Covid-19 Vaccine

Aka: Covid-19 Vaccine, Covid19 Immunization, Corona Virus 19 Vaccination, Covid19 Bivalent Vaccine, MSARS-CoV-2 mRNA Vaccine

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II. Background

  1. Encourage Vaccination in all adult patients and in children age >6 months
    1. As of 2024, Covid19 in U.S. still hospitalizes 20,000/week and kills 2000/week
    2. Up-to-date Covid19 Vaccine decreases severe illness risk by up to 50%
    3. Unlike other viruses, Covid19 occurs year round and often spikes in summer
  2. All U.S. Vaccines are considered safe
    1. Patients should get whichever Vaccine is available
    2. Efficacy favors 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]

III. 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)

IV. Medications: 2024-2025 Monovalent mRNA Vaccines

  1. Types: mRNA Monovalent Vaccines for 2024-2025 season (CDC recommends any of the following)
    1. Moderna (targets KP.2 Variant)
    2. Pfizer-BioNTech (targets KP.2 Variant)
    3. Novavax (targets JN.1)
  2. Dosing
    1. See below (similar to prior dosing years)
    2. Approved for 6 months and older

V. Medications: 2023-2024 Monovalent mRNA Covid Vaccine

  1. Types: mRNA Monovalent Vaccines for 2023-24 season
    1. Moderna SpikeVax
    2. Pfizer-BioNTech Comirnaty
  2. Covers Omicron XBB.1.5 SARS-CoV-2
    1. Includes EG.5.1 (Eris) and BA.2.86 (Pirola)
  3. Timing
    1. Initial Dose (available in U.S. starting October 2023)
      1. Continue to encourage Vaccine throughout 2024
      2. Wait at least 2 months after last bivalent Vaccine dose
      3. Wait at least 3 months after Covid Infection
    2. Indications for booster dose (spring of 2024)
      1. Moderate to severe Immunocompromised state age >6 months (and >2 months after last dose)
      2. Moderate risks (>4 months after last dose)
        1. Age >65 years (esp. age >75 years)
        2. Long term care resident
        3. Significant Chronic Disease (heart disease, Diabetes Mellitus)
      3. References
        1. (2024) Presc Lett 31(4): 19
  4. Dosing
    1. Age 6 months to 5 years (no prior covid Vaccine)
      1. Give 2 Moderna or 3 Pfizer scheduled doses with at least one dose using the 2023-24 Vaccine
    2. Age 5 years and older
      1. Give 1 dose regardless of prior covid Vaccination
    3. Moderate to Severe Immunocompromised State
      1. Give 3 scheduled doses with at least one dose using the 2023-24 Vaccine
  5. Cost
    1. Covid Vaccine costs ($120-130/dose) are no longer government funded in U.S.
    2. However, most insurance is expected to cover majority of Vaccination cost
  6. References
    1. (2023) Presc Lett 30(10): 55

VI. Medications: 2022 Bivalent MSARS-CoV-2 mRNA Vaccines

  1. Background
    1. As of October 2023, replaced by the Omicron variant Vaccine (see above)
    2. Originally used for booster dose, and then replaced the monovalent Vaccine for all doses
    3. As of June 2023, only 17% of U.S. population has had a bivalent dose
    4. Associated with better and longer efficacy than the original monovalent Vaccine, and fewer emergency department visits
  2. Pfizer or Moderna
    1. Patients may switch mRNA Vaccines (mix and match approach)
    2. Bivalent Covid Vaccine (original Covid strain + two Omicron strains)
      1. Available as of fall 2022 and replaces all prior mRNA booster Vaccinations
    3. Bivalent Covid Dose
      1. Pfizer: Full dose (0.3 ml)
      2. Moderna: Full dose (0.5 ml)
        1. Prior Moderna monovalent boosters were half dose (0.25 ml)
    4. Boosters
      1. Requires 2 prior doses of primary Covid Vaccine
      2. May give at least 2 months after last Covid Vaccine dose (typically 3 to 6 months from last dose)
      3. As of 2022, only one bivalent Vaccine dose is recommended for most patients (may morph into annual Vaccination)
        1. A second booster dose is being offered as of 2023 to patients over age 65 years
      4. Initially booster doses were limited to high risk populations, but are now recommended for everyone (over minimum age)
        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

VII. Medications: 2021 Monovalent MSARS-CoV-2 mRNA Vaccines

  1. Original Covid Vaccines replaced by newer agents
  2. Two mRNA Vaccines (Pfizer, Moderna) released and FDA approved in U.S., December 2020
  3. Expect flu-like symptoms (Fatigue, myalgias), especially after second dose
  4. 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
  5. 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)
  6. Dosing: Children (age >6 months as of 2022)
    1. Three to four dose Vaccination schedules (monovalent and bivalent) are approved for age >6 months
    2. Schedules vary based on manufacturer
  7. 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. Booster Vaccine doses
      1. Immunocompromised patients
        1. Third dose (not considered booster) given >28 days from second mRNA Vaccine (Pfizer or Moderna)

VIII. 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

IX. Safety

  1. Appears safe in Immunocompromised state, pregnancy, Breastfeeding
  2. Pfizer Vaccine has been FDA approved down to age 6 months and older as of 2022

X. Adverse Effects

  1. Anaphylaxis
    1. Risk 2-5 per million vaccinated patients
  2. Myocarditis or Pericarditis
    1. Pericarditis or Myocarditis was associated with BNT162b2 and mRNA-1273 Vaccines
    2. Incidence has been low (<2 per 100,000), even in the highest risk groups (young males age 18 to 25 years)
      1. Incidence initially reported as high as 70 per one million males ages 12 to 17 years old
    3. References
      1. Lane (2022) BMJ Open 12(5): e059223 [PubMed]
      2. Wong (2022) Lancet 399(10342): 2191-9 [PubMed]
      3. Abraham (2022) Vaccine 40(32): 4663-71 [PubMed]

XI. Preparations: Other non-mRNA Vaccines

  1. Protein Subunit Vaccine (NVX-CoV2373, Novavax)
    1. New covid Vaccine available as of 2022
    2. Efficacy data against Omicron still pending as of early 2023
    3. Given as 2 doses separated by 3 to 8 weeks (3 weeks if Immunocompromised)
    4. Contains SARS-CoV2 Spike glyoprotein and adjuvant matrix-M
  2. Johnson/Johnson-Janssen Vaccine (Ad26.Cov2.S)
    1. SARS-CoV-2 Viral Vector Vaccine
    2. mRNA Vaccines are preferred
    3. Uses Adenovirus vector to introduce cellular RNA
      1. Modified viral vector that is considered harmless (not a Live Vaccine)
    4. 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)
    5. Compared with mRNA Vaccines, this Vaccine is far more stable
      1. May be stored in refrigerator for months
    6. 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%
    7. 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)
    8. References
      1. (2021) Presc Lett 28(3): 13
      2. (2021) Presc Lett 28(5): 25

XII. Resources

  1. CDC Covid19 Vaccine Adverse Effects
    1. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/adverse-events.html

XIII. References

  1. (2024) Presc Lett 31(9): 49
  2. (2023) Presc Lett 30(6): 31
  3. (2022) Presc Lett 29(10): 55-6
  4. (2021) Presc Lett 28(2): 7
  5. (2021) Presc Lett 28(11): 61
  6. (2021) Presc Lett 28(12): 67-8

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