Third dose of COVID-19 vaccine restores immune response in patients with haematological malignancies after loss of protective antibody titres.

We have vaccinated 392 patients with two doses of mRNA COMIRNATY vaccine with an overall antibody response of 70% (best in cMPN, worst in CLL). We have then vaccinated 80 patients who did not achieve seroconversion or were low responders with a third dose of COMIRNATY vaccine. Our first results show promise, especially for patients on anti-CD38 therapy.