Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active. of the S1 spike antigen of SARS-CoV-2, at 3 moments: before administering the first dose, before administering the second dose, and 3 weeks after the latter (see Figure 1). Two of 34 patients had positive serology at baseline and were thus excluded from the analysis of seroconversion after vaccination. From the remaining 32, 20 (62.5%) generated detectable IgG antibodies to the receptor-binding domain of the S1 spike antigen of SARS-CoV-2 after only 1 dose whereas 11 (34.38%) responded only after 2 doses were administered. Demographic characteristics, comorbidities, and laboratory parameters were analyzed, seeking correlation between them and either the humoral response intensity (IgG antibodies to the receptor-binding domain of the S1 spike antigen of SARS-CoV-2 titers) or its velocity (seroconversion after 1 dose vs. seroconversion after 2 doses). However, no statistically significant differences were observed between groups (see Table 1). Only 1 patient did not seroconvert after completing vaccination, and, although the patient was a 77-year-old diabetic obese man, we did not find any compelling reason for this lack of response. SARS-CoV-2 vaccination is of particular importance in high-risk populations such as patients on peritoneal dialysis. The 97% of response observed, high in comparison to kidney transplant recipients (25%) 4 and similar to patients on hemodialysis (90%), 5 reinforces the idea that this population should be vaccinated as soon as possible as most of them seroconvert and are therefore likely protected from severe coronavirus disease 2019.