ABSTRACT
BACKGROUND:
Humoral response against sudden acute respiratory
syndrome coronavirus 2 (
SARS-CoV-2) after two doses of
BNT162b2 (Pfizer-BioNTech) has been proven to be less intense in
maintenance dialysis patients as compared with
healthy subjects, leading the French authorities to recommend a third
injection in this
population. Here we investigated the response to the third
injection in two cohorts of haemodialysis (HD)
patients.
METHODS:
Data from two prospective observational cohorts were collected. In the first ('systematic') cohort,
patients from two HD centres (n = 66) received a third
injection of
BNT162b2, regardless of the response after two
injections. In the second ('conditional') cohort, the
injection was only prescribed to
patients (n = 34) with no or low response to the previous two doses. In both cohorts, the third
dose was injected 1-2 months after the second
dose.
Serology was performed after the second and third doses to assess anti-Spike
immunoglobulin G (S
IgG) antibody titre.
RESULTS:
In the systematic cohort, anti-S
IgG was found in 83.3 and 92.4% of
patients after the second and third doses of
BNT162b2, respectively. In this cohort, 6/11 (54.5%) and 20/21 (95.2%)
patients switched from non-responder to low responder and from low responder to high responder, respectively. In low and high responders to two doses, 50/55 (90.9%) at least doubled their anti-S
IgG titre.
Similar trends were observed in the conditional cohort.
CONCLUSIONS:
In
maintenance HD
patients, humoral response against
SARS-CoV-2 was boosted after a third
dose of
BNT162b2, allowing
seroconversion in more than half of non-responders. These data may support an intensified
vaccination protocol with a third
dose of
BNT162b2 in
dialysis patients.