Aplastic anemia following varicella vaccine

Aplastic Anemia in the light of the COVID-19 pandemic: infection, vaccination, and pathophysiologic mechanisms

Patients infected with SARS-CoV-2 and vaccinated against COVID-19 could develop aplastic anemia (AA). Comprehensive review and analysis were conducted through a selective literature search in PubMed, Scopus, EMBASE, and Web of Science. For this analysis, 26 studies were included, comprising 16 case reports, 7 case series, and 3 observational studies, totaling 53 patients. The causes of acquired or idiopathic AA are diverse; this review presents recent findings, including possible new etiologies such as SARS-CoV-2 infection and COVID-19 vaccines. This possible association is explored, addressing the existing gap, and aiming to improve daily medical practice. This article reviews the relationship between AA and SARS-CoV-2 infection, as well as COVID-19 vaccines, analyzing cases of de novo occurrence and relapses of AA. Although a definitive mechanistic link has not yet been established, possible underlying pathophysiological mechanisms are explored.

Variable Clinical Courses of Varicella Zoster Virus Infection-related or Vaccination-related Bone Marrow Failure

We report 5 children with bone marrow failure (BMF) after primary varicella zoster virus (VZV) infection or VZV vaccination, highlighting the highly variable course. Two patients were treated with intravenous immunoglobulins; one had a slow hematologic recovery, and the other was rescued by allogeneic hematopoietic stem cell transplantation (HSCT). Of the 2 patients treated with immunosuppressive therapy with antithymocyte globulin and cyclosporine, one had a complete response, and the other was transplanted for nonresponse. One patient underwent a primary allograft. All patients are alive. This study demonstrated that VZV-associated BMF is a life-threatening disorder that often requires HSCT.

New-onset aplastic anemia after SARS-CoV-2 vaccination

Aplastic anemia (AA) is a rare autoimmune disease. Drugs, viruses, and radiation are among the most common etiologic factors, and most cases have immune pathophysiology. SARS-CoV-2 vaccines have been linked with rare side effects, including cases of acquired aplastic anemia. Here we review all the reported cases of new-onset AA after SARS-CoV-2 vaccination, and discuss their clinical characteristics and management. 18 patients in these case reports had a median age of 58 years. The time from vaccination to onset of aplastic anemia ranged from 1 day to 7 months, with a median of 2.5 weeks. Seventeen patients were diagnosed with severe or very severe aplastic anemia post-vaccination and all patients received standard treatments for acquired aplastic anemia. Seventeen patients achieved a complete or partial response and only 1 patient died. Aplastic anemia can be considered a very rare SARS-CoV-2 vaccine-related adverse event, although a causative relationship has not been proven. Reporting cases of such uncommon post-vaccination events could help clinicians to consider aplastic anemia when pancytopenia is observed after vaccination. The benefits of SARS-Cov-2 vaccination are established, and reports of rare events serve only to increase awareness in daily clinical practice.

New onset of hypomegakaryocytic thrombocytopenia with the potential for progression to aplastic anemia after BNT162b2 mRNA COVID-19 vaccination

Vaccination with a coronavirus disease-2019 (COVID-19) vaccine is an effective public health measure for reducing the risk of infection and severe complications from COVID-19. However, serious hematological complications after COVID-19 vaccination have been reported. Here, we report a case of new-onset hypomegakaryocytic thrombocytopenia (HMT) with the potential for progression to aplastic anemia (AA) that developed in a 46-year-old man 4 days after the fourth mRNA COVID-19 vaccination. Platelet count rapidly decreased after vaccination and white blood cell count declined subsequently. Bone marrow examination immediately after disease onset showed severely hypocellular marrow (cellularity of almost 0%) in the absence of fibrosis, findings that were consistent with AA. Since the severity of pancytopenia did not meet the diagnostic criteria for AA, the patient was diagnosed with HMT that could progress to AA. Treatment with eltrombopag and cyclosporine was started immediately after diagnosis and cytopenia improved. Although it is difficult to determine whether the post-vaccination cytopenia was vaccine induced or accidental because the association was chronological, vaccination with an mRNA-based COVID-19 vaccine may be associated with development of HMT/AA. Therefore, physicians should be aware of this rare, but serious adverse event and promptly provide appropriate treatment.

An Unusual Case of Acquired Aplastic Anemia following SARS-CoV-2 Vaccination: A Case Report

Aplastic Anemia (AA) is a condition where the body's immune system attacks and destroys the hematopoietic stem cells, leading to pancytopenia and an empty bone marrow. AA can be effectively treated using immunosuppressive therapy or hematopoietic stem-cell transplantation. The damage to stem cells in the bone marrow can be due to several causes, such as autoimmune diseases, medication like cytotoxic drugs and antibiotics, and exposure to toxins or chemicals in the environment. In this case report, we present the diagnosis and treatment of a 61-year-old man who was diagnosed with Acquired Aplastic Anemia, which could have developed following his serial immunizations with the SARS-CoV-2 COVISHIELD viral vector vaccine. The patient received immunosuppressive therapy consisting of cyclosporine, anti-thymocyte globulin, and prednisone, resulting in a significant improvement in his condition.

Very severe immune aplastic anemia after mRNA vaccination against COVID-19 responds well to immunosuppressive therapy: clinical characteristics and comparison to previous reports

OBJECTIVE

Various hematologic side effects of the Coronavirus Disease 2019 (COVID-19) vaccination has been reported, and most of them are thought to be related to autoimmune pathways. To the best of our knowledge, only few cases of post-COVID-19 vaccination aplastic anemia (AA) have been reported and there is no reported Korean case of COVID-19 vaccine-induced AA yet. We present a case of severe immune-mediated AA that developed after the administration of a messenger ribonucleic acid (mRNA) gene-based spike protein vaccine against COVID-19, which responded well to immunosuppressive therapy, and discuss the probable pathogenesis of AA and the implication of vaccination along with a comparison of previous cases reported.

METHODS

A 53-year-old Korean man developed sudden pancytopenia three months after COVID-19 vaccination. To evaluate the cause of pancytopenia, a bone marrow study was performed.

RESULTS

A diagnosis of AA was made through the bone marrow study and he received triple immunosuppressive therapy (IST). After triple IST for five months, his blood cell count was improved and maintained without transfusion and his follow-up bone marrow examination showed improved cellularity.

CONCLUSION

COVID-19 vaccine might be associated with the development of immune-mediated AA. Prompt hematologic evaluation should be performed when there are symptoms or signs suggestive of cytopenia after COVID-19 vaccination. Although the clinical outcome of post-vaccination AA varies, a good prognosis can be possible for patients with COVID-19 vaccination-induced AA.

Severe aplastic anaemia after serial vaccinations for SARS‐CoV‐2, pneumococcus and seasonal influenza

We present a 67‐year‐old woman who developed progressive pancytopenia over 10 months, concomitant with administration of severe adult respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), pneumococcal and influenza vaccines. She developed mild leukopenia ∼2 weeks after the SARS‐CoV‐2 mRNA vaccine sequence, with progressive symptoms after subsequent vaccines, eventually developing severe aplastic anaemia (SAA). While there have been several reports of vaccine‐related SAA, at time of submission, our case is the first reported to develop after the Moderna mRNA SARS‐CoV‐2 vaccine, as well as the first to document the gradual development of SAA over the course of many vaccine exposures. Physicians should be cognizant of vaccine‐associated SAA, considering current widespread coronavirus disease 2019 vaccination efforts.

Acquired aplastic anemia following SARS-CoV-2 vaccination

COVID‐19 is a potential life‐threatening viral disease caused by SARS‐CoV‐2 and was declared a pandemic by the WHO in March 2020. mRNA‐based SARS‐CoV‐2 vaccines are routinely recommended in immune‐compromised patients, including patients with AA, as these patients are at increased risk of contracting COVID‐19 and developing a more severe course of disease. Between March 2021 and November 2021 relapse of AA occurred in four (age [median]: 53 years, range 30–84 years) out of 135 patients currently registered at our department and two de novo cases of AA in temporal context to vaccination against SARS‐CoV‐2, were documented. Median time after first COVID‐19 vaccination and relapse of AA was 77 days. All relapsed patients were vaccinated with the mRNA‐based vaccine Comirnaty®. Relapse in two out of the four patients was refractory to CsA/eltrombopag, favoring IST with hATG/CsA or BMT, respectively. Our observations should prompt clinicians to take vaccine‐induced relapse of AA or de novo AA after SARS‐CoV‐2 vaccination into account. Furthermore, careful clinical monitoring and vigilance for signs or symptoms that may indicate relapse of AA (e.g., bleeding complications) are indicated.

Severe aplastic anemia after COVID-19 mRNA vaccination: Causality or coincidence?

The development of various autoimmune diseases has been reported after COVID-19 infections or vaccinations. However, no method for assessing the relationships between vaccines and the development of autoimmune diseases has been established. Aplastic anemia (AA) is an immune-mediated bone marrow failure syndrome. We report a case of severe AA that arose after the administration of a COVID-19 vaccine (the Pfizer-BioNTech mRNA vaccine), which was treated with allogeneic hematopoietic stem cell transplantation (HSCT). In this patient, antibodies against the SARS-CoV-2 spike protein were detected both before and after the HSCT. After the patient's hematopoietic stem cells were replaced through HSCT, his AA improved despite the presence of anti-SARS-CoV-2 antibodies. In this case, antibodies derived from the COVID-19 vaccine may not have been directly involved in the development of AA. This case suggests that the measurement of vaccine antibody titers before and after allogeneic HSCT may provide clues to the pathogenesis of vaccine-related autoimmune diseases. Although causality was not proven in this case, further evaluations are warranted to assess the associations between vaccines and AA.

Postvaccination graft dysfunction/aplastic anemia relapse with massive clonal expansion of autologous CD8+ lymphocytes

Acquired aplastic anemia is a T-cell–mediated autoimmune bone marrow aplasia, without a known etiologic trigger. Clonal expansion of CD8+ effector T lymphocytes can occur following vaccination and accompany graft dysfunction or aplastic anemia relapse.

Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data

In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10 years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60 years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.

Concise review: Anemia caused by viruses

Most of the viruses known to be associated with anemia in human tend to persistently infect their host and are noncytopathic or poorly cytopathic for blood cell progenitors. Infections with Epstein-Barr virus, cytomegalovirus, varicella-zoster virus, human herpes virus 6 (HHV-6), B19 parvovirus, human immunodeficiency virus, hepatitis A and C viruses and the putative viral agent associated with non-A-G post-hepatitis aplastic anemia have been reported in association with anemia. Nevertheless, a direct cytotoxic effect on erythroid progenitors has been clearly demonstrated only for human parvovirus B19 and evocated for HHV-6. A major role for destructive immunity is strongly suspected in the pathogenesis of anemia associated with the other viral infections. Host genes play a role in the occurrence of virus-induced anemia in animal models, and there are some evidences that genetic background could also influence the occurrence of virus-associated anemia in human.

Postvaccination thrombocytopenia in Canada

Active surveillance data from 12 Canadian tertiary-care hospitals on children hospitalized with postvaccination thrombocytopenia were analyzed. Since 1992, there have been 107 cases reported; while 96% of the children were symptomatic, only 2 had severe bleeding. With treatment, 28 children (26%) had normal platelet counts on discharge from hospital and 93% had documented recovery within 3 months.