mlk_man
11-08-2005, 12:37 PM
Poliovirus Infections in Four Unvaccinated Children --- Minnesota, August--October 2005
Posted 10/31/2005http://images.medscape.com/pi/global/ornaments/spacer.gif
Content
On October 14, this report was posted as an MMWR Dispatch on the MMWR website (http://www.cdc.gov/mmwr (http://www.cdc.gov/mmwr)).
On September 29, 2005, the Minnesota Department of Health (MDH) identified poliovirus type 1 in an unvaccinated, immunocompromised infant girl aged 7 months (the index patient) in an Amish community whose members predominantly were unvaccinated for polio. The patient has no paralysis; the source of the patient's infection is unknown. Subsequently, poliovirus infections in three other children within the index patient's community have been documented. This report summarizes the ongoing investigation, provides information regarding poliovirus exposure risks and prevention measures in the United States, and offers recommendations to state health departments and clinicians.
Index Case Summary
The index patient was first admitted to a community hospital in central Minnesota for pneumonia in July 2005. Since August 22, this infant has been hospitalized continuously at three additional hospitals with failure to thrive, diarrhea, and recurrent infections. The infant was placed in strict isolation, and a diagnosis of severe combined immunodeficiency (SCID) was made on September 15. The infant is being clinically managed with intravenous immunoglobulin therapy and is being evaluated for bone marrow transplantation.
Laboratory Investigation
An enterovirus isolate from a stool specimen obtained on August 27, 2005, tested positive for a type 1 poliovirus at the MDH laboratory. Partial sequencing of the virus capsid protein coding region (VP1) of the poliovirus genome at the MDH laboratory identified it as a vaccine-derived poliovirus (VDPV). VDPVs are poliovirus strains derived from one of the three Sabin poliovirus strains in oral polio vaccine (OPV) that have ≥1% difference in nucleotide sequence from the prototype vaccine virus.[1] Additional sequencing of the entire poliovirus genome at the CDC polio laboratory confirmed that this strain was a VDPV, with 2.3% divergence in the VP1 region from the parent Sabin type 1 strain. The viral genome demonstrates no recombination with other polioviruses or species C enteroviruses. Prospective serial stool samples from the infant are being tested to monitor ongoing infection and further mutations in the virus.
Epidemiologic Investigation
Because viral genomic data suggest this poliovirus might have been transmitted to the index patient from another immunocompromised person, the initial investigation focused on identifying immunodeficient persons among community contacts, health-care workers, and patients with whom the infant had potential contact before the first positive poliovirus culture on August 27. Staff and patient records at the hospitals are being reviewed, and inquiries are being made with community members and health-care providers.
Investigations also are under way at the four hospitals where the infant has been treated to determine whether nosocomial transmission from the infant has occurred. At the hospital where the infant currently is a patient, health-care workers and other staff members who have had exposure (without protection from contact precautions) to the infant or the infant's environment are being surveyed regarding polio vaccination status, immune status, and recent relevant illnesses in themselves and their family members. Stool samples are being obtained for viral cultures. Vaccination with inactivated polio vaccine (IPV) is being offered to health-care workers who might have been exposed or who have an ongoing risk for exposure and whose polio vaccination status is not up to date or is unknown. Stool specimens also are being obtained from potentially exposed patients at the hospital where the infant currently is a patient. At the first three hospitals where the infant was admitted, health-care workers are being surveyed regarding immune status and recent illness in themselves or their family members.
To examine community transmission of poliovirus, family members and others in the index patient's community are being surveyed regarding polio vaccination status, immune status, and recent illnesses. To date, stool samples have been collected from 32 persons in five of 24 households, and serum samples have been obtained from eight persons in three households, including the index patient's household. Poliovirus type 1 has been confirmed in three of 32 stool specimens; partial sequencing of the VP1 region of these three isolates has indicated they also are VDPV type 1. The positive specimens were obtained from three unvaccinated siblings in one household (not the infant's household). None of these three children have been ill recently, and none were immunocompromised. Stool and serum samples are being requested from additional members of the community. Extended family members and community contacts from other areas who might have come into contact with the index patient are being identified and monitored for illness. IPV is being offered to community members who are not fully vaccinated for polio or whose polio vaccination status is unknown. Hospitals that serve this community and similar communities are being contacted, and retrospective and prospective surveillance is identifying patients whose diagnoses indicate conditions that are clinically consistent with poliovirus infection, including acute flaccid paralysis (AFP), Guillain-Barré Syndrome (GBS), transverse myelitis, and viral or aseptic meningitis.
Reported by:L Bahta, J Bartkus, PhD, J Besser, MS, N Crouch, PhD, E Cebelinski, K Ehresmann, MPH, S Fuller, K Harriman PhD, J Harper, MS, H Hull, MD, R Lynfield, MD, C Miller, MS, J Rainbow, MPH, M Sullivan, MPH, G Wax, MPH, Minnesota Dept of Health; P Ackerman, Children's Hospital and Clinics of Minnesota, Minneapolis. Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Epidemiology and Surveillance Div, National Immunization Program; A Parker, MSN, MPH, EIS Officer, CDC.
Posted 10/31/2005http://images.medscape.com/pi/global/ornaments/spacer.gif
Content
On October 14, this report was posted as an MMWR Dispatch on the MMWR website (http://www.cdc.gov/mmwr (http://www.cdc.gov/mmwr)).
On September 29, 2005, the Minnesota Department of Health (MDH) identified poliovirus type 1 in an unvaccinated, immunocompromised infant girl aged 7 months (the index patient) in an Amish community whose members predominantly were unvaccinated for polio. The patient has no paralysis; the source of the patient's infection is unknown. Subsequently, poliovirus infections in three other children within the index patient's community have been documented. This report summarizes the ongoing investigation, provides information regarding poliovirus exposure risks and prevention measures in the United States, and offers recommendations to state health departments and clinicians.
Index Case Summary
The index patient was first admitted to a community hospital in central Minnesota for pneumonia in July 2005. Since August 22, this infant has been hospitalized continuously at three additional hospitals with failure to thrive, diarrhea, and recurrent infections. The infant was placed in strict isolation, and a diagnosis of severe combined immunodeficiency (SCID) was made on September 15. The infant is being clinically managed with intravenous immunoglobulin therapy and is being evaluated for bone marrow transplantation.
Laboratory Investigation
An enterovirus isolate from a stool specimen obtained on August 27, 2005, tested positive for a type 1 poliovirus at the MDH laboratory. Partial sequencing of the virus capsid protein coding region (VP1) of the poliovirus genome at the MDH laboratory identified it as a vaccine-derived poliovirus (VDPV). VDPVs are poliovirus strains derived from one of the three Sabin poliovirus strains in oral polio vaccine (OPV) that have ≥1% difference in nucleotide sequence from the prototype vaccine virus.[1] Additional sequencing of the entire poliovirus genome at the CDC polio laboratory confirmed that this strain was a VDPV, with 2.3% divergence in the VP1 region from the parent Sabin type 1 strain. The viral genome demonstrates no recombination with other polioviruses or species C enteroviruses. Prospective serial stool samples from the infant are being tested to monitor ongoing infection and further mutations in the virus.
Epidemiologic Investigation
Because viral genomic data suggest this poliovirus might have been transmitted to the index patient from another immunocompromised person, the initial investigation focused on identifying immunodeficient persons among community contacts, health-care workers, and patients with whom the infant had potential contact before the first positive poliovirus culture on August 27. Staff and patient records at the hospitals are being reviewed, and inquiries are being made with community members and health-care providers.
Investigations also are under way at the four hospitals where the infant has been treated to determine whether nosocomial transmission from the infant has occurred. At the hospital where the infant currently is a patient, health-care workers and other staff members who have had exposure (without protection from contact precautions) to the infant or the infant's environment are being surveyed regarding polio vaccination status, immune status, and recent relevant illnesses in themselves and their family members. Stool samples are being obtained for viral cultures. Vaccination with inactivated polio vaccine (IPV) is being offered to health-care workers who might have been exposed or who have an ongoing risk for exposure and whose polio vaccination status is not up to date or is unknown. Stool specimens also are being obtained from potentially exposed patients at the hospital where the infant currently is a patient. At the first three hospitals where the infant was admitted, health-care workers are being surveyed regarding immune status and recent illness in themselves or their family members.
To examine community transmission of poliovirus, family members and others in the index patient's community are being surveyed regarding polio vaccination status, immune status, and recent illnesses. To date, stool samples have been collected from 32 persons in five of 24 households, and serum samples have been obtained from eight persons in three households, including the index patient's household. Poliovirus type 1 has been confirmed in three of 32 stool specimens; partial sequencing of the VP1 region of these three isolates has indicated they also are VDPV type 1. The positive specimens were obtained from three unvaccinated siblings in one household (not the infant's household). None of these three children have been ill recently, and none were immunocompromised. Stool and serum samples are being requested from additional members of the community. Extended family members and community contacts from other areas who might have come into contact with the index patient are being identified and monitored for illness. IPV is being offered to community members who are not fully vaccinated for polio or whose polio vaccination status is unknown. Hospitals that serve this community and similar communities are being contacted, and retrospective and prospective surveillance is identifying patients whose diagnoses indicate conditions that are clinically consistent with poliovirus infection, including acute flaccid paralysis (AFP), Guillain-Barré Syndrome (GBS), transverse myelitis, and viral or aseptic meningitis.
Reported by:L Bahta, J Bartkus, PhD, J Besser, MS, N Crouch, PhD, E Cebelinski, K Ehresmann, MPH, S Fuller, K Harriman PhD, J Harper, MS, H Hull, MD, R Lynfield, MD, C Miller, MS, J Rainbow, MPH, M Sullivan, MPH, G Wax, MPH, Minnesota Dept of Health; P Ackerman, Children's Hospital and Clinics of Minnesota, Minneapolis. Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Epidemiology and Surveillance Div, National Immunization Program; A Parker, MSN, MPH, EIS Officer, CDC.