From the Guidelines
Paralytic polio occurs in a very small percentage of poliovirus infections, with the exact frequency not specified in the provided study. The progression to paralytic polio is a complex process that involves the replication of the virus in the oropharynx and intestinal tract, followed by viremia and infection of the central nervous system 1. The clinical manifestations of paralytic polio can be severe, with spinal paralysis typically being asymmetric and more severe proximally than distally, and bulbar paralysis potentially compromising respiration and swallowing 1. Some key points to consider about paralytic polio include:
- The progression to maximum paralysis is rapid, usually within 2-4 days, and is often associated with fever and muscle pain 1
- Paralytic polio can be fatal in 2%--10% of cases 1
- Many patients recover at least some muscle function after the acute episode, and the prognosis for recovery can usually be established within 6 months after onset of paralytic manifestations 1 It is essential to note that vaccination remains the most effective prevention method against all forms of polio, and efforts to prevent the spread of the virus are crucial in reducing the risk of paralytic polio.
From the Research
Polio and Paralysis
- Polio is a contagious disease caused by the poliovirus, which can lead to paralysis and even death 2.
- The virus infects children under 5 years and most infections are asymptomatic and self-limiting, but it can spread to the central nervous system and cause paralysis 2.
- Poliovirus can cause poliomyelitis and lifelong paralysis, with wild poliovirus types 2 and 3 eradicated, but wild poliovirus type 1 and vaccine-derived polioviruses still circulating in multiple countries worldwide 3.
Types of Polio Infections
- Polio infections can be categorized into:
- Inapparent infection without symptoms
- Mild illness (abortive poliomyelitis)
- Aseptic meningitis (nonparalytic poliomyelitis)
- Paralytic poliomyelitis 4
- The risk of vaccine-associated paralytic poliomyelitis (VAPP) varies by country income level, with a global annual burden estimate of 498 cases (range, 255-1018) 5.
Vaccine-Associated Paralytic Poliomyelitis
- VAPP is a rare adverse event associated with oral poliovirus vaccine (OPV) 5.
- The introduction of inactivated poliovirus vaccine (IPV) can reduce the risk of VAPP, with a planned universal introduction likely to substantially decrease the global VAPP burden by 80%-90% 5.
- Successful introduction of IPV into the public sector Expanded Program on Immunization (EPI) program has been attributed to comprehensive planning, preparation, implementation, robust surveillance for adverse events after immunization (AEFI), and monitoring of vaccination coverage 6.