Hidden Polio in Healthy Kids: What It Means for Public Health

On 9 May 2025, a surprising news from Papua New Guinea's health authorities: a type of poliovirus, circulating vaccine-derived poliovirus type 2 (cVDPV2), was detected in stool samples taken from two healthy children in La City, Morobe province. The news comes following the detection in April of environmental samples, which already indicated the virus's presence.

The kids were asymptomatic, yet the virus was circulating in their systems. This asymptomatic spread is now giving rise to concern, especially in a region where polio vaccine coverage is frighteningly low.

Why the Virus Found in Healthy Kids Is a Red Flag

While children are healthy and not ill, the virus they harbor is a public health risk. It means cVDPV2 is quietly circulating within the community, potentially infecting other people who are unvaccinated or under-vaccinated.

Morobe province had as low as 44% third-dose oral polio vaccine (OPV3) coverage in 2024, far from the threshold required for effective herd immunity.

How does polio spread without displaying symptoms?

Here comes the catch: Polio is often symptom-free. In fact, 70% of polio infections are totally asymptomatic. People don't feel a thing but can still shed the virus from their stool and transmit it unknowingly, particularly in unsanitary places.

Some 1 in 4 infected individuals might have mild symptoms like:

• Fever

• Sore throat

• Headache

• Upset stomach

• Fatigue

These flu-like symptoms tend to clear in a matter of days and are rarely ever associated with polio unless they are tested properly.

But in rare but severe situations, the virus invades the nervous system and results in:

• Neck pain (spinal cord and brain meningitis)

• Paresthesia (limb tingling)

• Paralysis

• Delayed-onset complications such as post-polio syndrome, years after the initial infection

What needs to be done now?

The finding of cVDPV2 in asymptomatic children is an eye-opener. Highlights the need for:

• Increased vaccination in high-risk communities

• Improved surveillance to detect silent transmission early

• Increased public awareness of the importance of vaccination

A single unvaccinated child in a low-coverage community can be the breeding ground for an outbreak. Persistence in vaccination, education, and surveillance is the key to preventing polio.

(Input from various sources)

(Rehash/Muhammad Faisal Arshad/MSM)