Assessment of Enterovirus Excretion and Identification of VDPVs in Patients with Primary Immunodeficiency in India: Outcome of ICMR–WHO Collaborative Study Phase-I

The emergence of vaccine-derived polioviruses (VDPVs) in patients with Primary Immunodeficiency (PID) is a threat to the polio-eradication program. In a first of its kind pilot study for successful screening and identification of VDPV excretion among patients with PID in India, enteroviruses were assessed in stool specimens of 154 PID patients across India in a period of two years. A total of 21.42% of patients were tested positive for enteroviruses, 2.59% tested positive for polioviruses (PV), whereas 18.83% of patients were positive for non-polio enteroviruses (NPEV). A male child of 3 years and 6 months of age diagnosed with Hyper IgM syndrome was detected positive for type1 VDPV (iVDPV1) with 1.6% nucleotide divergence from the parent Sabin strain. E21 (19.4%), E14 (9%), E11 (9%), E16 (7.5%), and CVA2 (7.5%) were the five most frequently observed NPEV types in PID patients. Patients with combined immunodeficiency were at a higher risk for enterovirus infection as compared to antibody deficiency. The high susceptibility of PID patients to enterovirus infection emphasizes the need for enhanced surveillance of these patients until the use of OPV is stopped. The expansion of PID surveillance and integration with a national program will facilitate early detection and follow-up of iVDPV excretion to mitigate the risk for iVDPV spread.