Vaccines and Mast Cell Activation Syndrome

What do vaccines have to do with mast cell activation syndrome?

Vaccines and Mast Cell Activation Syndrome

What is mast cell activation syndrome?

Mast cell activation syndrome (MCAS) is a type of mast cell activation disorder. Others include mastocytosis (increased mast cells) and mast cell leukemia.

Patients with MCAS have a normal number of mast cells (part of our immune system and involved with allergic reactions), but they are hyperresponsive.

“Mast cell activation syndrome (MCAS) causes a person to have repeated severe allergy symptoms affecting several body systems. In MCAS, mast cells mistakenly release too many chemical agents, resulting in symptoms in the skin, gastrointestinal tract, heart, respiratory, and neurologic systems.”

Mast cell activation syndrome

The end of result of having either extra mast cells or hyperresponsive mast cells are that you are more likely to have allergic reactions, including severe allergic reactions (anaphylaxis), after being exposed to specific triggers.

Can vaccines be one of those triggers?

Maybe.

But so can vaccine-preventable diseases, so in general, it is recommended that people with a mast cell activation disorder get vaccinated and protected and that they don’t delay or skip any of their vaccines.

And everyone should understand that even as anaphylaxis from vaccines is rare, death following anaphylaxis is even rarer!

COVID-19 Vaccines and Mast Cell Activation Syndrome

Not surprisingly, with the reports of a small extra risk of anaphylaxis with our COVID-19 vaccines, people with mast cell activation disorders are appropriately concerned about the risks and benefits of getting vaccinated.

“Although patients with MC activation disorders including mastocytosis are at risk for MC activation and anaphylaxis when exposed to certain drugs and procedures, there is no evidence of increased sensitization or reactivity to PEG. Patients with MC activation disorders may be good candidates for mRNA severe acute respiratory syndrome coronavirus 2 vaccines whenever indicated, with premedication, in an appropriate setting (hospital with available intensive care unit) and under medical surveillance.”

mRNA COVID-19 vaccine is well tolerated in patients with cutaneous and systemic mastocytosis with mast cell activation symptoms and anaphylaxis

Fortunately, we are already seeing case reports demonstrating that these vaccines are safe and we have some guidance from the American College of Allergy, Asthma, and Immunology:

“Data related to risk in individuals with a history of allergic reactions to previous vaccinations and/or mast cell activation syndrome/idiopathic anaphylaxis is very limited and evolving. A clinical decision to administer the Pfizer-BioNTech COVID-19 vaccine should be undertaken by the physician or other provider administering the vaccine using their professional judgment and in consultation with the patient, balancing the benefits and risks associated with taking the vaccine.”

American College of Allergy, Asthma, and Immunology (ACAAI) Guidance on Risk of Allergic Reactions to the Pfizer-BioNTech COVID-19 Vaccine

What are the benefits of getting vaccinated and protected with a COVID-19 vaccine?

You reduce your risk of getting a life-threatening disease!

“While any stressor can cause a flare in symptoms of mast cell activation, getting vaccines will not worsen a clonal disease permanently. There are currently several hundred patients with mastocytosis around the world and no exacerbation of mast cell symptoms have been observed.”

The Mast Cell Disease Society COVID-19 Statement

What’s the risk of getting vaccinated, even if you have mast cell activation syndrome?

“So far, our physicians have been reporting that patients with mast cell disease are great candidates for the COVID19 vaccines that are mRNA vaccines, and have been tolerating them very well.”

The Mast Cell Disease Society COVID-19 Statement

So far, unlike the SARS-CoV-2 virus, experts are finding that COVID-19 vaccines are safe, even if you have mast cell activation syndrome.

More on Vaccines and Mast Cell Activation Syndrome

• Do Vaccines Cause Mastocytosis?
• Allergic Reactions to COVID-19 Vaccines
• COVID-19 Vaccine Ingredients
• Can Vaccines Cause Cytokine Storm?
• Do Vaccines Cause Food Allergies?
• Can Vaccines Cause Eczema?
• Can Vaccines Cause POTS?
• How Often Do Severe Events Occur After Vaccines?
• The Mast Cell Disease Society COVID-19 Statement
• Mast cell activation syndrome
• Mast Cell Activation Syndrome (MCAS)
• Symptoms and Triggers of Mast Cell Activation
• The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 64
• American College of Allergy, Asthma, and Immunology (ACAAI) Guidance on Risk of Allergic Reactions to the Pfizer-BioNTech COVID-19 Vaccine
• Adverse reactions to drugs and biologics inpatients with clonal mast cell disorders: A WorkGroup Report of the Mast Cells Disorder Committee, American Academy of Allergy, Asthma & Immunology
• Drug hypersensitivity in clonal mast cell disorders: ENDA/EAACI position paper
• Delving Into COVID-19 Vaccination-Induced Anaphylaxis: Are mRNA Vaccines Safe in Mast Cell Disorders?
• mRNA COVID-19 vaccine is well tolerated in patients with cutaneous and systemic mastocytosis with mast cell activation symptoms and anaphylaxis
• Ethanol Allergy or Sensitivity and COVID19 Vaccine 
• Mast Cell Activation Disorder – Yes, It’s Real