Low circulation of antibodies correlates with risk for COVID-19 among patients on dialysis
Among patients with kidney failure on dialysis, investigators found a low circulation of anti–SARS-CoV-2 antibodies correlated with an increased risk for COVID-19.
Further, the association was independent of vaccine doses.
“In patients receiving dialysis, infection with SARS-CoV-2, even post-vaccination, commonly results in hospitalization and carries the additional risk for in-facility transmission,” Maria E. Montez-Rath, PhD, from the department of medicine at Stanford University, and colleagues wrote. “To date, only half of patients on dialysis have agreed to a third (booster) dose of the mRNA platform vaccines. Although a third dose generates an antibody response in nearly all patients receiving dialysis, the persistence of the response is unknown.”
In a prospective study, researchers examined 3,576 patients on dialysis in the U.S. to determine if circulating antibody levels provided protection against infection in this population. The cohort included unvaccinated and vaccinated patients with one, two or three doses of one or two available mRNA vaccines. Researchers determined clinical diagnoses of COVID-19 during the omicron-dominant period of Dec. 25, 2021, to Jan. 31, 2022, among patients using the U.S. Renal Care electronic health record. Using a log-binomial model accounting for age, sex and prior COVID-19 infections, researchers calculated the relative risk for documented SARS-CoV-2 infection by vaccination and circulating variant receptor-binding domain immunoglobulin G (RBD IgG).
A total of 901 patients were recorded as receiving a third mRNA vaccine dose as of Dec. 1, 2022. Researchers observed SARS-CoV-2 infection in 7% of patients during the omicron-dominant period of the pandemic, and that the risk of infection was higher among those without vaccination or with only one to two doses vs. those who had three doses. Overall, risk for infection was highest among patients with circulating RBD IgG of less than 23 (506 BAU/mL) compared with RBD of at least 23.
“In summary, we demonstrated a meaningful but incomplete degree of protection against infection with the SARS-CoV-2 omicron variant following a third (booster) dose of mRNA platform vaccines. The risk for infection after third vaccine dose is dependent on the antibody response. Ongoing efforts to determine the optimal schedule of SARS-CoV-2 infection surveillance and the utility and timing of antibody testing in patients receiving dialysis should yield benefits to patients receiving dialysis and the public health at large.”
Perspective
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Dialysis patients experience higher rates of COVID-19–related complications than the general population. While some clinicians have ascribed this to the impaired immune systems in dialysis patients, studies have shown the antibody response to vaccination among dialysis patients is robust and better than the response in kidney transplant patients. Because dialysis patients were excluded from the SARS CoV-2 mRNA vaccine trials that led the FDA to issue emergency use authorization and eventual approval, there was little information about the safety and efficacy of these vaccines for dialysis patients.
Do mRNA vaccines and boosters protect dialysis patients from infection with SARS CoV-2? Are these vaccines effective during the current pandemic with the highly infectious omicron variants of SARS CoV-2? Might serial measurements of antibodies help determine when to give additional boosters?
This study from Stanford University, Ascend Clinical Laboratory and U.S. Renal Care examines antibody response and subsequent COVID-19 infection during the omicron variant SARS CoV-2 pandemic. In a nationwide study, with more than 3,500 dialysis patients across 34 U.S. states, and 12% on home dialysis, the authors answered some of these questions. The main findings included the following:
- Infection rates were higher in non-vaccinated patients compared with those who were vaccinated.
- Infection rates were lower in patients receiving a third vaccination dose compared with non-boosted patients.
- Prior to a third (booster) dose, antibody levels (median omicron variant receptor-binding domain) peaked at day 31 to 60 after vaccination and started to decrease by day 61 to 90 and reached a plateau day 120 to 270.
- Antibody levels increased for patients receiving a third immunization, concomitant with the timing of the third dose.
- Patients with low circulating antibody level had higher risk for infection, irrespective of the number of vaccine doses.
- The antibody levels were a better predictor of infection than the number of vaccine doses.
- The authors speculate that serial antibody level measurement in dialysis patients could be useful to direct timing of additional vaccinations, monoclonal antibodies and anti-viral medicines.
This important study demonstrates that mRNA vaccination of dialysis patients offers an effective if incomplete degree of protection against infection with the omicron variants of SARS CoV-2, which is enhanced with a third (booster) dose of vaccine. That protection is dependent on the antibody response. Antibody levels fall starting 2 months after mRNA vaccination. Might it therefore be helpful to monitor antibody levels and individualize timing of boosters according to when each patient’s antibody level falls to a low level? Furthermore, might serial measurement of antibodies identify those dialysis patients with low levels who might best benefit from prophylactic monoclonal antibody or anti-viral therapy? While the authors speculate that serial measurement of antibody levels might be useful in guiding further booster or COVID-19 treatment, this study does not directly address that question. Further studies of serial antibody measurement and possible benefits in guiding therapy need to be done.
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