Abstract
Simple SummaryVaccination against SARS-CoV-2 is currently the best tool in the fight against the COVID-19 pandemic. However, there are concerns about its efficacy and safety after hematopoietic stem cell transplantation. The aim of the study was to study the efficacy and safety of two doses of BNT162b2 mRNA vaccine in adult patients after autologous or allogeneic transplantation. We examined the presence of anti-SARS-CoV-2 antibodies before and after vaccination. We also searched for the potential predictors of serological conversion after vaccination, including the analysis of the impact of various lymphocyte subpopulations at the time of vaccination on post-vaccine antibody concentration and seroconversion. In addition, patients were followed-up for adverse events after vaccination, and the data on breakthrough SARS-CoV-2 infection were collected. The results of our study broaden the knowledge of the efficacy and safety of BNT162b2 mRNA vaccine in patients after HCT, providing new data on serological conversion predictors.Vaccination against SARS-CoV-2 is currently the best tool in the fight against the COVID-19 pandemic. However, there are limited data on its efficacy and safety after hematopoietic stem cell transplantation (HCT). We present the results of a prospective analysis of the humoral response to two doses of BNT162b2 mRNA vaccine in 93 adult patients, including 29 after autologous HCT (autoHCT) and 64 after allogeneic HCT (alloHCT). Positive anti-SARS-CoV-2 antibodies were detected before vaccination in 25% of patients despite a negative medical history of COVID-19. Seroconversion after vaccination was achieved in 89% of patients after alloHCT and in 96% after autoHCT, without grade 3/4 adverse events. Post-vaccination anti-SARS-CoV-2 antibody level correlated with the time from transplant and absolute B-cell count at the vaccination. In univariate analysis restricted to the alloHCT group, short time since transplantation, low B-cell count, low intensity conditioning, GvHD, and immunosuppressive treatment at the vaccination were associated with lack of seroconversion. In the multivariate model, the only negative predictor of seroconversion remained treatment with calcineurin inhibitor (CNI). In conclusion, the BNT162b2 mRNA vaccine is highly immunogenic in patients after HCT, but treatment with CNI at the time of vaccination has a strong negative impact on the humoral response
Highlights
According to a WHO report, over 270 million cases of SARS-CoV-2 infection have been registered worldwide, and the COVID-19 epidemic has claimed over 5 million lives [1]
Among patients after autologous hematopoietic stem cell transplantation (HCT), 48% were treated due to multiple myeloma, and the remaining patients were transplanted for lymphoma
The intensity of the conditioning regimens in the allogeneic HCT (alloHCT) group was determined according to the Transplant Conditioning Intensity (TCI) score [15] as low, intermediate, or high
Summary
According to a WHO report, over 270 million cases of SARS-CoV-2 infection have been registered worldwide, and the COVID-19 epidemic has claimed over 5 million lives [1]. Apart from fatalities, COVID-19 carries many other serious complications, especially in hematological patients [2]. Due to the low effectiveness of available drugs against COVID19 [3], the best tool in the fight against this disease is the strategy of wide-spread vaccination. The necessity of carrying it out in a wide group of people with various clinical conditions causes many questions about the effectiveness and safety of vaccinations [4]. As shown by many studies in this population, SARS-CoV-2 infection is associated with a significantly higher risk of progression to the severe form of COVID-19 and a worse prognosis if this occurs [5,6]
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