Anti-SARS-COV-2 antibodies decline rapidly in haemodialysis patients

Haemodialysis (HD) patients are at higher risk of contracting infection by the SARS-CoV-2 virus, for their antibodies are lower and the titre declines faster than in the general population, according to a study.

The study included 808 HD patients, among whom 136 (16.8 percent) were diagnosed with symptomatic COVID-19 by nasopharyngeal RT-PCR and 42 of them (31 percent) died. This corresponded to an incidence rate of COVID-19 of 5,147 cases per 100,000 HD patients.

Infection rate, anti-SARS-CoV-2 body dynamics, and the incidence of asymptomatic SARS-CoV-2 infection (defined by positive RT-PCR, IgM-IgA, or IgG) were evaluated in the remaining 763 surviving patients. At this point, 69/91 (75.8 percent) symptomatic COVID-19 patients had anti-SARS-CoV-2 antibodies. Four weeks later, 15.4 percent (10/65) of initially antibody positive patients had become negative.

In the group of patients without prior symptomatic COVID-19, 9/672 (1.3 percent) were RT-PCR positive and 101/672 patients (15.0 percent) were antibody positive. Four weeks later, 62/86 (72.1 percent) of initially antibody positive patients had become negative.

Considering only IgG titres, serology remained positive after 4 weeks in 90 percent (54/60) of patients with symptomatic COVID-19 and in 52.5 percent (21/40) of those who were asymptomatic.

Compared with those who had asymptomatic SARS-CoV-2 infection, patients with symptomatic COVID-19 had a greater likelihood of an adequate serologic response (defined as the development of anti-SARS-CoV2 antibodies that persisted at 4 weeks; odds ratio [OR], 4.04, 95 percent confidence interval [CI], 2.04–7.99).

Living in a nursing home (OR, 5.9, 95 percent CI, 2.3–15.1) was the main risk factor for SARS-CoV-2 infection in this population.

The findings raise questions about the susceptibility of HD patients to reinfection and the response to the SARS-CoV-2 vaccine. More studies in dialysis patient-specific vaccine are needed to explore the antibody response and the optimal vaccination schedule.