Table 1.

4:3:1:3:3:1:4 Vaccine Series^* Coverage for Children 19 to 35 Months of Age by Participation Policy Type

IIS Participation Policy Type	No. of Jurisdictions	4:3:1:3:3:1:4 Vaccine Series Coverage For 19–35 Months of Age (%)	Median 4:3:1:3:3:1:4 Vaccine Series Coverage For 19–35 Months of Age (%)
Mandatory participation with no opt out option	12	18–88	67
Mandatory participation with opt out option	2	46, 70	58
Implicit consent to participate with opt out option	45	9–77	62
Opt in participation only	4	41–75	56
N/A— No IIS	1	–	–

IIS indicates immunization information systems.

^*4:3:1:3:3:1:4 vaccine series refers to: 4 doses of Diphtheria, Tetanus, and Pertussis (DtaP), ≥3 doses of poliovirus vaccine, ≥1 dose of measles-containing vaccine, the full series of Haemophilus influenzae type b vaccine (Hib–≥3 or ≥4 doses, depending on product type), ≥3 doses of Hepatitis B (HepB) vaccine, ≥1 dose of varicella vaccine, and ≥4 doses of Pneumococcal (PCV) vaccine.