Key Points

• Poliovirus
  • Member of Picornavirus family
    • Also an enterovirus (closely related to Coxsackievirus)
  • Presentation
    • Poliomyelitis
      • Damages motor neurons of anterior horns of spinal cord
        • Causes LMN disease: flaccid paralysis, atrophy, areflexia, fasciculations
  • Vaccination
    • Live-attenuated oral vaccine (OPV)
      • Also called the Sabin vaccine
      • Stronger IgA response (than Salk)
        • Detected in oropharyngeal and intestinal mucosa
        • Secretory IgA inhibits viral entry at GI mucosa
      • Rare vaccine-associated paralytic poliomyelitis (VAPP)
        • Occurs in 1 in 1 million people vaccinated
        • For this reason, IPV is preferred in developed countries with low polio rates (cost > benefit)
        • In developing countries, OPV is still used due to lower cost and greater efficacy (cost < benefit)
    • Inactivated (Salk) vaccine (IPV)
      • Only IPV is approved for use in USA, since no VAPP risk compared to OPV