Polio – Symptoms and Causes

Overview

Polio is a virus-based illness that attacks the nervous system. It primarily affects the spinal cord and brain stem. In serious cases, it can cause paralysis, breathing difficulties, and sometimes death. The medical term for this condition is poliomyelitis.

Due to worldwide vaccination campaigns, polio cases have decreased significantly in recent years. However, the virus continues to spread in regions where vaccination rates remain low.

The CDC issues travel alerts for countries with higher polio risks. These areas are typically found in:

• Africa
• Middle East
• Southern and Central Asia

For travelers planning visits to these high-risk regions, proper vaccination is essential. Adults who have been previously vaccinated should receive an IPV booster dose before traveling to areas with active polio transmission. This booster provides lifelong immunity against the disease.

Maintaining high vaccination rates globally remains critical to preventing polio outbreaks and protecting vulnerable populations from this serious disease.

Signs and Symptoms

Mild Polio

About 5% of people with poliovirus develop mild symptoms that last 2-3 days. These flu-like symptoms include:

• Fever
• Headache
• Muscle pain
• Sore throat
• Stomach discomfort
• Reduced hunger
• Feeling sick
• Throwing up

Non-paralytic Polio

Around 1% of infected people experience this more serious form. It lasts longer than mild polio but doesn’t cause paralysis. Symptoms include:

• Stronger flu-like symptoms
• Neck pain or stiffness
• Pain or stiffness in arms or legs
• Strong headaches

Some people may seem to improve briefly before entering a second phase with:

• Stiff spine and neck
• Reduced reflexes
• Muscle weakness

Movement-limiting Polio

This rare but dangerous form begins like non-paralytic polio but gets worse. Symptoms include:

• Severe pain
• Unusual sensitivity to touch
• Tingling feelings
• Muscle spasms or twitches
• Muscle weakness leading to paralysis

Paralysis most often affects one leg, followed by one arm. Other possible symptoms include:

• Breathing muscle paralysis
• Problems swallowing

After-Polio Condition

This involves new problems appearing decades after the original illness. Common signs include:

• Worsening muscle or joint weakness and pain
• Tiredness
• Muscle shrinking
• Trouble breathing or swallowing
• Sleep breathing problems like sleep apnea
• Less tolerance for cold temperatures

When to Get Medical Help

Polio symptoms look like other nervous system viral diseases. Getting the right diagnosis quickly is important.

If you had polio in the past, talk to your doctor if you notice new or worsening symptoms.

What Causes Polio

Polio comes from the poliovirus, which attacks nerve cells in the spinal cord and brain stem that control how muscles move.

The virus comes in two main forms: wild-type poliovirus (which is now rare in most countries) and vaccine-derived poliovirus (VDPV), which causes most polio cases today.

VDPV develops in areas where not enough people get vaccinated. It starts from the weakened virus in oral polio vaccines. While this weakened virus doesn’t usually cause illness in vaccinated people, it can spread in communities.

In areas with low vaccination rates, the virus can circulate for extended periods and eventually change into a form that causes disease similar to wild poliovirus.

The United States has reported some VDPV cases, mostly in unvaccinated people or those with weakened immune systems. A 2022 case in New York occurred in an area with below-average vaccination rates.

Since 2000, the US has used an injected, inactive polio vaccine that doesn’t create VDPV risk.

People can spread poliovirus even if they don’t feel sick. The virus passes through:

• Fecal matter (stool)
• Droplets from coughs or sneezes
• Contaminated water

The virus enters a new person’s body through the mouth. This makes it highly contagious in several common situations:

• When people don’t wash their hands after using the toilet
• Before eating with unwashed hands
• After coughing without covering the mouth
• Through drinking water contaminated with feces

Good hygiene practices like handwashing and proper sanitation help reduce the spread of poliovirus in communities.

Risk Factors

Polio is more common in children. However, all unvaccinated people face the risk of getting infected with this disease. If you haven’t received the polio vaccine, you should talk to your doctor about getting vaccinated.

Possible Health Problems

Serious breathing difficulties from this illness can lead to death. People who recover might face lasting health issues:

• Permanent loss of muscle control
• Shortened muscles causing bone or joint deformities
• Long-lasting pain
• Post-polio syndrome, which affects survivors years later

These complications can significantly impact quality of life and may require ongoing medical care.

Stopping Polio

Polio Shots

Getting vaccinated is the best way to prevent polio. Children should receive four doses of the inactivated poliovirus vaccine (IPV) according to this schedule:

• At 2 months old
• At 4 months old
• Between 6 and 18 months old
• Between 4 and 6 years old (when starting school)

If your child has missed any doses, speak with your healthcare provider about creating a catch-up vaccination plan.

Vaccination for Grown-ups

Most adults in the United States have protection against polio from childhood vaccines. The risk of exposure to polio in the U.S. is very low.

However, adults planning to travel to or live in areas with high polio rates should get additional protection.

For adults with complete childhood vaccination:

• Get a one-time IPV booster dose

For adults with incomplete or unknown vaccination:

• Get three IPV doses on this schedule:
  1. First dose
  2. Second dose (1-2 months after first)
  3. Third dose (6-12 months after second)

Talk to your doctor if you’re unsure about your vaccination history.

Vaccine Protection

The IPV vaccine is safe for most people. It may provide less protection in severely immunocompromised individuals. The most common side effects are pain and redness where the shot was given.

Some people may have allergic reactions to IPV. The vaccine contains small amounts of antibiotics (streptomycin, polymyxin B, and neomycin). These might cause reactions in people allergic to these medications.

Someone who has a severe reaction to the first IPV dose won’t receive additional doses.

Signs of an allergic reaction include:

• Skin issues (hives, itching, flushed or pale skin)
• Low blood pressure
• Breathing problems (wheezing, throat swelling)
• Fast, weak pulse
• Stomach problems (nausea, vomiting, diarrhea)
• Feeling dizzy or fainting

If you or your child shows these signs after getting vaccinated, seek medical help right away.