A Study from Iran Before It Was Bombed by the Americans and Israelis Finds That COVID-19 Vaccines Can Trigger Pernicious Anemia
Nikhil Prasad Fact checked by:Thailand Medical News Team Mar 16, 2026 1 hour, 22 minutes ago
Medical News: Rare Blood Disorder Observed After COVID-19 Vaccination
COVID-19 vaccines have been widely credited with saving millions of lives during the global pandemic by preventing severe illness and death. At the same time, researchers around the world continue to monitor rare health events that may occur following vaccination. A new clinical report from Iran has described an unusual case in which a previously healthy adult developed pernicious anemia shortly after receiving a COVID-19 vaccine. Although such occurrences appear to be extremely uncommon, the findings provide new insights into how immune responses may sometimes trigger unexpected medical conditions.
Iranian researchers document a rare case in which pernicious anemia developed shortly after COVID-19 vaccination
in a previously healthy adult.
The case study was conducted by Mahnaz Danesh, Sobhan Parvizi, and Sayyideh Forough Hosseini from Isfahan University of Medical Sciences, along with Pari Hashemi from Golestan University of Medical Sciences in Iran. Their report focuses on a 39-year-old woman who developed severe vitamin B12 deficiency and anemia not long after vaccination.
What Is Pernicious Anemia
Pernicious anemia is a type of autoimmune disease that affects the body’s ability to absorb vitamin B12. This vitamin plays a crucial role in producing healthy red blood cells and maintaining the proper functioning of the nervous system. In people with this disorder, the immune system mistakenly attacks a stomach protein called intrinsic factor, which is necessary for vitamin B12 absorption in the intestines.
When vitamin B12 cannot be properly absorbed, the body begins producing abnormal red blood cells that are larger than normal and unable to function effectively. This leads to a condition called macrocytic anemia. Common symptoms include fatigue, weakness, dizziness, pale skin, and shortness of breath. If the condition goes untreated for a long period, nerve damage and neurological problems can also develop.
In most cases, pernicious anemia develops gradually over many months or even years. However, the patient described in this Iranian study experienced a much more sudden onset of symptoms.
Symptoms Appeared Weeks After Vaccination
According to the doctors involved in the case, the woman began experiencing increasing fatigue, lightheadedness, and shortness of breath during physical activity about three weeks after receiving her second dose of the ChAdOx1 nCoV-19 COVID-19 vaccine.
Before this event, she had no major health problems and maintained a normal diet that included foods rich in vitamin B12. She did not smoke and consumed alcohol only occasionally. The sudden appearance of symptoms therefore raised concerns among the medical team.
During physical examination, the patient appeared noticeably pale and had a mildly elevated heart rate. Blood tests revealed macrocytic anemia, a condition in which red blood cells are unusually large. Laboratory findings also showed extremely low vitamin B12 levels and biochemical markers confirming a true deficiency.
gt;
Further testing detected antibodies against intrinsic factor, indicating that the patient had developed an autoimmune reaction interfering with vitamin B12 absorption.
Stomach Examination Revealed Underlying Damage
Doctors performed an upper gastrointestinal endoscopy to examine the stomach lining more closely. The procedure revealed thinning of the stomach lining and reduced folds in certain areas of the stomach, particularly in the upper regions.
Biopsy samples confirmed the presence of chronic atrophic gastritis, a form of stomach inflammation that is commonly associated with pernicious anemia. Doctors also conducted a bone marrow examination to rule out other serious blood disorders. The bone marrow findings showed classic signs of megaloblastic anemia, confirming that vitamin B12 deficiency was the primary cause of the abnormal blood cell development.
Rapid Recovery After Treatment
After confirming the diagnosis, doctors began treatment using intramuscular vitamin B12 injections. The treatment plan included daily injections for the first week, followed by gradually spaced doses over the next several weeks.
The patient responded quickly to the therapy. Within four weeks, her fatigue and breathing difficulties had resolved completely. By the eighth week, laboratory tests showed that her hemoglobin levels had returned to normal and vitamin B12 levels had significantly increased.
During follow-up examinations six months later, doctors found that inflammation in the stomach had decreased and previously detected antibodies were no longer present in the patient’s blood. One year after treatment began, she remained healthy and symptom-free.
This
Medical News report illustrates how unusual immune reactions can sometimes occur following strong immune stimulation, even though such events remain extremely rare.
Possible Immune System Mechanisms
Scientists believe the immune response triggered by vaccination could theoretically activate autoimmune reactions in susceptible individuals. One proposed explanation is molecular mimicry, where immune responses directed against viral components may mistakenly target similar structures in the body’s own tissues.
Another possibility is that vaccination may reveal or accelerate a previously silent autoimmune process that had not yet produced symptoms. Determining which of these mechanisms may have occurred in this case remains uncertain, and further research is required to fully understand these rare events.
Conclusion
This unusual clinical case highlights a rare instance in which pernicious anemia appeared shortly after COVID-19 vaccination in a previously healthy adult. While the timing suggests that immune activation could have contributed to triggering or revealing the condition, the evidence does not establish a direct causal relationship. What is clear, however, is that early recognition and prompt treatment with vitamin B12 injections resulted in a full recovery for the patient.
The findings also reinforce the importance of continued monitoring and reporting of rare medical events so that scientists can better understand the complex interactions between vaccines, the immune system, and autoimmune diseases while maintaining confidence in vaccination programs.
The study findings were published on a preprint server and are currently being peer reviewed.
https://www.researchsquare.com/article/rs-8874389/v1
For the latest on COVID-19 vaccines, keep on logging to Thailand
Medical News.
Share
Tweet
Share
