-19 burden and resilience against variant strains.
Nine modeling teams contributed state- and national-level projections for weekly counts of cases, hospitalizations, and deaths in the United States for the period September 12, 2021 to March 12, 2022. Four scenarios covered all combinations of: 1) presence vs. absence of vaccination of children ages 5-11 years starting on November 1, 2021; and 2) continued dominance of the Delta variant vs. emergence of a hypothetical more transmissible variant on November 15, 2021. Individual team projections were combined using linear pooling. The effect of childhood vaccination on overall and age-specific outcomes was estimated by meta-analysis approaches.
Absent a new variant, COVID-19 cases, hospitalizations, and deaths among all ages were projected to decrease nationally through mid-March 2022. Under a set of specific assumptions, models projected that vaccination of children 5-11 years old was associated with reductions in all-age cumulative cases (7.2%, mean incidence ratio [IR] 0.928, 95% confidence interval [CI] 0.880-0.977), hospitalizations (8.7%, mean IR 0.913, 95% CI 0.834-0.992), and deaths (9.2%, mean IR 0.908, 95% CI 0.797-1.020) compared with scenarios where children were not vaccinated. This projected effect of vaccinating children 5-11 years old increased in the presence of a more transmissible variant, assuming no change in vaccine effectiveness by variant. Larger relative reductions in cumulative cases, hospitalizations, and deaths were observed for children than for the entire U.S. population. Substantial state-level variation was projected in epidemic trajectories, vaccine benefits, and variant impacts.
Results from this multi-model aggregation study suggest that, under a specific set of scenario assumptions, expanding vaccination to children 5-11 years old would provide measurable direct benefits to this age group and indirect benefits to the all-age U.S. population, including resilience to more transmissible variants.
12岁及以上人群接种严重急性呼吸综合征冠状病毒2（SARS-CoV-2）疫苗减轻了美国的疾病负担。2021年9月，新冠疫情情景建模中心召集了多个建模团队，以预测将疫苗接种扩大到5至11岁儿童对预期的新冠负担以及针对变异毒株的抵御能力的影响。
九个建模团队提供了2021年9月12日至2022年3月12日期间美国每周病例数、住院人数和死亡人数的州级和国家级预测。四种情景涵盖了以下所有组合：1）2021年11月1日起5至11岁儿童接种疫苗与否；2）2021年11月15日Delta变异株持续占主导地位与出现一种假设的传播性更强的变异株。各团队的预测通过线性合并进行整合。采用荟萃分析方法估计儿童接种疫苗对总体和特定年龄结果的影响。
在没有新变异株的情况下，预计到2022年3月中旬，全国所有年龄段的新冠病例、住院人数和死亡人数都会下降。在一组特定假设下，模型预测，与儿童未接种疫苗的情景相比，5至11岁儿童接种疫苗可使全年龄段累计病例数减少（7.2%，平均发病率比[IR]为0.928，95%置信区间[CI]为0.880至0.977）、住院人数减少（8.7%，平均IR为0.913，95%CI为0.834至0.992）、死亡人数减少（9.2%，平均IR为0.908，95%CI为0.797至1.020）。假设变异株对疫苗效力无影响，在出现传播性更强的变异株的情况下，5至11岁儿童接种疫苗的预计效果会增加。与美国全人群相比，儿童的累计病例数、住院人数和死亡人数的相对减少幅度更大。预计疫情轨迹、疫苗益处和变异株影响在州级层面存在很大差异。
这项多模型汇总研究的结果表明，在一组特定的情景假设下，将疫苗接种扩大到5至11岁儿童将为该年龄组带来可衡量的直接益处，并为美国全人群带来间接益处，包括对传播性更强的变异株的抵御能力。
