vaccination

COVID-19 Roundup: Anaphylaxis and Other Reactions After Vaccination

The Cause of Anaphylaxis

In late December 2020, it was speculated that a compound used in the packaging of the mRNA, polyethylene glycol (PEG), could be responsible for the handful of allergic reactions experienced by individuals who received the Pfizer/BioNTech COVID-19 vaccine.

PEG, which is also used in the Moderna vaccine, has never before been included in an approved vaccine, but has been included in various approved drugs that have been shown to induce anaphylaxis in small numbers of individuals.1

CDC Contraindications

As of January 6, 2021, CDC recommends that anyone with a history of immediate allergic reaction of any severity to mRNA COVID-19 vaccine or any component of the vaccine, as well as immediate allergic reaction to polysorbate, should not receive the vaccine and should potentially be referred to an allergist/immunologist.

Further, those with a history of immediate allergic reaction to vaccines or injectable therapies not related to the COVID-19 vaccine should undergo risk assessment, consider deferral of vaccination and referral to an allergist/immunologist, and undergo a 30-minute observation period if vaccinated.2

Anaphylaxis Rate Following Vaccination

According to a January 6, 2021 Morbidity and Mortality Weekly Report, there were 21 cases of anaphylaxis reported among 1.89 million doses of COVID-19 vaccine as of December 23, 2020, which equals 11.1 cases per million, compared with an estimated 1.3 cases per million following inactivated influenza vaccination.

Despite this, they note that anaphylaxis following vaccination against COVID-19 is rare.

“Based on early safety monitoring, anaphylaxis after the Pfizer-BioNTech COVID-19 vaccine appears to be a rare event; however, comparisons of anaphylaxis risk with that associated with non-COVID-19 vaccines are constrained at this time by the limited data available this early in the COVID-19 vaccination program. CDC and FDA will continue enhanced monitoring for anaphylaxis among recipients of COVID-19 vaccines.”3

Vaccinating Health Care Personnel

In December 2020, CDC released recommendations on the vaccination of health care personnel (HCP) and distinguishing between systemic symptoms following vaccination and COVID-19 infection.

Among the recommendations:

  • Vaccination should precede 1 to 2 days off from work.
  • Stagger delivery of the vaccine so that not all HCPs in a single department are vaccinated at once.
  • Develop strategies for evaluating HCPs with systemic symptoms post-vaccination.
  • Offer paid sick leave for HCPs with systemic symptoms post-vaccination.

They also include suggested approaches to evaluating post-vaccination systemic symptoms among HCPs, including:

  • Exclusion of the HCP from work pending evaluation for COVID-19 infection in patients with symptoms consistent with COVID-19 but not with vaccination, including cough, shortness of breath, rhinorrhea, sore throat, loss of taste or smell.
  • HCPs who are afebrile and whose symptoms are limited to those consistent with vaccination (fever, fatigue, headache, chills, myalgia, arthralgia) can return to work if they feel well enough but should be excluded from work if symptoms do not resolve within 2 days.4

—Michael Potts

References:

  1. De Vrieze J. Suspicions grow that nanoparticles in Pfizer’s COVID-19 vaccine trigger rare allergic reactions. News release. Science. Published December 21, 2020. https://www.sciencemag.org/news/2020/12/suspicions-grow-nanoparticles-pfizer-s-covid-19-vaccine-trigger-rare-allergic-reactions
  2. CDC. Interim clinical considerations for use of mRNA COVID-19 vaccines currently authorized in the United States. Updated January 6, 2021. https://www.cdc.gov/vaccines/covid-19/info-by-product/clinical-considerations.html
  3. CDC. Allergic reactions including anaphylaxis after receipt of the first dose of Pfizer-BioNTech COVID-19 vaccine — United States, December 14–23, 2020. MMWR Morb Mort Wkly. Published January 6, 2021. https://www.cdc.gov/mmwr/volumes/70/wr/pdfs/mm7002e1-H.pdf?ACSTrackingID=USCDC_921-DM45827&ACST
  4. CDC. Post vaccine considerations for healthcare personnel. Updated December 13, 2020. https://www.cdc.gov/coronavirus/2019-ncov/hcp/post-vaccine-considerations-healthcare-personnel.html