US Childhood Vaccine Schedule

A century of evolution from 1920s to 2020s

11 Decades ~30 Doses Today 11+ Vaccine Types

1920s

Primary: ~1-2 Boosters: 0-1 Total Doses: ~1-3

Existing Vaccines

Starting point - no prior routine schedule

Newly Added

  • Smallpox - common in many areas
  • Diphtheria - toxoid/antitoxin-era prevention

Why: Big outbreaks, high mortality

Fatality Rate

Smallpox: ~30% CFR (unvaccinated)

"Required" Reality

Often smallpox for school; not universal

Controversies

  • Anti-vaccination leagues (since 1800s)
  • Jacobson v. Massachusetts (1905)

1930s

Primary: ~2-4 Boosters: 0-1 Total Doses: ~2-5

Existing Vaccines

  • Smallpox
  • Diphtheria toxoid

Newly Added

  • Tetanus toxoid development
  • Pertussis - not yet uniformly routine

Fatality Rate

Diphtheria: ~5-10% overall (higher in kids)

"Required" Reality

Still patchwork; primarily smallpox where school-entry laws existed

Controversies

Lubeck disaster (1930) - 72 infant deaths

1940s

Primary: ~3-5 Boosters: 1-3 Total Doses: ~4-8

Existing Vaccines

  • Smallpox
  • Diphtheria, Tetanus, Pertussis (separate)

Newly Added (Major Step)

Combined DTP - single vaccine replaces 3

Fatality Rates

Pertussis: Infants highest risk
Tetanus: ~1 in 10 cases

"Required" Reality

Still not uniform across states

Controversies

Early pertussis vaccines had high reactogenicity

1950s

Primary: ~6-9 Boosters: 2-4 Total Doses: ~8-13

Existing Vaccines

  • Smallpox
  • DTP (routine series)

Newly Added

Polio vaccine begins mid-1950s (IPV, then OPV)

Fatality Rate

Polio: ~2-5% CFR; bulbar far higher

"Required" Reality

Not universal - by 1963 only 20 states had requirements

Controversies

  • Cutter Incident (1955) - 40,000 cases
  • SV40 contamination

1960s

Primary: ~7-11 Boosters: 2-4 Total Doses: ~9-15

Existing Vaccines

  • DTP
  • Polio (expands with OPV)
  • Smallpox

Newly Added

  • Measles (licensed 1963)
  • Mumps (late 1960s)
  • Rubella (late 1960s)

Fatality Rate

Measles: ~1-3 per 1,000 infections

"Required" Reality

17 states by 1969 - not uniform

Controversies

  • Early measles vaccine withdrawn
  • Vaccine-derived polio concerns

1970s

Primary: ~8-12 Boosters: 3-5 Total Doses: ~11-17

Existing Vaccines

  • DTP, Polio
  • Measles, Mumps, Rubella (separate)

Ended: Routine smallpox

Newly Added

Combined MMR (1971) - replaces 3 shots

Fatality Rates

Measles: ~0.1-0.3%
Rubella: Fetal loss/defects

"Required" Reality

Expanding rapidly toward all states by 1980

Controversies

  • 1976 Swine Flu - GBS link
  • DTP lawsuits begin

1980s

Primary: ~10-16 Boosters: 3-6 Total Doses: ~13-22

Existing Vaccines

  • DTP/DTaP
  • Polio, MMR

Newly Added

  • Hib - recommended 1989
  • 2nd MMR dose late decade

Fatality Rate

Hib: ~3-6% CFR; 15-30% neurologic sequelae

"Required" Reality

By 1980: All 50 states have measles school laws

Controversies

  • "Vaccine Roulette" (1982)
  • NCVIA (1986) - vaccine court

1990s

Primary: ~16-22 Boosters: 5-8 Total Doses: ~21-30

Existing Vaccines

  • DTP -> DTaP (late 1990s)
  • Polio, MMR (2 doses), Hib

Newly Added

  • Hepatitis B - universal infant (1991)
  • Varicella - mid-1990s

Fatality Rates

Hib: 3-6%
Varicella: ~1 per 100,000

"Required" Reality

HepB and varicella roll into mandates - not universal

Controversies

  • Wakefield (1998) - fraudulent study
  • Gulf War Syndrome blamed

2000s

Primary: ~20-27 Boosters: 6-10 Total Doses: ~26-37

Existing Vaccines

  • DTaP, Polio (IPV), MMR, Hib
  • Hepatitis B, Varicella

Newly Added

  • PCV, Hepatitis A, Rotavirus
  • Tdap, HPV, MenACWY

Fatality Rates

PCV: ~10% CFR
HPV: ~4,000 cancer deaths/yr

"Required" Reality

Varicella widespread; Tdap for middle school - varies by state

Controversies

  • Thimerosal removed (2001)
  • "Too many too soon"

2010s

Primary: ~22-29 Boosters: 7-12 Total Doses: ~29-41

Existing Vaccines (11 types)

  • DTaP/Tdap, IPV, MMR, Hib, HepB
  • Varicella, PCV, HepA, Rotavirus
  • HPV, MenACWY

Strengthened

  • MenACWY booster approach
  • HPV shifts to 2-dose

Meningococcal

10-15% CFR; amputations/hearing loss

"Required" Reality

Most states: Tdap + MenACWY for middle school

Controversies

  • Disneyland outbreak (2014)
  • CA SB277 (2015)
  • "VAXXED" documentary

2020s

Primary: ~22-28 Boosters: 7-10 Total Doses: ~29-38

Existing Vaccines (11 types)

  • DTaP/Tdap, IPV, MMR, Hib, HepB
  • Varicella, PCV, HepA, Rotavirus
  • HPV (2-3 doses), MenACWY (+booster)

Status (Excl. Flu/COVID)

  • No brand-new disease targets
  • Ongoing schedule tweaks

"Required" Reality

Core near-universal K-12: DTaP/Tdap, IPV, MMR, Varicella, HepB

Dec 2025: CDC shifted away from universal HepB birth dose for HepB-negative mothers

Controversies

  • COVID vaccine mandates - massive backlash
  • mRNA technology distrust
  • "Vaccine passport" debates
  • RFK Jr. gains attention