Real-world data on bio-clinical follow-up after vaccination with Pfizer-BioNT162b2 mRNA COVID-19 in 216 patients with hematological malignancies

Abstract Hematological malignancies patients (HM) have heterogeneous serological response after vaccination. Real-world data. 216 patients with HM and 12 non-malignant hemopathies received BNT162b2 COVID-19 and monitored for >1 year. The first 43 patients had initial follow-up by telemedicine system (TM). Anti-Spike IgG antibodies were monitored 3-4 weeks post-1 st vaccination and every 3-4 months, by 2 standard bioassays and a rapid serological test (RST). Vaccine boosts were given when the level was <7BAU/mL. Patients who did not seroconvert after 3-4 doses received tixagevimab/cilgavimab (TC). Follow-up and results . Tolerance using TM was good. 15 results were discordant between 2 standard bioassays. Good agreement was observed between standard and RST on 97 samples. After 2 doses, 68% were seroconverted (median 59 BAU/mL) with a median of 162 BAU/mL in untreated patients and 9 BAU/mL in treated patients ( P<0.001 ), particularly for patients receiving rituximab. Patients with low levels of gammaglobulin levels (<5g/L) had reduced seroconversion (p=0.019) . Median levels were 228 BAU/mL post-2 nd dose if seroconverted post-1 st and 2, if seronconverted only post-2 nd . 68% of post-2 nd negative patients were post-3 rd positive. 16 pts received TC, 6 with non-severe symptomatic COVID-19 within 15-40 days. Conclusion : Personalized serological monitoring must be applicated particularly for HM patients.