Oral polio

J Infect Dis. 2004 Apr 1;189(7):1168-75. Epub 2004 Mar 16. Related Articles,
Isolation and characterization of circulating type 1 vaccine-derived poliovirus from sewage and stream waters in hispaniola.

Vinje J, Gregoricus N, Martin J, Gary HE Jr, Caceres VM, Venczel L, Macadam A, Dobbins JG, Burns C, Wait D, Ko G, Landaverde M, Kew O, Sobsey MD.

Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina, Chapel Hill, North Carolina, USA.

Twenty-one cases of acute flaccid paralysis (AFP) were reported on the island of Hispaniola in 2000. Laboratory analysis confirmed the presence of circulating vaccine-derived poliovirus (cVDPV) type 1 in stool samples obtained from patients. As a complement to the active search for cases of AFP, environmental sampling was conducted during November and December 2000, to test for cVDPV in
sewage, streams, canals, and public latrines. Fifty-five environmental samples were obtained and analyzed for the presence of polioviruses by use of cell culture followed by neutralization and reverse-transcription polymerase chain reaction. Of the 23 positive samples, 10 tested positive for poliovirus type 1, 7 tested positive for poliovirus type 2, 5 tested positive for poliovirus type 3, and 1 tested positive for both poliovirus type 2 and type 3. By sequence analysis of the complete viral capsid gene 1 (VP1), a 2.1%-3.7% genetic sequence difference between 7 type 1 strains and Sabin type 1 vaccine strain was found. Phylogenetic analysis showed that these viruses are highly related to cVDPV isolated from clinical cases and form distinct subclusters related to geographic region. Our findings demonstrate a useful role for environmental surveillance of neurovirulent polioviruses in the overall polio eradication program.

PMID: 15031784 [PubMed - in process]


Vaccine-derived polio virus suspected in Minnesota death
Health officials are monitoring health care workers who came into contact with a Minnesota resident who died last month with symptoms including paralytic poliomyelitis.

The Minnesota Department of Health emphasized that the patient had multiple health conditions and a weakened immune system. Although officials are unable to corroborate to what extent polio contributed to the patient’s death, they have confirmed that the infecting virus strain was identical to a strain in the oral poliovirus vaccine.

“This is a very rare occurrence and does not signal a resurgence of polio,” Ruth Lynfield, MD, Minnesota State Epidemiologist said in a press release. Health officials have not yet released details on the patient.

Live-virus oral poliovirus vaccine administration was discontinued in the U.S. nine years ago, due to concerns that vaccine-derived polio strains could spread in rare instances when an unvaccinated or immunodeficient person comes in contact with a vaccinated individual who is shedding the virus.

The injected polio vaccine currently in use contains only inactivated virus.

Since 2000, this is the second polio infection caused by a vaccine strain in the United States, and one of 45 cases reported worldwide since 1961. The last U.S. case of naturally occurring paralytic polio disease occurred in 1979.

“Only unvaccinated people or people with deficient immune systems who have had direct, ungloved contact with the patient’s bodily secretions are at any risk for disease,” Aaron DeVries, MD, medical epidemiologist with the Minnesota Department of Health said. – by Nicole Blazek

This brief report raises a multitude of questions. One wonders first what the vaccination status of this patient was. Other reports indicate that Minnesota public health officials are still trying to determine that. It is well known that vaccine-type poliovirus can persist in immunocompromised patients for years, and may from time to time provide the virus to infect contacts who may be susceptible. Did this patient acquire the virus from such a contact, or could this be some rare kind of autoinfection?

Curiously, the only other vaccine-derived case of polio in the United States since the use of live virus vaccine was discontinued in 2000 also occurred in Minnesota. Coincidence? Perhaps, but a close relationship between public health and clinical medicine, an excellent clinical laboratory network and a first rate public health laboratory might also be factors. One wonders how many other vaccine-related polio illnesses might have occurred that, for one reason or another, simply escaped detection.

– Theodore C. Eickhoff, MD

Infectious Diseases in Children


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