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Open Access Research article

Limited duration of vaccine poliovirus and other enterovirus excretion among human immunodeficiency virus infected children in Kenya

Nino Khetsuriani1*, Rita Helfand1, Mark Pallansch1, Olen Kew1, Ashley Fowlkes1, M Steven Oberste1, Peter Tukei2, Joseph Muli2, Ernest Makokha2 and Howard Gary1

Author Affiliations

1 Centers for Disease Control and Prevention, Atlanta, Georgia, USA

2 Kenya Medical Research Institute, Nairobi, Kenya

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BMC Infectious Diseases 2009, 9:136  doi:10.1186/1471-2334-9-136

Published: 23 August 2009

Abstract

Background

Immunodeficient persons with persistent vaccine-related poliovirus infection may serve as a potential reservoir for reintroduction of polioviruses after wild poliovirus eradication, posing a risk of their further circulation in inadequately immunized populations.

Methods

To estimate the potential for vaccine-related poliovirus persistence among HIV-infected persons, we studied poliovirus excretion following vaccination among children at an orphanage in Kenya. For 12 months after national immunization days, we collected serial stool specimens from orphanage residents aged <5 years at enrollment and recorded their HIV status and demographic, clinical, immunological, and immunization data. To detect and characterize isolated polioviruses and non-polio enteroviruses (NPEV), we used viral culture, typing and intratypic differentiation of isolates by PCR, ELISA, and nucleic acid sequencing. Long-term persistence was defined as shedding for ≥ 6 months.

Results

Twenty-four children (15 HIV-infected, 9 HIV-uninfected) were enrolled, and 255 specimens (170 from HIV-infected, 85 from HIV-uninfected) were collected. All HIV-infected children had mildly or moderately symptomatic HIV-disease and moderate-to-severe immunosuppression. Fifteen participants shed vaccine-related polioviruses, and 22 shed NPEV at some point during the study period. Of 46 poliovirus-positive specimens, 31 were from HIV-infected, and 15 from HIV-uninfected children. No participant shed polioviruses for ≥ 6 months. Genomic sequencing of poliovirus isolates did not reveal any genetic evidence of long-term shedding. There was no long-term shedding of NPEV.

Conclusion

The results indicate that mildly to moderately symptomatic HIV-infected children retain the ability to clear enteroviruses, including vaccine-related poliovirus. Larger studies are needed to confirm and generalize these findings.