■老年人群出现严重症状的风险增加,住院治疗,和COVID-19造成的生命损失。很少有研究探索65岁以上成年人的疫苗接种方案。高风险人群需要反复加强疫苗接种,因为COVID-19疫苗的效力是短暂的。我们比较了老年人第二次皮内(ID)COVID-19加强疫苗接种与第二次肌内(IM)疫苗接种的免疫原性和反应原性。
■这个单中心,开放标签,prospective,在Siriraj医院进行的队列研究纳入了年龄≥65岁的老年人,这些老年人以前曾通过ID或IM给药接受过第一次加强(第三剂)mRNA疫苗(mRNA-1273或BNT162b2).之后16-17周,参与者被分配接受相同疫苗类型和途径的第二次加强剂,作为他们的第一次加强剂。在接种后2周测量抗SARS-CoV-2受体结合域IgG和针对武汉和Omicron亚变体(BA.1、BA.2和BA.4/5)的中和抗体滴度。
■在91名注册参与者中,72.5%是女性,平均年龄为75岁。49名参与者(53.8%)接受了第二个ID增强剂,42人(46.2%)接受了第二个IM助推器。第二次助推器两周后,所有组产生的记忆性IgG抗体应答比基线高5.41~10.00倍.总的来说,与ID方案相比,在IM中观察到针对武汉和Omicron亚变体的更高抗体GMT.IDmRNA-1273在第二次加强武汉后2周诱导与IMBNT162b2相似的GMT(486.77[321.48,737.05]vs.472.63[291.24,767.01],分别为;p=0.072)。与OmicronBA.1相比,GMT更高(GMR[95%CI],1.71[1.39,2.11];p=0.023),BA.2(1.34[1.11,1.62];p=0.845),和BA.4/5(1.10[0.92,1.33];p=0.531)在第二次加强后2周,与第一次加强后2-4周相比。局部和系统性AE在第二次之后比第一次加强之后更不频繁,无论管理途径和疫苗类型。第二次加强后2周,IDmRNA-1273臂的局部AE明显高于其各自的BNT162b2臂(ID-mRNA-1273与ID-BNT162b2:p≤0.001)。
■重复部分ID疫苗接种可能是老年人群的另一种加强疫苗接种策略。
Geriatric populations are at an increased risk of severe presentations, hospitalization, and loss of life from COVID-19. Few studies have explored vaccination regimens in adults >65 years old. Repeated booster vaccination is required for high-risk populations as COVID-19 vaccine efficacy is short-lived. We compared the immunogenicity and reactogenicity of second intradermal (ID) COVID-19 booster vaccination with second intramuscular (IM) vaccination in older adults.
This single-center, open-labeled, prospective, cohort study conducted at Siriraj Hospital enrolled older adults ≥65 years old who previously received a first booster (third dose) mRNA vaccine (mRNA-1273 or BNT162b2) via ID or IM administration. Participants were allocated to receive a second booster of the same vaccine type and route as their first booster 16-17 weeks thereafter. Anti-SARS-CoV-2 receptor binding domain IgG and neutralizing antibody titers against Wuhan and Omicron subvariants (BA.1, BA.2, and BA.4/5) were measured 2 weeks after vaccination.
Of 91 enrolled participants, 72.5% were women, with a median age of 75 years. Forty-nine participants (53.8%) received a second ID booster, and 42 (46.2%) received a second IM booster. Two weeks after the second booster, all groups generated anamnestic IgG antibody responses that were 5.41- to 10.00-fold higher than at baseline. Overall, higher antibody GMTs against Wuhan and Omicron subvariants were observed in IM compared with ID regimens. ID mRNA-1273 induced similar GMTs to IM BNT162b2 2 weeks after the second booster against Wuhan (486.77 [321.48, 737.05] vs. 472.63 [291.24, 767.01], respectively; p = 0.072). Higher GMTs against Omicron BA.1 (GMR [95% CI], 1.71 [1.39, 2.11]; p = 0.023), BA.2 (1.34 [1.11, 1.62]; p = 0.845), and BA.4/5 (1.10 [0.92, 1.33]; p = 0.531) were seen in all groups at 2 weeks after the second booster compared with 2-4 weeks after the first booster. Both local and systemic AEs were less frequent after the second than after the first booster, regardless of administrative route and vaccine type. Local AEs were significantly more frequent in ID mRNA-1273 arms than their respective BNT162b2 arms 2 weeks after the second booster (ID-mRNA-1273 vs. ID-BNT162b2: p ≤ 0.001).
Repeated fractional ID vaccination may be an alternative booster vaccination strategy for geriatric populations.