Vaccine policy changes and epidemiology of poliomyelitis in the United States.
Level 4 - case-series / case-control
National surveillance registry review and historically controlled policy time-trend analysis
PubMed 15479934 · doi:10.1001/jama.292.14.1696
What was done
Researchers reviewed national US surveillance data from 1990 through 2003 to assess confirmed paralytic poliomyelitis cases and evaluate the impact of shifting national vaccination schedules: from oral poliovirus vaccine (OPV) prior to 1997, to a sequential inactivated poliovirus vaccine (IPV)-OPV schedule in 1997–1999, to an exclusive IPV schedule adopted in 2000.
What was found
From 1990 through 1999, 61 confirmed paralytic poliomyelitis cases were reported: 59 (97%) were vaccine-associated paralytic poliomyelitis (VAPP; rate of 1 case per 2.9 million OPV doses distributed), 1 was imported (in 1993), and 1 was indeterminate. During the 1997–1999 transition, 13 VAPP cases occurred, all associated with the all-OPV schedule and zero with the sequential IPV-OPV schedule. Following the switch to an exclusive IPV schedule in 2000, zero cases of paralytic poliomyelitis or VAPP were reported through 2003 (the last US VAPP case occurred in 1999).
Why it matters
This evaluation documented that shifting entirely to inactivated poliovirus vaccine eliminated domestic vaccine-induced paralysis without allowing wild or imported poliovirus circulation to re-emerge.
Limits
Findings rely on national surveillance systems, which carry potential risk of underreporting mild or unconfirmed cases. The analysis reflects US-specific epidemiological conditions where wild-type poliovirus transmission had already ceased, meaning findings may not directly generalize to regions with active wild poliovirus transmission.
Cited by
- supports The United States stopped using the live oral polio vaccine because it caused more cases of polio than wild poliovirus, which has not caused a case in the US for a long time.