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Covid-19 Vaccine

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Covid-19 Vaccine, Covid19 Immunization, Corona Virus 19 Vaccination

  • Background
  1. Encourage Vaccination in all adult patients (approval in children is pending study as of spring 2021)
  2. All U.S. Vaccines are considered safe
    1. Patients should get whichever Vaccine is available
    2. Efficacy does favor the mRNA Vaccines as of late 2021
  3. Any of the U.S. Vaccines may be used in Immunocompromised patients (none are live virus, no "viral shedding")
    1. However, immune response to Vaccination may be blunted especially if on chronic Corticosteroids
  4. The covid Vaccines are safe in pregnancy and Lactation
    1. Shimabukuro (2021) N Engl J Med 384(24):2273-82 +PMID: 33882218
  5. No Vaccine contains fetal cells (social media myth)
  6. None of the Vaccines are associated with Infertility (social media myth)
  7. (2021) Presc Lett 28(4): 19 [PubMed]
  1. Johnson/Johnson-Janssen Vaccine (Ad26.Cov2.S)
    1. Uses Adenovirus vector to introduce cellular RNA
      1. Modified viral vector that is considered harmless (not a Live Vaccine)
    2. Protocol
      1. Initial: Single Intramuscular Injection
      2. Booster: Give at least 2 months after initial dose
        1. Indicated in all patients over age 18 years (due to lower efficacy than the mRNA Vaccines)
    3. Compared with mRNA Vaccines, this Vaccine is far more stable
      1. May be stored in refrigerator for months
    4. Efficacy data is difficult to compare with mRNA Vaccines
      1. This Vaccine was tested after emergence of variant strains (e.g. South Africa)
      2. Efficacy: 60-70% overall (much of which was likely variant strains)
      3. Prevents severe Covid19 (ICU admission or death) in 85%
    5. Adverse Effects
      1. Thrombocytopenia
      2. Venous thrombosis (e.g. Cerebral Venous Thrombosis, splanchnic vein thrombosis)
        1. Rare (50.4 cases in 16.4 million doses)
        2. Atypical thrombosis sites
        3. Seen primarily in women age <50 years, 1-2 weeks after Vaccine
        4. May be autoimmune induced condition similar to HIT and TTP
          1. Heparin Induced Thrombocytopenia (HIT)
          2. Thrombotic Thrombocytopenic Purpura (TTP)
      3. Guillain Barre Syndrome
        1. Rare (268 cases in 16.4 million doses)
        2. Primarily in men (esp. >50 years old)
    6. References
      1. (2021) Presc Lett 28(3): 13
      2. (2021) Presc Lett 28(5): 25
  1. Two mRNA Vaccines (Pfizer, Moderna) released and FDA approved in U.S., December 2020
  2. Expect flu-like symptoms (Fatigue, myalgias), especially after second dose
  3. Both initial U.S. Covid-19 Vaccines are mRNA Vaccines with a unique mechanism
    1. https://berthub.eu/articles/posts/reverse-engineering-source-code-of-the-biontech-pfizer-vaccine/
    2. mRNA is taken up by cells, translated to covid spike protein which is then expelled extracellularly
    3. Antibody forms to COVID-19 spike protein after 2 Vaccine doses spaced 21-28 days apart
    4. The mRNA is fragile and degrades soon after injection, and does NOT affect DNA
  4. Dosing: Adults
    1. Pfizer-BioNTech 30 mcg (0.3 ml/dose) IM given 21 days apart
      1. Must be diluted with 1.8 ml preservative-free saline
      2. Gently invert Vaccine to mix (do not shake)
    2. Moderna 0.5 ml/dose IM (undiluted) given 28 days apart
      1. Gently swirl Vaccine to mix (do not shake)
  5. Dosing: Children (age 5 to 12 years)
    1. Pfizer-BioNTech 10 mcg IM given 21 days apart
  6. Precautions
    1. mRNA Vaccines must be stored at low Temperatures
      1. Pfizer-BioNTech
        1. https://www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/storage-summary.pdf
        2. Initial: -80ºC to -60ºC (-112ºF to -76ºF)
        3. Up to 2 weeks: -25°C to -15°C (-13°F to 5°F)
        4. Up to 5 days at standard refrigerator Temperature
      2. Moderna
        1. https://www.cdc.gov/vaccines/covid-19/info-by-product/moderna/downloads/storage-summary.pdf
        2. Initial: -50°C and -15°C (-58°F and 5°F) for unpunctured vials
        3. Up to 30 days: 2° to 8°C (36° to 46°F) for unpunctured vials
        4. Up to 12 hours: 2°F and 25°C (36°F to 77°F) for punctured vials
    2. Avoid other Vaccines within 14 days (to avoid confusion in reactions, and ensure maximal efficacy)
    3. If more than 50% of dose leaks with injection, give a full dose in opposite arm
    4. Second Vaccine dose may be given up to 4 days before recommended schedule and up to 42 days after
      1. However, give second dose even if >42 days from first dose, and repeating series not recommended
    5. Third Vaccine dose indications
      1. Immunocompromised patients
        1. Third dose (not considered booster) given >28 days from second mRNA Vaccine (Pfizer or Moderna)
      2. Booster Dose (Pfizer or Moderna)
        1. Patients may switch mRNA Vaccines (mix and match approach)
        2. Booster not needed if patient received a third dose due to Immunocompromised state
        3. Booster dose not recommended for ages 5 to 12 years as of fall 2021
        4. Dose
          1. Pfizer: Full dose (0.3 ml)
          2. Moderna: Half dose (0.25 ml) or if unavailable, give full dose
        5. Indications (>6 months after second dose)
          1. Age >65 years old
          2. Longterm care residents
          3. Comorbidity (e.g. Diabetes, Obesity) and age 50 to 64 years (and consider for age 18 to 49 years)
          4. Occupational Exposure (e.g. Healthcare workers, teachers)
          5. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/booster-shot.html
  7. Contraindications
    1. Severe Allergic Reaction to Polyethylene glycol, polysorbate or first Covid Vaccine dose
    2. Severe Allergic Reaction to other injectable medications is not an absolute contraindication
      1. Observe for 30 minutes after Vaccination (typically 15 minutes)
      2. Epinephrine injection should be available
    3. Convalescent Plasma or Covid Monoclonal Antibody in last 90 days
      1. Prevents adequate Vaccine immune response
    4. COVID-19 Infection within last 90 days is not a contraindication to Vaccination
      1. However, repeat infection in subsequent 90 days is unlikely (may delay Vaccine)
  8. Efficacy
    1. Both mRNA Vaccines (Pfizer, Moderna) appear to have 95% effectiveness
    2. However, initial efficacy data preceded emergence of more transmissible variant strains
    3. Immunity appears to wane after dosing, and booster doses recommended in adults as of Fall 2021
    4. mRNA Vaccines are 5 fold more effective than natural Immunity in preventing Covid19 reinfection
  9. Safety
    1. Appears safe in Immunocompromised state, pregnancy, Breastfeeding
    2. Pfizer Vaccine has been FDA approved down to age 5 years and older as of 2021
  10. Adverse Effects
    1. Anaphylaxis
      1. Risk 2-5 per million vaccinated patients
    2. Myocarditis or Pericarditis
      1. Risk 70 per one million males ages 12 to 17 years old
  • Resources
  1. CDC Covid19 Vaccine Adverse Effects
    1. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/adverse-events.html
  • References
  1. (2021) Presc Lett 28(2): 7
  2. (2021) Presc Lett 28(11): 61
  3. (2021) Presc Lett 28(12): 67-8