Sah Pratha, Vilches Thomas N, Moghadas Seyed M, Fitzpatrick Meagan C, Singer Burton H, Hotez Peter J, Galvani Alison P
Center for Infectious Disease Modeling and Analysis (CIDMA), Yale School of Public Health, New Haven, CT, USA.
Agent-Based Modelling Laboratory, York University, Toronto, Ontario M3J 1P3 Canada.
EClinicalMedicine. 2021 May;35:100865. doi: 10.1016/j.eclinm.2021.100865. Epub 2021 Apr 25.
More contagious variants of SARS-CoV-2 have emerged around the world, sparking concerns about impending surge in cases and severe outcomes. Despite the development of effective vaccines, rollout has been slow. We evaluated the impact of accelerated vaccine distribution on curbing the disease burden of novel SARS-CoV-2 variants.
We used an agent-based model of SARS-CoV-2 transmission and vaccination to simulate the spread of novel variants with S-Gene Target Failure (SGTF) in addition to the original strain. We incorporated age-specific risk and contact patterns and implemented a two-dose vaccination campaign in accord with CDC-recommended prioritization. As a base case, we projected hospitalizations and deaths at a daily vaccination rate of 1 million doses in the United States (US) and compared with accelerated campaigns in which daily doses were expanded to 1.5, 2, 2.5, or 3 million.
We found that at a vaccination rate of 1 million doses per day, an emergent SGTF variant that is 20-70% more transmissible than the original variant would become dominant within 2 to 9 weeks, accounting for as much as 99% of cases at the outbreak peak. Our results show that accelerating vaccine delivery would substantially reduce severe health outcomes. For a SGTF with 30% higher transmissibility, increasing vaccine doses from 1 to 3 million per day would avert 152,048 (95% CrI: 134,772-168,696) hospitalizations and 48,448 (95% CrI: 42,042-54,285) deaths over 300 days. Accelerated vaccination would also prevent additional COVID-19 waves that would otherwise be fuelled by waning adherence to non-pharmaceutical interventions (NPIs).
We found that the current pace of vaccine rollout is insufficient to prevent the exacerbation of the pandemic that will be attributable to the novel, more contagious SARS-CoV-2 variants. Accelerating the vaccination rate should be a public health priority for averting the expected surge in COVID-19 hospitalizations and deaths that would be associated with widespread dissemination of the SGTF variants. Our results underscore the need to bolster the production and distribution of COVID-19 vaccines, to rapidly expand vaccination priority groups and distribution sites.
新型冠状病毒（SARS-CoV-2）更具传染性的变种已在全球出现，引发了对病例即将激增和严重后果的担忧。尽管已研发出有效的疫苗，但疫苗推广速度一直很慢。我们评估了加速疫苗分发对遏制新型SARS-CoV-2变种疾病负担的影响。
我们使用基于代理的SARS-CoV-2传播和疫苗接种模型，来模拟除原始毒株外具有S基因靶标缺失（SGTF）的新型变种的传播情况。我们纳入了特定年龄的风险和接触模式，并根据美国疾病控制与预防中心（CDC）推荐的优先级开展了两剂疫苗接种活动。作为基础案例，我们预测了美国每日接种100万剂疫苗时的住院人数和死亡人数，并与加速接种活动进行比较，加速接种活动中每日接种剂量增加到150万、200万、250万或300万剂。
我们发现，在每日接种100万剂疫苗的情况下，一种比原始变种传播性高20%-70%的新出现的SGTF变种将在2至9周内成为主导，在疫情高峰时占病例的99%。我们的结果表明，加速疫苗接种将大幅减少严重健康后果。对于传播性高30%的SGTF变种，将每日疫苗接种剂量从100万剂增加到300万剂，在300天内可避免152,048例（95%可信区间：134,772-168,696）住院和48,448例（95%可信区间：42,042-54,285）死亡。加速接种还将预防原本会因对非药物干预措施（NPIs）的依从性下降而引发的额外新冠疫情浪潮。
我们发现，目前的疫苗推广速度不足以预防因新型、更具传染性的SARS-CoV-2变种导致的疫情恶化。加快疫苗接种速度应成为公共卫生的优先事项，以避免与SGTF变种广泛传播相关的预期新冠住院人数和死亡人数激增。我们的结果强调了加强新冠疫苗生产和分发、迅速扩大疫苗接种优先群体和分发地点的必要性。
