THE SECOND COVID-19 mRNA vaccine dose has been established as safe from allergic reactions that were experienced in the first dose, says a multi-hospital analysis led by allergists from Massachusetts General Hospital (MGH), USA. The study suggested that a reaction to the first dose of the COVID-19 vaccine should not keep affected individuals from receiving the second dose.
The combined study was carried out by researchers from MGH; Vanderbilt University Medical Center (VUMC), Tennesse, USA; University of Texas Southwestern Medical Center, USA; and Yale School of Medicine (YSM), Connecticut, USA. Anaphylaxis, the life-threatening allergic reaction, following the first COVID-19 vaccination has been disclosed to have occurred in up to 2.5 per 10,000 individuals. In order to examine whether it was safe to progress with the second COVID-19, the researchers collated data from patients who consulted with allergy specialist care at their hospitals following an allergic reaction from their first mRNA COVID-19 vaccine dose.
Out of a total of 189 patients, 32 individuals suffered anaphylaxis attack following the first dose of the mRNA COVID-19 vaccine. A total 159 patients received and tolerated the second dose, including 19 patients who had initially experienced anaphylaxis after the first dose. Allergic symptoms were only experienced by 32 individuals following the second dose and these symptoms were resolved by the use of antihistamines alone.
“One important point from this study is that these immediate onset mRNA vaccine reactions may not be mechanistically caused by classic allergy, called immediate hypersensitivity or Ig-E-mediated hypersensitivity. For classic allergy, re-exposure to the allergen causes the same or even worse symptoms,” says co-senior author Kimberly G. Blumenthal, Co-director of the Clinical Epidemiology Program within MGH’s Division of Rheumatology, Allergy, and Immunology.