Antibody Level Predicts the Clinical Course of Breakthrough Infection of COVID-19 Caused by Delta and Omicron Variants: A Prospective Cross-Sectional Study

Abstract

Background Omicron variant viruses spread rapidly, even in individuals with high vaccination rates. This study aimed to determine the utility of the antibody against spike protein level as a predictor of the disease course of coronavirus disease 2019 (COVID-19) in vaccinated patients. Methods Between December 11, 2021, and February 10, 2022, we performed a prospective observational cohort study in South Korea, which included patients infected with Delta and Omicron variants. A multivariable logistic regression analysis to determine the association between antibody levels and outcomes was conducted. The relationship between antibody levels and cycle threshold (Ct) values was confirmed using a generalized linear model. Results From 106 vaccinated patients (39 Delta and 67 Omicron), the geometric mean titers of antibodies in patients with fever (≥37.5°C), hypoxia (≤94% of SpO2), pneumonia, C-reactive protein (CRP) elevation (>8 mg/L), or lymphopenia (<1100 cells/μL) were 1201.5 U/mL, 98.8 U/mL, 774.1 U/mL, 1335.1 U/mL, and 1032.2 U/mL, respectively. Increased antibody levels were associated with a decrease in the occurrence of fever (adjusted odds ratio [aOR], 0.23; 95% CI, 0.12–0.51), hypoxia (aOR, 0.23; 95% CI, 0.08–0.7), CRP elevation (aOR, 0.52; 95% CI, 0.29–0.0.94), and lymphopenia (aOR, 0.57; 95% CI, 0.33–0.98). Ct values showed a positive correlation between antibody levels (P = .02). Conclusions Antibody levels are predictive of the clinical course of COVID-19 in vaccinated patients with Delta and Omicron variant infections. Our data highlight the need for concentrated efforts to monitor patients with severe acute respiratory syndrome coronavirus 2 infection who are at risk of low antibody levels.

Neutralizing antibodies following three doses of BNT162b2 vaccine, breakthrough infection, and symptoms during the Omicron predominant wave

“…Among the cases in our case-control study of third vaccine recipients, higher pre-infection NAb titers against Omicron was associated with fewer symptoms during the Omicron wave. Similarly, in a study of patients infected with Omicron after vaccination, a higher total antibody level within seven days of infection (i.e., peri-infection period) was associated with a lower rate of fever, hypoxia, CRP elevation, and lymphopenia [23]. These findings suggest that pre-infection NAb may play a role in alleviating symptoms of SARS-CoV-2 infection.…”

Prevalence of SARS-CoV-2 Antibodies after the Omicron Surge, Kingston, Jamaica, 2022

“…Regardless of the discrepancy between these studies, only 9.5% of participants in our study had spike IgG levels >1549 bAU/mL, suggesting that the overwhelming majority of persons are likely susceptible to future infections with Omicron or a more immune evasive variant. To our knowledge spike RBD IgG levels have not been assessed in the context of SARS-CoV-2 circulation, but spike antibody levels have been shown to be associated with decreased risk of fever, hypoxia and inflammation when infected with Omicron [5].…”

“…Antibodies against SARS-CoV-2 are useful to determine past infection and to potentially identify persons at risk of In the context of a population with spike-encoding COVID-19 vaccines such as Jamaica, SARS-CoV-2 nucleocapsid IgG can be used to identify persons infected with SARS-CoV-2 in the past [4]. Spike IgG antibodies are the most clinically important type of SARS-CoV-2 antibodies as they can prevent SARS-CoV-2 from binding to ACE-2 receptors and in the context of Omicron have been shown to be associated with a more favorable clinical course of COVID-19 [5].…”

Vaccine Effect on Household Transmission of Omicron and Delta SARS-CoV-2 Variants

“…The patients were already included in another cohort study conducted by the authors. 16 Of the entire cohort, we recruited only those patients who had a history of contact with their household members during the specific period (between two days before and one day after the diagnosis) when SARS-CoV-2 could be transmitted. 17 We defined the patients as index cases if 1) they were the first household members with SARS-CoV-2 infections; and 2) each of them was the only one in the household who could have been a source of SARS-CoV-2 transmission to the other household members.…”