Robert T, Lano G, Giot M, et al. - As HD patients are known to exhibit a reduced response to vaccination and weaker maintenance of protective antibodies against coronavirus disease 2019 (COVID-19), researchers sought to determine the persistence of humoral response and the utility of third dose in non-responders following two injections of SARS-CoV2 vaccine in patients under hemodialysis (HD).

• Humoral response was measured at 1, 2 and 3 months after vaccination stratified by history of COVID19 (Time point M1, M2 and M3).

• Patients negative for both antispike IgG antibody (Sab) and neutralizing antibodies (Nab) were defined as non-responders, while those positive for Sab and negative for Nab defined partial responder and positivity for both Sab and Nab was recorded in full responder.

• Non-responder and partial responders were administered a third dose of vaccine, and the response was determined after 1 month of the third dose.

• In HD patients, vaccination with mRNA vaccine is effective and the humoral response could be reinforced by providing a third dose.

• Regarding the real level of protection with the NaB, a non-impressive effect of two doses was evident with only 50% of patients exhibiting a full protection at M1.

• At M3, this status was conserved in only 50% of the full protected patients at M1.

• The humoral response for both Sab and Nab may improve and its longevity may enhance following the third dose.

• Hemodialysis patients should systematically receive a third dose in order to generate a strong and a more sustainable protection against the risk of COVID-19 at short and mid-term.

• For improving immune responses and limiting the non-responder in HD patients, researchers support implementing a ‘mix and match’ approach to SARS-CoV-2 vaccination.