Pfizer-BioNTech COVID-19 Vaccine

Introduction

• CDC updated its COVID-19 vaccination recommendations as of Sept 1, 2022 for new bivalent booster vaccines.
• Omicron-containing booster vaccines (all booster doses now bivalent) should retain neutralization for original SARS-CoV-2, induce a strong response against BA.5 and induce broad cross-neutralization against future variants.
• Pfizer-BioNTech COVID-19 Vaccine, Bivalent is restricted to 12 years of age and older as a one-time only booster at least 2 months after either completion of primary vaccination with any monovalent vaccine, or receipt of the most recent booster dose with any monovalent vaccine.
• Only monovalent and not bivalent vaccines are authorized at this time for primary series doses in heretofore unvaccinated persons.
• The 2-month interval for a bivalent booster in the multiply boosted is arbitrary and considerable evidence on boosters in general indicates a longer interval is optimal; further study is required.
• See COVID-19, Vaccines for general vaccine indications, efficacy, duration of protection, choice an

Vaccine

• Type:  Lipid nanoparticle (LNP) encapsulated mRNA
• Pfizer-BioNTech COVID-19 Vaccine, Monovalent (original strain). (Comirnaty, mRNA BNT162b2)
• Pfizer-BioNTech COVID-19 Vaccine, Bivalent (original and Omicron BA.4/BA.5). Not branded at present.

Dose

• Available Pfizer vaccine vials in the US. Choice of vials (differential color-coding) should be under the supervision of a pharmacist.

Schedule (normal host)

Storage

• Store as follows (may vary by country):

  • -90°C to -60°C (-130°F to -76°F): 12 mos
  • -25°C to -15°C (-13°F to 5°F): Do not store
  • 2-8°C (36-46°F): 10 wks
  • 8-25°C (46-77°F): 12 hrs prior to dilution           
  • After first puncture: 2-25°C (36-77°F): Discard after 12 hrs 
  • Purple capped and vials with purple border label have different storage conditions         

Toxicities

Contraindications

• Anaphylaxis or immediate allergic reaction (within 4h) to a previous dose of an mRNA vaccine or separately to a vaccine constituent including polyethylene glycol (PEG) or polysorbate. 
  • Do not vaccinate with any mRNA vaccine
• History of a known diagnosed allergy to a vaccine component

Precautions

• Immediate allergic reaction (within 4h) to any other vaccine or injectable therapy not related to a component of mRNA-COVID-19 vaccines or polysorbate.
• Persons with a reaction to a vaccine or injectable therapy that contains PEG
• History of myocarditis or pericarditis after a dose of an mRNA or Novavax COVID-19 vaccine, avoid future doses of any COVID-19 vaccine
• Allergy-related contraindication to one type of COVID-19 vaccine is a precaution to the other types of COVID-19 vaccines
• Defer vaccination until resolution of a moderate or severe acute illness, with or without fever

Not Contraindications

• Food (including egg and gelatin), pet, insect, venom, environmental, latex, oral medications; any other history of anaphylaxis not related to vaccine or injectables.
• History of GBS in proximity to another vaccine.

Adverse Effects

• Similar safety profile when  monovalent or bivalent vaccine is used as a 4th dose (2nd booster)
• Pain at the injection site, sometimes severe, occurs frequently
• Fatigue, headache, and myalgia common but are mild to moderate, occurring within 1–2 days of vaccination, and resolving within 1–2 days of onset.
  • more frequent following dose 2 and among adolescents and younger adults compared with older adults.
• Myocarditis: 131 myocarditis cases reported to VAERS after 123 million mRNA booster vaccinations
  • Risk primarily in adolescent and young adult males
  • No increase in children ages 5–11 years following 1st booster
  • Rates are lower following 1st booster dose vs. dose 2 of primary series (and lower following dose 1 vs. dose 2 of primary series)
  • 8-week interval between the first and second primary series doses of Moderna, Novavax, and Pfizer-BioNTech COVID-19 vaccines may be optimal for some people to reduce myocarditis.

Pregnancy

• Vaccinate according to standard recommendations if pregnant, breastfeeding, attempting or contemplating conception
  • Pregnant and recently pregnant persons at increased risk for severe illness and the fetus is at increased risk
• Benefits outweighs risks of vaccination
• Antibodies are transferred to the newborn
• No contraindications to breastfeeding

Immunocompromised / HIV

• Self-attestation to moderately or severely immunocompromised status is acceptable
• New immunocompromise after a 2-dose mRNA primary series do not need additional primary doses;  immunocompromised schedule for the booster dose.
• Revaccinate HCT or CAR-T-cell therapy recipients with an mRNA vaccine or Novavax >3 months after HCT or CAR-T-cell therapy 
• Consider revaccination if 1 or more doses of vaccine (primary series and bivalent booster doses) received during short-course treatment with B-cell-depleting therapies (e.g., rituximab, ocrelizumab)  beginning at about 6 months after completion of therapy
• Administration of vaccines should not be delayed in patients on ongoing immunosuppressives
  • Administer vaccine doses approximately 4 weeks before the next scheduled therapy for patients on ongoing B-cell-depleting therapies

Serologic Testing

• Antibody testing is not recommended to assess for immunity following COVID-19 vaccination or to assess the need for vaccination in an unvaccinated person
  • No correlates of protection are available and assays vary widely
  • +ve IgG only minimally reassuring, -ve IgG unhelpful in patients whose ability to mount a B-cell response is uncertain

Comments

• Age-appropriate vaccine product and dosage is based on age on the day of vaccination.
  • a move from a younger age group to an older age group during the primary series, requires the vaccine product and dosage for the older age group
• Vaccines are not recommended for outbreak management or for post-exposure prophylaxis
• mRNA vaccines do not have a risk of modifying the vaccine recipient’s genetic makeup as mRNA does not enter cell nucleus where host DNA is located.