Patients with chronic kidney disease, including those on dialysis, have been prioritized for vaccination due to increased risk of severe COVID-19 outcomes such as hospitalization and death. This is an important population to study as these patients have a reduced immune response to infection and vaccination compared to health care worker controls and plasma from previously infected patients. In a recent preprint, not yet peer-reviewed, several CITF members report that hemodialysis patients produce poor immune response to the Pfizer-BioNTech vaccine.

Key Points:

  • A large proportion of hemodialysis patients had extremely low antibody responses after the first dose of the Pfizer-BioNTech vaccine, but a second dose induced a more robust response.
  • The authors highlight the need for hemodialysis patients to receive the second dose according to the manufacturer’s recommended two-dose schedule for optimal protection.


CITF members Drs. Anne-Claude Gingras, Karen Colwill and Allison McGeer from Sinai Health System, Dr. Sharon Straus from Unity Health Toronto, and Dr. Shelly Bolotin from Public Health Ontario in collaboration with other researchers led by Dr. Michelle Hladunewich from Sunnybrook Health Sciences Centre, looked at the antibody responses of hemodialysis patients. Patients with chronic kidney disease undergoing hemodialysis were recruited from the Sunnybrook Health Sciences Centre in Toronto, Ontario (n=145). A total of 35 healthcare workers were also recruited as healthy controls.

Researchers compared the SARS-CoV-2 antibody levels in hemodialysis patients taken from two groups. The first group had samples taken 28 days after receiving one dose of the Pfizer vaccine. The second group had samples taken prior to and 14 days after the second dose. The results: more patients developed SARS-CoV-2 antibodies to spike (96%) and receptor-binding domain (88%) after receiving two doses compared to those who had received a single dose (80% for spike and 55% for receptor-binding domain). Additional analysis indicated that more participants after two doses had comparable SARS-CoV-2 antibody levels to patients that have recovered from a SARS-CoV-2 infection than patients administered with only one dose (72 vs 41%). All healthcare workers in the control group produced high SARS-CoV-2 spike and receptor-binding domain antibodies following two doses that exceeded the levels found in convalescent plasma.

This study highlights a reduced antibody response among hemodialysis patients 28 days following a single dose of the Pfizer vaccine. This has also been observed by other groups in other compromised populations including patients with cancer and solid organ transplants. Altogether, the authors demonstrated that many hemodialysis patients remain at risk for SARS-CoV-2 infection following the first dose of vaccine and support adherence to the manufacturer’s recommended dosage schedule for more rapid protection. They also note, however, that in contrast to healthy individuals, some of the hemodialysis patients fail at mounting a strong response to the two-dose vaccination regimen, indicating that careful and ongoing monitoring of this patient population is imperative.

Learn about the effectiveness of one dose compared to two doses, as well as the effectiveness of different dosing intervals on our FAQs page here.


Yau K, Abe KT, Naimark D, Oliver MJ, Perl J, Leis JA, Bolotin S, Tran V, Mullin S, Shadowitz E, Garnham-Takaoka J, de Launay KQ, Takaoka A, Straus SE, McGeer AJ, Chan CT, Colwill K, Gingras A-C, Hladunewich MA. The Humoral Response to the BNT162b2 Vaccine in Hemodialysis Patients. medRxiv 2021 May 27. doi: 10.1101/2021.05.24.21257425.