Department of Pathology, Anatomy, and Laboratory Medicine, West Virginia University School of Medicine, Morgantown.
Clinical & Translational Sciences Institute, West Virginia University, Morgantown.
JAMA Netw Open. 2022 Sep 1;5(9):e2231334. doi: 10.1001/jamanetworkopen.2022.31334.
West Virginia prioritized SARS-CoV-2 vaccine delivery to nursing home facilities because of increased risk of severe illness in elderly populations. However, the persistence and protective role of antibody levels remain unclear.
To examine the persistence of humoral immunity after COVID-19 vaccination and the association of SARS-CoV-2 antibody levels and subsequent infection among nursing home residents and staff.
DESIGN, SETTING, AND PARTICIPANTS: In this cross-sectional study, blood samples were procured between September 13 and November 30, 2021, from vaccinated residents and staff at participating nursing home facilities in the state of West Virginia for measurement of SARS-CoV-2 antibody (anti-receptor binding domain [RBD] IgG). SARS-CoV-2 infection and vaccination history were documented during specimen collection and through query of the state SARS-CoV-2 surveillance system through January 16, 2022.
SARS-CoV-2 vaccination (with BNT162b2, messenger RNA-1273, or Ad26.COV2.S).
Anti-RBD IgG levels were assessed using multivariate analysis to examine associations between time since vaccination or infection, age, sex, booster doses, and vaccine type. Antibody levels from participants who became infected after specimen collection were compared with those without infection to correlate antibody levels with subsequent infection.
Among 2139 SARS-CoV-2 vaccinated residents and staff from participating West Virginia nursing facilities (median [range] age, 67 [18-103] years; 1660 [78%] female; 2045 [96%] White), anti-RBD IgG antibody levels decreased with time after vaccination or infection (mean [SE] estimated coefficient, -0.025 [0.0015]; P < .001). Multivariate regression modeling of participants with (n = 608) and without (n = 1223) a known history of SARS-CoV-2 infection demonstrated significantly higher mean (SE) antibody indexes with a third (booster) vaccination (with infection: 11.250 [1.2260]; P < .001; without infection: 8.056 [0.5333]; P < .001). Antibody levels (calculated by dividing the sample signal by the mean calibrator signal) were significantly lower among participants who later experienced breakthrough infection during the Delta surge (median, 2.3; 95% CI, 1.8-2.9) compared with those without breakthrough infection (median, 5.8; 95% CI, 5.5-6.1) (P = .002); however, no difference in absorbance indexes was observed in participants with breakthrough infections occurring after specimen collection (median, 5.9; 95% CI, 3.7-11.1) compared with those without breakthrough infection during the Omicron surge (median, 5.8; 95% CI, 5.6-6.2) (P = .70).
In this cross-sectional study, anti-RBD IgG levels decreased after vaccination or infection. Higher antibody responses were found in individuals who received a third (booster) vaccination. Although lower antibody levels were associated with breakthrough infection during the Delta surge, no significant association was found between antibody level and infection observed during the Omicron surge. The findings of this cross-sectional study suggest that among nursing home residents, COVID-19 vaccine boosters are important and updated vaccines effective against emerging SARS-CoV-2 variants are needed.
重要性：西弗吉尼亚州优先考虑向养老院提供 SARS-CoV-2 疫苗，因为老年人患重病的风险增加。然而，抗体水平的持久性和保护作用仍不清楚。
目的：研究 COVID-19 疫苗接种后体液免疫的持久性，以及养老院居民和工作人员中 SARS-CoV-2 抗体（抗受体结合域 [RBD] IgG）水平与随后感染之间的关系。
设计、地点和参与者：在这项横断面研究中，于 2021 年 9 月 13 日至 11 月 30 日从参与西弗吉尼亚州养老院设施的接种疫苗的居民和工作人员中采集血样，用于测量 SARS-CoV-2 抗体（抗受体结合域 [RBD] IgG）。在采集标本期间以及通过查询州 SARS-CoV-2 监测系统（截至 2022 年 1 月 16 日）记录了 SARS-CoV-2 感染和疫苗接种史。
暴露：SARS-CoV-2 疫苗接种（使用 BNT162b2、信使 RNA-1273 或 Ad26.COV2.S）。
主要结果和措施：使用多变量分析评估抗 RBD IgG 水平，以研究接种或感染后时间、年龄、性别、加强剂量和疫苗类型之间的关联。将标本采集后感染的参与者的抗体水平与未感染的参与者进行比较，以将抗体水平与随后的感染相关联。
结果：在来自参与西弗吉尼亚州养老院设施的 2139 名接种 SARS-CoV-2 的居民和工作人员中（中位数[范围]年龄，67[18-103]岁；1660[78%]为女性；2045[96%]为白人），抗 RBD IgG 抗体水平随接种或感染后时间的推移而下降（平均[SE]估计系数，-0.025[0.0015]；P < .001）。对已知 SARS-CoV-2 感染史（n = 608）和无感染史（n = 1223）的参与者进行多变量回归模型分析，结果显示，第三次（加强）接种疫苗的参与者的平均（SE）抗体指数显著更高（有感染：11.250[1.2260]；P < .001；无感染：8.056[0.5333]；P < .001）。在 Delta 浪涌期间经历突破性感染的参与者的抗体水平（通过将样本信号除以平均校准剂信号计算得出）显著低于未发生突破性感染的参与者（中位数，2.3；95%CI，1.8-2.9）相比（中位数，5.8；95%CI，5.5-6.1）（P = .002）；然而，在 Omicron 浪涌期间，突破性感染参与者的吸光度指数与未发生突破性感染的参与者无差异（中位数，5.9；95%CI，3.7-11.1）相比（中位数，5.8；95%CI，5.6-6.2）（P = .70）。
结论和相关性：在这项横断面研究中，接种疫苗或感染后，抗 RBD IgG 水平下降。接受第三次（加强）疫苗接种的个体产生了更高的抗体反应。尽管在 Delta 浪涌期间较低的抗体水平与突破性感染相关，但在 Omicron 浪涌期间观察到的感染与抗体水平之间未发现显著关联。这项横断面研究的结果表明，在养老院居民中，COVID-19 疫苗加强剂很重要，需要针对不断出现的 SARS-CoV-2 变异株的更新疫苗。
