You're at greatest risk of polio if you haven't been immunized against the disease. In areas with poor sanitation and sporadic or nonexistent immunization programs, the most vulnerable members of the population pregnant women, the very old and very young are especially susceptible to poliovirus. Polio, which once affected infants and children almost exclusively, now affects people of all ages.
These factors also increase your risk :
- Travel to an area where polio is common or that has recently experienced an outbreak
- Living with or caring for someone who may be shedding poliovirus
- Contact with someone recently vaccinated by oral polio vaccine (if you're unvaccinated)
- Handling laboratory specimens that contain live poliovirus
- A compromised immune system, such as occurs with HIV infection
- Trauma to your mouth, nose or throat such as dental surgery or a tonsillectomy
- Extreme stress or strenuous physical activity after being exposed to poliovirus, both of which can depress your immune system
Paralytic Polio
It's not known why some people infected with poliovirus develop paralysis and others don't. But many of the same factors that put you at risk of polio also make it more likely that you'll develop the paralytic form if you're infected. These risk factors include:
- A compromised immune system
- Pregnancy
- Mouth or throat surgery
- Injury or strenuous physical exercise after exposure to the virus
Post-Polio Syndrome
Although post-polio syndrome still isn't well understood, certain factors may increase your chances of developing this complex of symptoms decades after your initial infection :
- Severe polio infection. The more severe the initial infection, the more likely that you'll have signs and symptoms of post-polio syndrome.
- Age at onset of initial illness. If you acquired polio as an adolescent or adult, rather than as a young child, your chances of developing post-polio syndrome increase.
- Recovery. Paradoxically, the greater your recovery after acute polio, the more likely it is that you'll develop post-polio syndrome. This may be because greater recovery places additional stress on motor neurons.
- Physical activity. If you’ve had polio, engaging in physical activity to the point of exhaustion or fatigue may overwork already-stressed motor neurons.
Recent research results suggest that risk of post-polio syndrome is not as great as had once been thought. A Mayo Clinic study in 2006 that followed polio survivors during a 15-year period found that the physical decline of most polio survivors generally reflected that of the general population and was likely due to aging alone, rather than to post-polio syndrome.
The above information thankfully comes from the Mayo Clinic.com at the following link.