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

## TL;DR

A 6-month-old girl with a rare immune deficiency developed vaccine-related diseases and was successfully treated with immunoglobulins, antiviral drugs, and a stem cell transplant.

## Contribution

This case highlights successful treatment and stem cell transplant in a patient with immune deficiency and vaccine-derived poliovirus.

## Key findings

- The patient was successfully treated with intravenous immunoglobulins and oral pocapavir for poliovirus.
- Stem cell transplant led to clinical improvement and immune reconstitution.
- Poliovirus type 3 with 13 mutations was detected in cerebrospinal fluid but not in stool post-transplant.

## Abstract

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.