Studies provide insights into SARS-CoV-2 immunity among dialysis recipients

Despite weakened immunity Received dialysis Data from samples from US dialysis facilities showed that receptor-binding domain IgG antibody levels persisted for at least 6 months after SARS-CoV-2 infection.

In a second Canadian study, a single dose of the Pfizer / BioNTech vaccine was “humoral immunity” in most dialysis recipients who were not pre-infected with SARS-CoV-2, even after “long-term observation.” The response could not be elicited. ” This study also showed a delayed response in patients previously infected with SARS-CoV-2.

“Really benchmark”

In the first study Shuchi Anand, MD, MS, The director of the Tubular Interstitial Kidney Disease Center at Stanford University and colleagues collaborated on the SARS-CoV-2 antibody in July 2020 to assess the persistence of the SARS-CoV-2 receptor binding domain (RBD). We prospectively reviewed plasma from 2,215 dialysis recipients who were positive for. ) IgG for 6 months or more.

“At this time, this type of work is a true benchmark for assessing response to vaccination, for example, the protection that patients may have received after vaccination compared to people with natural infections. It helps clinicians make decisions, “Anand told Healio Primary Care.

Anand and colleagues reported in Annual report of internal medicine 93% of patients showed an assay-detectable response (IgG index value of 1) during a 6-month follow-up period. Of the 1,323 (60%) participants who had high index values ​​(IgG 10) in July 2020, 76% continued to have high index values ​​in December 2020.

Overall, researchers noted a “slow and continuous decline” in patient-adjusted median index values, starting at 21 in July 2020 and reaching 13 in December 2020 ().P <.001). The patient's age, gender, racial / ethnicity, and diabetic status did not affect the pathway of his or her response. Patients who did not reach a detectable response in the assay were Caucasian, 18-44 years, or 80 years or older and tended to be less likely to have diabetes and hypoalbuminemia.

“I was surprised to see that most patients maintain their antibodies after a natural infection,” Anand said.

“One of the reasons for our discovery may be that this population has comorbidities, but we are studying them after being exposed to SARS-CoV-2 and surviving the infection. , Their health is better than the most sick Patients undergoing dialysis “ Anand said. “Another reason may be data suggesting that people with symptomatological or severe infections have a stronger antibody response.”

Researchers are currently investigating the response of dialysis recipients to COVID-19 vaccination.

“We expect to see a measurable antibody response to SARS-CoV-2 in the majority of people undergoing dialysis, which is the death and other complications of COVID-19 in our population. This means that the risk is low, “says Anand. “If hospitalized with COVID-19, this would be a great public health outcome, as patients undergoing dialysis have the highest risk of death.”

Vaccine efficacy “uncertainty” in dialysis recipients

In the second study, Remi Gupil, MD, MSc, A nephrologist and colleague at Hôpital du Sacré-Coeur de Montréal in Canada reported that the efficacy of the Pfizer / BioNTech vaccine in patients undergoing hemodialysis was “still uncertain.”

The researchers found that 154 dialysis recipients (135 did not previously have SARS-CoV-2 infection) and 40 health care worker controls (half previously had SARS-CoV-2 infection). The Pfizer / BioNTech COVID-19 vaccine was analyzed before and after the first dose of continuous plasma from). They also evaluated convalescent plasma from 16 dialysis recipients who survived COVID-19.

“We tried to determine if it was a short-term antibody response after a single dose. [Pfizer-BioNTech] The mRNA vaccine is comparable between patients undergoing hemodialysis and healthy individuals, and how this compares to the antibody response of patients undergoing hemodialysis who survived the natural infection of SARS-CoV-2. Will it be done? “Goupil et al. Wrote. Canadian Medical Association Journal.

Researchers found that in patients who were not previously infected with SARS-CoV-2, 57% (95% CI, 47-65) and 5% (95% CI, 1-23) controls of dialysis recipients. According to Goupil et al., Patients whose anti-RBD levels were not detected by week 4 had no detectable levels by week 8.

Among patients previously infected with SARS-CoV-2, median anti-RBD IgG levels at week 8 of dialysis recipients were comparable to controls at week 3 (P = 0.3) and convalescent plasma from dialysis recipients recovered from COVID-19 (= 0.3)P = 0.8).

Based on their results, the researchers recommended prioritizing dialysis recipients for a second dose of the Pfizer / BioNtech vaccine within the recommended 3-week interval. The effectiveness is known. ”

reference:

Anand S et al. Intern Med. 2021; doi: 10.7326 / M21-0256.

Goupil R, et al. CMAJ.. 2021; doi: 10.1503 / cmaj.210673.

Outlook

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Paul Komenda, MD, FRCPC, MHA

The limitation of the study by Anand and colleagues is the lack of correlation with symptomatological infections, and due to the timing of the study, it is not possible to conclude much about protection from reinfection with escape variants, which is more common today. .. That said, the results may provide some evidence of the endurance of protective antibodies at 6 months against wild-type infections in older, more prone to comorbidities.

In a second study, Goupil et al. Write that a single dose of the Pfizer / BioNTech vaccine is unlikely to provide antibody-mediated protection for dialysis patients. Due to the vulnerability of this population, it should be prioritized to receive a second vaccination, and the responsiveness and endurance of this vaccine in that population should be tentatively used with mitigation strategies to protect these patients. Further research on sex is needed.

Paul Komenda, MD, FRCPC, MHA

Chief Medical Officer of Quanta Dialysis Technologies
Associate Professor, University of Manitoba School of Medicine
Seven Oaks General Hospital Home Dialysis Program Medical Director

Disclosure: Komenda has not reported disclosure of relevant financial information.

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