Yamamoto Shohei, Matsuda Kouki, Maeda Kenji, Mizoue Tetsuya, Horii Kumi, Okudera Kaori, Tan Tomofumi, Oshiro Yusuke, Inamura Natsumi, Nemoto Takashi, S Takeuchi Junko, Konishi Maki, Sugiyama Haruhito, Aoyanagi Nobuyoshi, Sugiura Wataru, Ohmagari Norio
Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan.
Division of Antiviral Therapy, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima, Japan.
Open Forum Infect Dis. 2024 Sep 6;11(9):ofae519. doi: 10.1093/ofid/ofae519. eCollection 2024 Sep.
Data are limited on the protective role of the Omicron BA bivalent vaccine, previous infection, and their induced neutralizing antibodies against Omicron XBB.1.16 and EG.5.1 infection.
We conducted a nested case-control analysis among tertiary hospital staff in Tokyo who had received ≥3 doses of COVID-19 vaccines and donated blood samples in June 2023 (1 month before the Omicron XBB.1.16 and EG.5.1 wave). We identified 206 symptomatic cases between June and September 2023 and selected their controls with 1:1 propensity score matching. We examined the association of vaccination, previous infection, and preinfection live virus neutralizing antibody titers against Omicron XBB.1.16 and EG.5.1 with the risk of COVID-19 infection.
Previous infection during the Omicron BA- or XBB-dominant phase was associated with a significantly lower infection risk during the XBB.1.16 and EG.5.1-dominant phase than infection-naive status, with 70% and 100% protection, respectively, whereas Omicron BA bivalent vaccination showed no association. Preinfection neutralizing titers against XBB.1.16 and EG.5.1 were 39% (95% CI, 8%-60%) and 28% (95% CI, 8%-44%) lower in cases than matched controls. Neutralizing activity against XBB.1.16 and EG.5.1 was somewhat detectable in the sera of individuals with previous infection but barely detectable in those who were infection naive and received the Omicron bivalent vaccine.
In the era when the Omicron XBB vaccine was unavailable, the Omicron BA bivalent vaccine did not confer the neutralizing activity and protection against Omicron XBB.1.16 and EG.5.1 symptomatic infection. The previous infection afforded neutralizing titers and protection against symptomatic infection with these variants.
关于奥密克戎BA二价疫苗的保护作用、既往感染以及它们诱导产生的针对奥密克戎XBB.1.16和EG.5.1感染的中和抗体的数据有限。
我们在东京的三级医院工作人员中进行了一项巢式病例对照分析，这些工作人员已接种≥3剂新冠疫苗，并于2023年6月（奥密克戎XBB.1.16和EG.5.1毒株流行前1个月）捐献了血样。我们确定了2023年6月至9月期间的206例有症状病例，并通过1:1倾向评分匹配选择了他们的对照。我们研究了疫苗接种、既往感染以及针对奥密克戎XBB.1.16和EG.5.1的感染前活病毒中和抗体滴度与新冠病毒感染风险之间的关联。
在奥密克戎BA或XBB占主导阶段的既往感染与在XBB.1.16和EG.5.1占主导阶段的感染风险显著低于未感染状态相关，保护率分别为70%和100%，而奥密克戎BA二价疫苗接种则无关联。病例组针对XBB.1.16和EG.5.1的感染前中和滴度分别比匹配的对照组低39%（95%CI，8%-60%）和28%（95%CI，8%-44%）。既往感染个体的血清中对XBB.1.16和EG.5.1的中和活性在一定程度上可检测到，但在未感染且接种奥密克戎二价疫苗的个体中几乎检测不到。
在无法获得奥密克戎XBB疫苗的时代，奥密克戎BA二价疫苗未赋予针对奥密克戎XBB.1.16和EG.5.1有症状感染的中和活性和保护作用。既往感染可产生中和滴度并预防这些变异株的有症状感染。
