Monitoring Temporal Changes in SARS-CoV-2 Spike Antibody Levels and Variant-Specific Risk for Infection, Dominican Republic, March 2021-August 2022

To assess changes in SARS-CoV-2 spike binding anti-body prevalence in the Dominican Republic and impli-cations for immunologic protection against variants of concern, we prospectively enrolled 2,300 patients with undifferentiated febrile illnesses in a study during March 2021-August 2022. We tested serum samples for spike antibodies and tested nasopharyngeal samples for acute SARS-CoV-2 infection using a reverse transcription PCR nucleic acid amplification test. Geometric mean spike an-tibody titers increased from 6.6 (95% CI 5.1-8.7) binding antibody units (BAU)/mL during March-June 2021 to 1,332 (95% CI 1,055-1,682) BAU/mL during May- August 2022. Multivariable binomial odds ratios for acute infection were 0.55 (95% CI 0.40-0.74), 0.38 (95% CI 0.27-0.55), and 0.27 (95% CI 0.18-0.40) for the second, third, and fourth versus the first anti-spike quartile; find-ings were similar by viral strain. Combining serologic and virologic screening might enable monitoring of discrete population immunologic markers and their implications for emergent variant transmission.

Automated summary

To assess the changes in SARS-CoV-2 spike binding antibody prevalence and its implications for immunologic protection against variants of concern, a prospective study was conducted in the Dominican Republic from March 2021 to August 2022, involving 2,300 patients with undifferentiated febrile illnesses. Serum samples were tested for spike antibodies and nasopharyngeal samples were tested for acute SARS-CoV-2 infection. The study found that geometric mean spike antibody titers significantly increased over time, and higher antibody levels were associated with reduced odds of acute infection, regardless of the viral strain. The combination of serologic and virologic screening could help monitor population immunologic markers and their impact on emerging variant transmission.