Asymptomatic immunodeficiency-associated vaccine-derived poliovirus infections in two UK children

Immunodeficiency-Related Vaccine-Derived Poliovirus (iVDPV) Excretion in an Infant with Severe Combined Immune Deficiency with Spillover to a Parent

In order to maintain the polio eradication status, it has become evident that the surveillance of cases with acute flaccid paralysis and of environmental samples must be urgently supplemented with the surveillance of poliovirus excretions among individuals with inborn errors of immunity (IEI). All children with IEI were screened for the excretion of poliovirus during a collaborative study conducted by the ICMR-National Institute of Virology, Mumbai Unit, ICMR-National Institute of Immunohaematology, and World Health Organization, India. A seven-month -old male baby who presented with persistent pneumonia and lymphopenia was found to have severe combined immune deficiency (SCID) due to a missense variant in the RAG1 gene. He had received OPV at birth and at 20 weeks. Four stool samples collected at 4 weekly intervals yielded iVDPV type 1. The child's father, an asymptomatic 32-year-old male, was also found to be excreting iVDPV. A haploidentical hematopoietic stem cell transplant was performed, but the child succumbed due to severe myocarditis and pneumonia three weeks later. We report a rare case of transmission of iVDPV from an individual with IEI to a healthy household contact, demonstrating the threat of the spread of iVDPV from persons with IEI and the necessity to develop effective antivirals.

Stem Cell Transplant in Immune-deficiency-associated Vaccine-derived Poliovirus

Patients with severe primary immunodeficiency are at risk for complications from live-attenuated vaccines. Here, we report a case of a vaccine-associated paralytic polio and Bacille Calmette-Guérin disease in a 6-month-old girl with severe combined immunodeficiency resulting from homozygous recombinant activating gene 1 deficiency. The patient was successfully treated with intravenous immunoglobulins and oral pocapavir for poliovirus, and antimycobacterial therapy for regional Bacille Calmette-Guérin disease, allowing stem cell transplant. Following transplantation, poliovirus type 3 with 13 mutations was detected from cerebrospinal fluid but not from stool, indicating ongoing viral evolution in the central nervous system despite pocapavir treatment. Clinical improvement and immune reconstitution allowed the patient to be successfully discharged with no further detection of poliovirus.