Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 27, 2024 4 days, 1 hour, 24 minutes ago
COVID-19 News: Introduction: What is Acquired Hemophilia A?
Acquired Hemophilia A (AHA) is a rare bleeding disorder caused by the immune system attacking the body’s own clotting factor VIII. Unlike congenital hemophilia, which is present from birth, AHA develops suddenly and can lead to severe, spontaneous bleeding. Although it is a rare condition, with an incidence of approximately 1.4 cases per million people per year, it carries significant risks, including a high rate of morbidity and mortality.
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Acquired Hemophilia A - A Rare Side Effect of COVID-19 Vaccines
AHA and COVID-19 Vaccination: What's the Connection?
Since the outbreak of COVID-19, millions of people worldwide have received vaccinations to protect against the virus. However, there have been concerns and reports about rare side effects associated with these vaccines. One such rare side effect is the potential development of AHA. This
COVID-19 News report covers a study review by researchers from University of Sassari-Italy, Luigi Sacco Hospital, University of Milan-Italy, Fondazione Istituto di Ricerca e Cura a Carattere Scientifico Ca’ Granda Ospedale Maggiore Policlinico-Italy and Centro Immunotrasfusionale Azienda Ospedaliera per i Servizi Sanitari (APSS) Ospedale di Rovereto-Italy that aimed to evaluate the evidence surrounding this possible association and to understand how the immune response triggered by the vaccine might lead to such a condition.
How Does AHA Develop?
AHA occurs when the body produces autoantibodies that neutralize factor VIII, a protein essential for blood clotting. This can lead to severe and uncontrolled bleeding. The bleeding patterns in AHA are different from those seen in congenital hemophilia. Patients typically experience bleeding into the skin, muscles, and mucous membranes, rather than joints.
The condition is more common in older adults and is often associated with other health issues such as autoimmune diseases, cancers, and infections. However, about 50% of AHA cases occur in patients with no identifiable underlying conditions.
The Role of the Immune System in AHA
The immune system plays a crucial role in AHA. Normally, the immune system protects the body from infections and diseases. However, in autoimmune disorders like AHA, the immune system mistakenly attacks the body’s own proteins. In the case of AHA, it targets factor VIII, leading to its destruction or inhibition.
COVID-19 and Autoimmunity
Autoimmunity can be triggered by various viral infections, including SARS-CoV-2, the virus that causes COVID-19. During an infection, the immune system may produce autoantibodies as a result of molecular mimicry, where the immune system mistakenly identifies the body’s own proteins as foreign.
Several studies have reported the development of autoantibodies in patients with COVID-19. These autoantibodies can attack different components of the body, including
clotting factors, leading to conditions like AHA.
COVID-19 Vaccines and Immune Responses
COVID-19 vaccines are designed to trigger an immune response to protect against the virus. There are different types of vaccines, including mRNA vaccines (like Pfizer and Moderna), viral vector vaccines (like AstraZeneca and Johnson & Johnson), and inactivated virus vaccines (like CoronaVac). While these vaccines have been highly effective in preventing COVID-19, they can also stimulate the immune system in ways that might lead to rare autoimmune responses.
Reported Cases of AHA Post Vaccination
The review included 18 manuscripts (2 case series and 16 case reports) documenting cases of AHA following COVID-19 vaccination. Most of these cases occurred after the administration of mRNA vaccines (Pfizer-BioNTech and Moderna), with only one case reported after an inactivated virus vaccine (CoronaVac).
Key Findings
-Age and Comorbidities: Most reported cases involved older adults, many of whom had underlying health conditions such as cardiovascular diseases, diabetes, and previous cancers.
-Vaccine Doses: AHA was observed following the first, second, or booster doses of the vaccines, with a slight increase in cases after the second dose.
-Outcomes: While many patients recovered without severe complications, there were a few instances of severe outcomes, including deaths related to other health complications.
Treatment and Management
Managing AHA involves controlling bleeding and suppressing the immune response to eradicate the autoantibodies. Treatments may include corticosteroids, immunosuppressive drugs, and bypassing agents like recombinant factor VIIa. In some cases, rituximab, a monoclonal antibody, is used to target and reduce the production of autoantibodies.
Conclusion: Weighing the Risks and Benefits
While the occurrence of AHA post COVID-19 vaccination is a rare but serious side effect, the overall benefits of vaccination far outweigh these risks. Vaccines have been instrumental in controlling the COVID-19 pandemic and preventing severe illness and deaths. However, it is important to monitor and study these rare side effects to better understand and manage them.
For individuals, especially older adults with multiple comorbidities, it is crucial to have a thorough assessment before receiving additional vaccine doses. This helps ensure that the benefits of vaccination continue to outweigh any potential risks.
Future Directions
Further research, detailed registries, and prospective studies are needed to explore the connection between COVID-19 vaccination and AHA. Identifying potential markers and risk factors can help healthcare providers better predict and manage this rare side effect, ensuring safer vaccination practices for all.
The study findings were published in the peer reviewed journal: Vaccines.
https://www.mdpi.com/2076-393X/12/7/709
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Read Also:
https://www.thailandmedical.news/news/researchers-warn-about-immune-issues-associated-with-adenovirus-based-vaccines-or-therapeutics
https://www.thailandmedical.news/news/south-korean-preprint-study-five-months-ago-warns-that-covid-19-mrna-vaccines-can-cause-a-variety-of-blood-disorders-including-aplastic-anemia
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