Autoimmune hemolytic anemia after COVID-19 vaccination
Until March 10th 2023, the Netherlands Pharmacovigilance Centre Lareb received 10 reports of auto-immune hemolytic anemia (AIHA) following COVID-19 vaccination. AIHA is not a known side effect of the COVID-19 vaccines. A causal relationship between AIHA and the COVID-19 vaccines is possible, but based on the reports and literature no conclusion can be made.
AIHA is a rare autoimmune disorder where the immune system attacks red blood cells which leads to hemolysis and anemia. AIHA often presents with symptoms of fatigue, shortness of breath, dizziness and pale skin. The symptoms can be mild, but severe anemia with associated problems can occur.
Lareb reports
The reporters received:
- 7 times the Moderna vaccine (Spikevax),
- 1 time the Pfizer/BioNTech vaccine (Comirnaty)
- 1 time the AstraZeneca vaccine (Vaxzevria)
- 1 time a non-specified COVID-19 vaccine
In 6 reports a recurrence of AIHA was reported with a mean time to onset of 6 days. A new diagnosis of AIHA was seen in the other 4 reports with a mean time to onset of 20 days after vaccination. Other causes for (the recurrence of) AIHA were excluded in most cases.
6 reports were received via a multicentre retrospective cohort study in which individual cases are retrieved from electronic healthcare databases in two Dutch hospitals. The other 4 reports were originated from the spontaneous report system at Lareb.
The mechanism of AIHA following vaccination is unknown
One hypothesis is based on molecular mimicry between the SARS-Cov-2 spike protein and ankyrin-1 on the membrane of red blood cells. This could lead to cross-reactivity which may contribute to the development and exacerbation of AIHA following COVID-19 vaccination.