Freak infection with an eradicated form of polio shows virus’ craftiness - Ars Technica

There are also occasional vaccine-derived polioviruses that circulate in communities with low vaccination rates, which recently occurred in New York.

As such, officials worked to identify which employees had access to type 3 polio in the weeks before the positive sample.

Bilthoven Biologicals placed its infected employee in a house designed for isolation, situated in a community with more than 90 percent vaccination coverage.

Local health workers made sure the person followed strict hygiene measures while they were still shedding viruses.

The infected employee spent the next 33 days in isolation, including over the holidays, until they had three consecutive negative stool samples.

"This event shows that incidents that lead to a breach of containment and even an infection can remain unnoticed and not reported if routine monitoring is not in place," they concluded.