OPV Vaccination Series - Historical Context
Critical Update: OPV is No Longer Used in the United States
Oral poliovirus vaccine (OPV) has been replaced by inactivated poliovirus vaccine (IPV) in the United States and most developed countries due to the risk of vaccine-associated paralytic poliomyelitis (VAPP). The all-IPV schedule is now the standard of care. 1, 2, 3
Historical OPV Schedule (No Longer Recommended in U.S.)
For historical reference, the OPV series that was used until the late 1990s consisted of:
- First dose: 6-8 weeks of age 1
- Second dose: Approximately 2 months after the first dose 1
- Third dose: 6 months of age (recommended in 1995 to improve completion rates, though 6-18 months remained acceptable) 1
- Fourth dose: 4-6 years of age 1
The rationale for the third dose at 6 months was that seroconversion rates of 96-100% were achieved regardless of whether the third dose was given at 6,12, or 18 months, but earlier administration ensured higher completion rates. 1
Current Standard: IPV Schedule
The recommended childhood polio vaccination schedule now consists of 4 doses of IPV administered at ages 2 months, 4 months, 6-18 months, and 4-6 years. 1, 2, 3
Key Timing Requirements:
- Minimum intervals: 4 weeks between doses 1-2,4 weeks between doses 2-3, and 6 months between doses 3-4 3
- Final dose requirement: Must be administered at age ≥4 years regardless of number of previous doses 2, 3
- No series restart needed: If the schedule is interrupted, continue where you left off without restarting 2, 3
Why IPV Replaced OPV:
- VAPP risk eliminated: OPV carried a risk of 1 case per 750,000 first doses and 1 per 2.4 million overall doses 4
- Equivalent protection: IPV provides excellent immunity with seroprotection rates of 98-100% after 3 doses 5
- Safety profile: IPV is well-tolerated with no serious adverse events 3
Special Circumstances
OPV should not be administered to HIV-infected persons or their household contacts. 1 This is a critical safety consideration given the live-attenuated nature of OPV.