Leung Daniel, Rosa Duque Jaime S, Yip Ka Man, So Hung Kwan, Wong Wilfred H S, Lau Yu Lung
Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, China.
Commun Med (Lond). 2023 Jan 5;3(1):3. doi: 10.1038/s43856-022-00233-1.
The SARS-CoV-2 Omicron BA.2 subvariant replaced BA.1 globally in early 2022, and caused an unprecedented tsunami of cases in Hong Kong, resulting in the collapse of elimination strategy. Vaccine effectiveness (VE) of BNT162b2 and CoronaVac against BA.2 is unclear.
We utilize an ecological design incorporating population-level vaccine coverage statistics and territory-wide case-level SARS-CoV-2 infection surveillance data, and investigate the VE against infection during the Omicron BA.2 wave between January 1 to April 19, 2022, in Hong Kong for children and adolescents.
We estimate VE to be 33.0% for 1 dose of BNT162b2 in children aged 5-11 and 40.8% for 2 doses of CoronaVac in children aged 3-11. We also estimate 54.9% VE for 2 doses of BNT162b2, and 55.0% VE for 2 doses of CoronaVac in adolescents aged 12-18.
Our findings support partly preserved VE against infection by variants of concerns for children and adolescents in settings with extremely low levels of prior SARS-CoV-2 circulation.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）奥密克戎BA.2亚变体于2022年初在全球范围内取代了BA.1，并在香港引发了前所未有的病例海啸，导致清零策略失败。BNT162b2疫苗和科兴疫苗针对BA.2的疫苗效力尚不清楚。
我们采用了一种生态设计，纳入了人群水平的疫苗接种覆盖率统计数据和全港病例水平的SARS-CoV-2感染监测数据，并调查了2022年1月1日至4月19日奥密克戎BA.2毒株流行期间香港儿童和青少年针对感染的疫苗效力。
我们估计，5至11岁儿童接种1剂BNT162b2疫苗的疫苗效力为33.0%，3至11岁儿童接种2剂科兴疫苗的疫苗效力为40.8%。我们还估计，12至18岁青少年接种2剂BNT162b2疫苗的疫苗效力为54.9%，接种2剂科兴疫苗的疫苗效力为55.0%。
我们的研究结果支持，在既往SARS-CoV-2极低流行水平的环境中，儿童和青少年针对关注变异株感染的疫苗效力部分得以保留。
