Table 4. Multivariable odds ratios for a SARS-CoV-2 NAAT-positive test result in participants in study of SARS-CoV-2 spike antibody levels, by phase of predominant circulating viral strain, Dominican Republic, March 2021–August 2022*.
S antibody titer quartile | OR (95% CI)† |
||||
---|---|---|---|---|---|
Total, N = 2,300 | Pre-Delta, n = 646 | Delta, n = 764 | Omicron (BA.1), n = 464 | Omicron (BA.2/4/5), n = 426 | |
Q1 | Referent | Referent | Referent | Referent | Referent |
Q2 | 0.55 (0.40–0.74)§ | 0.25 (0.14–0.44)§ | 0.38 (0.23–0.62)§ | 0.69 (0.27–1.76) | 0.60 (0.30–1.17) |
Q3 | 0.38 (0.27–0.55)§ | 0.13 (0.07–0.25)§ | 0.31 (0.19–0.51)§ | 0.46 (0.16–1.27) | 0.30 (0.14–0.60)¶ |
Q4 | 0.27 (0.18–0.40)§ | 0.13 (0.06–0.25)§ | 0.31 (0.18–0.54)§ | 0.14 (0.04–0.42)¶ | 0.22 (0.09–0.50)§ |
*Phases based on dominant circulating strain: March 22–August 15, 2021 (pre-Delta, primarily Mu, Gamma, Iota, and Lambda strains), August 16–December 23, 2021 (Delta), December 24, 2021–April 30, 2022 (Omicron, BA.1), and May 1–August 17, 2022 (Omicron, BA.2, BA.4, BA.5). Anti-S, SARS-CoV-2 spike binding antibody. †Odds ratios with 95% CIs calculated using binomial multivariable logistic regression models with data presented for log-adjusted anti-S titers stratified by quartile. Quartiles calculated using the quantile function in R (16) and are specific to each phase. Appendix Table 10 shows phase and quartile anti-S geometric mean titers and median titers Model covariates include, in addition to anti-S titer quartile, number of COVID-19 vaccine doses received, days since last COVID-19 vaccine dose, sex, age, and month of sample collection. Appendix Tables 4–8 show full univariable and multivariable models, underlying data, predictor variables, and model performance measures. §p<0.001. ¶p<0.01.