Vaccine-Derived Poliovirus Infections in an Amish Population Minnesota, 2005

1. Vaccine-Derived Poliovirus Infections in an Amish PopulationMinnesota, 2005 Harry F. Hull, M.D. State Epidemiologist Minnesota Department of Health

2. Index Patient • Sept 29 – Poliovirus type 1 identified in stool sample • Unvaccinated, immunocompromised 7 m Amish girl • No paralysis • Recurring fevers, Outpatient Antibiotic Rx • Pneumonia, community hospital July • Continuously hospitalized since August 22 • Regional Medical Center, Children’s Hospital, University Hospital • Failure to thrive, diarrhea, recurrent infections • Contact precautions beginning August 30 • Diagnosed Severe Combined Immunodeficiency Sept 15 • Enterovirus isolated from stool collected Aug 27 • Rx high PV1 titre IVIG with assistance from FDA • Still shedding after failed Bone Marrow Transplant

4. Epidemiological Investigation • Born at home • 3 unvaccinated siblings < 5 yrs • Parents and some elders vaccinated 1979 • Travel to visit grandparents in Wisconsin – 3 mo • Visitors from Amish Communities in MN, WI, MI, Ontario including large weddings • No community members with travel outside North America

5. Epidemiological Investigation • No known immunodeficient persons in MN Amish communities • No immunodeficient persons on staff of hospitals • No international immunodeficient persons of appropriate age in medical facilities in MN • No international VAPP in Shriner’s hospitals

6. Virological Investigation • 2.3% divergent from Sabin 1 • Clusters with iVDPV • Initially thought to arise from a healthcare source • Subsequent data suggest circulation in the community prior to index case’s infection

8. Virological Investigation • 3/3 siblings • All anti-PV1 +, negative anti-PV2, anti PV3 • Stool cultures negative • Stool samples collected 32 persons/5 households • 4 well children ages 2-14 yrs in 2 households shedding virus • Minimal contact with index household • 30 HCWs and 35 patients culture neg at Hospital 4

9. Index Family

10. Immunization • IPV was offered to • community members • All MN Amish communities • Non-Amish community members • Many elders vaccinated in 1979 • IPV offered to staff and patients at Hospital 4

11. Immunization • 9 out of 24 families in index community • 31 out of 32 Amish families in nearby community which requested vaccination • 9 out of 11 Amish families in another nearby community where vaccine was offered • Another nearby Amish community refused • Other MN Amish communities • 35% to 100% initiated IPV • 135 staff vaccinated Hospital 4

12. Disease Surveillance • AFP surveillance initiated for potential adverse reactions to Menactra • 9 GBS in 3 years in 4 Amish counties • All 4 GBS in 2005 >45 years • No Amish with GBS/polio • Aseptic meningitis in Amish counties • No Amish with aseptic meningits • No illness compatible with polio in HCWs or patients at all 4 hospitals • National and international notifications

13. Conclusions • 29th known chronically infected immunodeficient poliovirus excreter • Origin unknown, probably chronically infected immunodeficient #30 overseas • Virus circulated in community • Index case infected in community • No evidence of circulation beyond MN Amish

14. Concerns • Prevalence of chronic VDPV infection unknown • iVPDV transmitted person-to-person • Optimum strategy for control unclear • IPV coverage incomplete • Virus circulating for weeks before campaign • Silent transmission, no neurologic disease • Will BMT clear infection? • Stopping vaccination after polio eradicated