Vaccines: Risks and Benefits

A Summary of the Evidence

Disease Complications of Natural Infection Benefits of the Vaccine Risks of the Vaccine
Measles, Mumps, and Rubella (MMR)
  • Measles:
    • 1 in 1,000 chance of brain swelling (encephalitis)
    • 1-2 in 1,000 risk of death
    • Lifelong immune suppression
  • Mumps:
    • 1 in 10 risk of meningitis
    • 1 in 20,000 risk of permanent deafness
    • Infertility in males (rare)
  • Rubella:
    • 90% risk of birth defects if infected during pregnancy
    • Miscarriage risk
  • 97% effective at preventing measles with two doses
  • 88% effective at preventing mumps
  • Highly effective at preventing rubella and associated birth defects
  • Mild fever or rash possible
  • 1 in 3,000 risk of febrile seizures (benign)
  • 1 in 30,000 risk of temporary low platelets (ITP)
  • 1 in 1 million risk of severe allergic reaction (anaphylaxis, treatable)
COVID-19
  • Long COVID (10-30% of cases)
  • Myocarditis risk is 2-5x higher than risk from vaccine
  • Hospitalization: 1 in 5 unvaccinated adults over 50
  • Death: 1 in 100 for high-risk individuals
  • 90%+ protection against severe illness and hospitalization
  • 1 in 50,000 risk of myocarditis in young males (86% lower risk than unvaccinated viral illness)
  • 1 in 1 million risk of severe allergic reaction
Flu (Influenza)
  • 200,000 hospitalizations per year in the U.S.
  • 1 in 1,000 risk of death in high-risk individuals
  • Reduces flu-related hospitalizations and deaths
  • Protects vulnerable populations
  • Soreness at injection site (common)
  • Mild fever or muscle aches (rare)
  • 1 in 1 million risk of Guillain-Barré syndrome, severe allergic reaction
Chickenpox (Varicella)
  • Can lead to shingles later in life
  • 0.85 in 100,000 children develop severe complications like skin infections, pneumonia, neurologic disorders (e.g. brain swelling) requiring hospitalization
  • Prevents chickenpox and future risk of shingles
  • 1 in 20 chance of mild rash
  • 1 in 1 million risk of severe allergic reaction
Shingles
  • 1 in 5 persons above 50 years old will develop shingles over 20 year period. Risk increase with age
  • Severe nerve pain (postherpetic neuralgia), can last for months to years
  • 10-20% of cases cause long-term complications
  • Over 90% effective at preventing shingles and long-term nerve pain
  • Temporary sore arm, fatigue (common)
  • 1 in 100,000 risk of severe allergic reaction
HPV (Human Papillomavirus)
  • Can cause cervical, throat, anal, and genital cancers
    • Women: 1 in 20 lifetime risk
    • Men: 1 in 30 lifetime risk
  • Approximately 1 in 100 sexually active adults develop persistent HPV infection leading to cancer
  • Prevents over 90% of HPV-related cancers
  • Temporary soreness at the injection site (common)
  • 1 in 1 million risk of severe allergic reaction
Tetanus
  • Causes severe muscle spasms, difficulty breathing
  • Prior to vaccine, lifetime risk of 1 in 6,000 of acquiring tetanus
  • Fatal in 1 of 3 cases even with treatment
  • 97% preventable with vaccination
  • Mild arm pain, fatigue for 1-2 days (common)
  • 1 in 1 million risk of severe allergic reaction
Whooping Cough (Pertussis)
  • Severe coughing fits can last weeks to months
  • Can cause pneumonia, seizures, or brain damage in infants
  • 1 in 23 of those unvaccinated become ill over 10 year period
  • 1 in 100 infants become ill during outbreaks (unable to vaccinate until 6 months)
  • Fatal in 1 in 100 infants
  • 95% effective at preventing whooping cough, especially in infants
  • Parents vaccinating themselves cuts their infant’s risk of whooping cough in 1/2.
  • Maternal vaccination during pregnancy reduces infant’s risk by up to 90%
  • Soreness at the injection site (common)
  • Mild fever, fatigue (rare)
  • 1 in 1 million risk of severe allergic reaction
Pneumonia (Pneumococcal Disease)
  • 1.5 million hospitalizations per year in the U.S.
  • 1 in 20 risk of death in adults over 65
  • Can cause meningitis and bloodstream infections
  • Reduces risk of pneumonia, meningitis, and bloodstream infections
  • 30% reduction in children under 5 years, resulting up to 700,000 less hospitalized children every year in the United States (new PCV20 vaccine suspected to exceed these numbers)
  • 75% reduction in invasive pneumococcal disease in older adults
  • Soreness at the injection site (common)
  • Mild fever, muscle aches (rare)
  • 1 in 1 million risk of severe allergic reaction
Hepatitis B
  • 90% of infants and 5-10% of adults develop chronic infection
  • Can cause liver failure or liver cancer
  • Prevents liver cancer and chronic liver disease
  • Soreness at the injection site (common)
  • Mild fever, fatigue (rare)
  • 1 in 1 million risk of severe allergic reaction
Meningitis (Meningococcal Disease)
  • 10-15% of cases are fatal, even with treatment
  • 1 in 5 survivors have brain damage, amputations, or hearing loss
  • Prevents meningitis outbreaks
  • Protects against deadly bacterial infections with up to 83% efficacy in children
  • Soreness at the injection site (common)
  • 1 in 1 million risk of severe allergic reaction

Notes: Of the 1 in 1,000,000 that experience anaphylaxis from vaccination, 98% are treated with no long-term harm.

References
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