Effectiveness of BNT162b2 COVID-19 mRNA vaccine in immunocompromised people


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Immunocompromised patients (ICPs), especially those with hematologic malignancies and lung cancer, are at a higher risk of developing severe coronavirus disease 2019 (COVID-19) compared to the uncompromised population. Some of these serious findings can include ICU admission, invasive ventilation, and death.

To study: BNT162b2 COVID-19 mRNA vaccination in immunocompromised patients: a prospective cohort study. Image Credit: WESTOCK PRODUCTIONS / Shutterstock.com

Background

Clinical trials of the Pfizer-BioNTech BNT162b2 messenger ribonucleic acid (mRNA) vaccine have shown that the vaccine is 95% effective in preventing laboratory-confirmed symptoms of COVID-19. However, trials have ruled out PCIs because their immune response to vaccination cannot be standardized.

Nevertheless, the Israeli Ministry of Health has approved the vaccination of patients on immunosuppressive or biological response modifying therapy associated with any malignant tumor, those who have undergone a solid organ or stem cell transplant or a splenectomy, as well as patients with human immunodeficiency virus (HIV) or primary immune system. deficiency.

The strong correlation between vaccine efficacy, production of protective antibodies from human vaccine studies and a significant immune response, including neutralizing titers of immunoglobulin G (RBD-IgG) and acute respiratory coronavirus severe 2 (SARS-CoV-2) in sera after the first dose, and even more so after the second dose, prompted the evaluation of vaccine efficacy in subpopulations at risk.

In a recent study, Israeli researchers are evaluating the antibody response in PCI with various underlying diseases and assessing correlates of antibody-mediated immunity after vaccination with the Pfizer-BioNTech vaccine.

About the study

A prospective cohort study was conducted at Sheba Medical Center, Israel, between January and April 2020, among 1,274 participants who received the vaccine, including 1,002 ICP and 272 immunocompetent health workers (HCWs).

A total of 1002 selected PCIs had various active malignancies, solid organ transplants (SOT), allogeneic hematopoietic stem cell transplants (HSCT), HIV, chronic lymphocytic leukemia and non-Hodgkin lymphoma (CLL / NHL), multiple myeloma, anti -CD- 38 and autologous bone marrow transplant, and myelodysplastic syndrome (MDS). All patients were treated with some form of immunomodulatory / immunosuppressive drug.

A drug common in most diets was some form of glucocorticosteroid. Patients who had received anti-CD20 monoclonal antibodies in the six months prior to vaccination and patients with acute graft-versus-host disease (GVHD) were excluded, as were patients hospitalized for treatment. induction for acute leukemia, lymphoma or transplantation. Patients with a positive SARS-CoV-2 polymerase chain reaction (PCR) test before or after the first vaccination and during the first week after the second vaccination were also excluded.

All participants were vaccinated 21 days apart, with the two doses of the Pfizer-BioNTech BNT162b2 mRNA vaccine. The antibodies were measured two to four weeks after vaccination by neutralization tests for anti-RBD-IgG antibodies and virus-like viruses against SARS-CoV-2.

Serologic analysis of participants’ samples was tested with enzyme-linked immunosorbent assay (ELISA) to detect IgG antibodies against RBD-SARS-CoV-2. Sera unable to reduce viral replication by 50% at a dilution of 1: 8 or less were considered non-neutralizing. All RBD-IgG positive samples were tested for neutralizing antibodies.

Study results

Statistical analysis showed the highest response rate among HIV patients with 154/156 (98.7%) developing antibodies, with a geometric mean (GMT) of 5.14. Patients with solid malignancies also showed a remarkable response, in which 75/90 (83.3%) developed antibodies, with a GMT of 3.17.

Other groups also showed considerable responses, albeit with lower NA titers. Patients with multiple myeloma responded in 79.7%, those with HSCT 74.8%, liver transplant 69.4%, MDS 60.5%, CLL / NHL 51.0%, kidney transplantation 45.0% and heart transplantation with only 18.8%. For the control group, 269/272 (98.9%) developed antibodies with a GMT of 5.98.

After the second dose, patients positive for HSCT and HIV RBD-IgG developed high neutralizing antibody titers with GMT values ​​of 653.8 and 467.6, respectively. In contrast, heart and kidney transplant patients developed low titers of neutralizing antibodies with GMT values ​​of 53.8 and 89.5, respectively. The GMT for neutralizing antibodies in the control group was 474.

Quantification of IgG following the second dose of BNT162b2 vaccine in immunocompromised patients and immunocompetent health workers. (A) Levels of RBD-IgG. (B) Neutralizing antibodies above the cutoff. The dotted black line indicates the cutoff level of positive antibodies. The short black line indicates GMT time and 95% CI.

Implications

The overall antibody response to the BNT162b2 mRNA vaccine was highly variable among different immunocompromised patients. Thus, individual recommendations should be followed for different classes of immunocompromised patients.

Despite these results, it was observed that younger patients, especially those infected with HIV and with solid malignancies treated with immunochemotherapy, those with multiple myeloma, recipients of HSCT six months after transplantation without GVH, Liver transplant patients, and other transplant patients not receiving immunosuppressive antimetabolite maintenance, were more likely to develop antibody responses. Consequently, vaccination is strongly recommended in these populations.

In contrast, older patients, especially those who had previously received heart and kidney transplants, were less likely to develop an antibody response and should be warned to follow strict infection control measures, especially immunization of all. other members of the household.

This study sheds light on the vaccination strategies to be followed for the most vulnerable population. Vaccinating as many people as possible is currently the only way to prevent the spread of SARS-CoV-2.

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Sara H. Byrd

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