Predictors of impaired antibody response after SARS-CoV-2 mRNA vaccination in hematopoietic cell transplant recipients: A Japanese multicenter observational study.

HCT recipients reportedly have a high mortality rate after developing COVID-19. SARS-CoV-2 vaccination is generally useful to prevent COVID-19. However, its safety and efficacy among HCT recipients remain elusive. This large-scale prospective observational study including 543 HCT recipients with 37-months interval from transplant demonstrated high safety profiles of mRNA vaccine: only 0.9% of patients avoided the second dose due to adverse event or GVHD aggravation following the first dose. Regarding the efficacy, serological response with a clinically relevant titer (≥250 BAU/mL) was obtained in 397 (73.1%) patients. We classified the remaining 146 patients as impaired responders and compared the clinical and immunological parameters between two groups. In allogeneic HCT recipients, multivariable analysis revealed the risk factors for impaired serological response as follows: age (≥60, 1 points), HLA-mismatched donor (1 points), use of systemic steroids (1 points), absolute lymphocyte counts (<1000/µL, 1 points), absolute B-cell counts (<100/µL, 1 points), and serum IgG level (<500 mg/dL, 2 points). Notably, the incidence of impaired serological response increased along with the risk scores: patients with 0, 1-3, and 4-7 points were 3.9%, 21.8%, and 74.6%, respectively. In autologous HCT recipients, a shorter interval from transplant to vaccination was the only risk factor for impaired serological response. Our findings indicate that two doses of SARS-CoV-2 vaccine are safe but insufficient for a part of HCT recipients with higher risk scores. To improve this situation, we should consider additional treatment options, including booster vaccination and prophylactic neutralizing antibodies during the SARS-CoV-2 pandemic.

Surveillance of the current situation regarding influenza vaccination according to medical oncologists in Japan.

This study aimed to clarify the attitude of oncologists toward influenza vaccination and the current situation and issues regarding influenza vaccination for patients on chemotherapy in Japan. A web-based survey of medical oncologists certified by the Japanese Society of Medical Oncology was conducted between November 1 and December 31, 2019. Of the 1369 medical oncologists who were invited to participate, 415 (30.3%) responded to our survey. The questionnaire comprised 4 sections: "oncologist characteristics," "oncologist attitude toward influenza vaccines and the current status of influenza vaccination for cancer patients undergoing chemotherapy," "incidence of influenza infection and associated treatment complications," and "treatment policy for influenza infection." In total, 153 (36.9%) physicians replied that they did not actively encourage influenza vaccination for patients undergoing chemotherapy. The primary reasons given were lack of evidence (48/153, 31.4%) and uncertainty of appropriate timing (46/153, 30.1%). There was diverse variation in the timing of vaccination and in the levels of encouragement based on the cancer location and medication type. Two hundred eighty-three (68.2%) oncologists reported that their cancer patients had experienced influenza infection while undergoing chemotherapy, and 169 (40.7%) responded that their patients had experienced an administration delay or discontinuation of medication because of influenza infection. Our surveillance revealed some oncologists considered evidence regarding the administration of influenza vaccine to cancer patients undergoing chemotherapy (particularly the optimal timing and level of recommendation by cancer location and medication) to be lacking. It also exposed the adverse impact of influenza infection in cancer patients.