Rochester, NY—Could a graded dosing protocol be the answer for getting patients vaccinated against COVID-19 even though they had an immediate hypersensitivity reaction?

While Rochester Regional Health researchers don’t advise trying the technique outside of a highly controlled trial setting, they report success with the technique in two patients.

The case report in Annals of Internal Medicine describes how second doses of the Moderna vaccine were successfully administered to two patients who reacted to the first one. The key was referral to allergists after a hypersensitivity reaction.

In the first case, a woman aged 64 years with a history of shellfish allergy, received dose one of the Moderna vaccine and experienced skin irritation, hives, and a rapid heartbeat within 10 minutes. She was treated successfully by medical personnel at the vaccination site.

The second patient, a woman aged 39 years with a history of allergic rhinitis, received dose one of the Moderna vaccine and developed hives on her chest and neck within 15 minutes. While medical personnel treated her symptoms at the vaccination site, she developed mild facial swelling and was treated at an emergency department, where she was discharged home after brief treatment.

At an allergy practice where the two patients were referred, skin pricks and intradermal testing showed reaction to the Moderna vaccine. Results from the skin prick were negative for all components in both patients, although both patients had positive results on intradermal testing with the Moderna vaccine, according to the authors.

Both patients worked in the healthcare setting with repeated exposure to patients with COVID-19, however, and didn’t want to automatically forego the second dose, they explain.

The study notes that “guidelines from the Centers for Disease Control and Prevention recommend avoiding subsequent vaccine doses in persons who have any immediate hypersensitivity reaction with the first dose. Although others have reported skin testing protocols to assess the risk of these patients receiving a second dose, there are conflicting opinions about how this information should be used. For other vaccines, if the skin test results are positive and the patient requires subsequent doses, the vaccine is administered in graded doses under observation.”

In light of that, the allergist authors administered the vaccine without premedication through a graded-dosing protocol that used smaller doses of vaccine over five injections given every 15 minutes; patients were observed for reaction throughout the process.

Results indicate that both patients responded well to the graded-dosing protocol and reported no additional symptoms over the following 24 hours. In addition, 3 to 4 weeks after receiving the second dose, both patients had IgG antibodies directed against the spike protein of COVID-19, suggesting vaccination was efficacious despite the graded-dosing protocol.

“Our experience highlights several important points,” the authors write. “First, persons who have an immediate hypersensitivity reaction to dose 1 of the Pfizer-BioNTech or Moderna vaccine should not automatically defer dose 2. Instead, referral to an allergy and immunology physician for further evaluation and management should be considered. Second, although the mechanism of hypersensitivity reaction to messenger RNA vaccines is uncertain, skin testing may guide further vaccine administration. Third, we have shown that dose 2 of the Moderna vaccine can be safely administered through a graded dosing protocol to persons who have symptoms consistent with an immediate hypersensitivity reaction to dose 1, resulting in protective antibodies against COVID-19.

Limitations of our report include the uncertainty surrounding patients who experience anaphylaxis with the first dose of the Moderna vaccine and whether or not a single dose would be sufficiently protective in these persons. Further study in these rare cases is warranted.”

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