Can Non-Polio Enteroviruses Be Tamed with a Vaccine to Minimize Paralysis Caused by Them?

Abstract

Background: While we are inching towards global eradication of polio, the paralysis due to non-polio viruses (NPEV) poses greater challenge. Factors responsible for causing Acute Flaccid Paralysis (AFP) were studied in 3596 AFP patients in 64 districts of Uttar-Pradesh, India, to observe indirect relationship of AFP with wild polio as well as NPEV. A recent study suggests the need to investigate polio virus negative but NPEV positive AFP cases. Methods: The lab results of the stool samples of these children were line listed and analysed to observe the association of various factors with respect to presence of paralysis on 60 follow-up days. Taking zero OPV dose AFP cases as a biological base, we studied the relationship of presence of paralysis at 60 follow-up days to that of presence of NPEV in stool samples while polio virus was present or absent. Results: 70 of the 86 AFP cases (81%) with zero OPV dose and having only NPEV isolated in stool samples were having paralysis at 60 follow-up days. There were 4.54% (162) AFP cases, which did not carry any polio virus but were having NPEV isolated in the stool samples and paralysis at 60 follow-up days. 79% (75/95) of zero OPV dose children, who were having residual weakness at 60 follow-up days, were carrying both polio virus as well as NPEV in their stool samples. Total AFP cases, having residual weakness at 60 follow-up days and having NPEV in stool samples, decreased with increase in OPV doses; a behavior similar to what wild polio viruses (WPV) have to OPV. Conclusions: Maybe polio like NPEV is active for causing severe paralysis in children and is responding to the OPV. As is evident in the studies by M. Margalith, B. Fattal et al. [1] that there is an antibody response to the enteroviruses, we can think of coming out with a vaccine against the enteroviruses. Therefore, enterovirus vaccine can be produced on similar lines to that of OPV, as now we have enough isolates of NPEV. Effective NPEV surveillance system also needs to be in place.