Antibody response to SARS-CoV-2 natural and breakthrough infection in patients undergoing maintenance hemodialysis: A prospective cohort study over 4 months.

BACKGROUND

Patients undergoing maintenance hemodialysis (MHD) are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the antibody response of these patients to natural and breakthrough infections remains poorly understood.

METHODS

Between January 15, 2023, and February 15, 2023, a total of 53 patients undergoing MHD and diagnosed with SARS-CoV-2 infection at The Affiliated Hospital of Hangzhou Normal University were enrolled. They were categorized into the natural (n = 40) and breakthrough infection groups (n = 13) based on their vaccination status before infection. Comprehensive data, including basic clinical information, vaccination status, and routine post-infection blood parameters, were collected from all participants. Blood specimens were drawn monthly after infection, and SARS-CoV-2 receptor-binding domain (RBD) immunoglobulin (Ig) G and IgM tests were conducted. The study included continuous follow-up over 4 months.

RESULTS

During the acute phase of infection, the SARS-CoV-2 RBD IgM positivity was 5 % in patients undergoing MHD who were naturally infected and 15.4 % in those with breakthrough infections. Four months after infection, SARS-CoV-2 RBD IgG positivity in patients with natural and breakthrough infection was 77.5 % and 100 %, respectively. Patients undergoing MHD with breakthrough infection exhibited higher SARS-CoV-2 RBD IgG titers (751.21 signal-to cutoff ratio, S/CO [interquartile range, IQR, 30.54-1173.63]) than those with natural infections (3.43 S/CO [IQR, 1.12-15.6]) (p < 0.0001). No significant differences were observed in SARS-CoV-2 RBD IgG between males and females or among those aged <70 and ≥70 years. Patients who received three doses of the inactivated vaccine produced significantly higher SARS-CoV-2 RBD IgG levels after infection than those who received one or two doses; these differences were significant.

CONCLUSIONS

Although patients undergoing MHD exhibit a low rate of SARS-CoV-2 RBD IgM positivity following infection, those vaccinated with inactivated vaccines can generate elevated SARS-CoV-2 RBD IgG levels, particularly those who receive three doses.