Delaware County is a county in southeastern Pennsylvania, adjacent to Philadelphia. In late June 2026, a wastewater signal there was reported as a possible measles detection tied to World Cup travel through Chester County, but the Philadelphia Department of Public Health retested it, found it negative, and retracted the finding as a false positive on 6 July. No clinical cases were ever linked to the signal. Delaware County is a distinct place from the US state of Delaware, which separately declared its own measles outbreak in July 2026.

Common Questions

Reference

Where is Delaware County, Pennsylvania?

Delaware County is in southeastern Pennsylvania, adjacent to Philadelphia.

What is the difference between Delaware County and the state of Delaware?

Delaware County is a county in southeastern Pennsylvania, adjacent to Philadelphia; the state of Delaware is a separate US state that declared its own measles outbreak in July 2026.

What happened with the Delaware County measles signal?

A wastewater measles signal in Delaware County, Pennsylvania was retested and found negative; the Philadelphia Department of Public Health retracted it as a false positive on 6 July 2026.Source: Philadelphia Department of Public Health

How the World Sees Them

World Health Organization

The outbreak is serious but is not the next COVID.

IGWG co-chair Tovar da Silva Nunes

Member States have once again demonstrated their commitment to completing the PABS annex.

European Centre for Disease Prevention and Control

the possible involvement of local Anopheles mosquitoes cannot be excluded

Uganda's Ministry of Health

Unless they have other reasons, they should definitely lift the restrictions off the country.

Africa CDC

Transparency builds trust, accelerates delivery and saves lives.

Médecins Sans Frontières

a megafire, with multiple simultaneous focal points

DR Congo Ministry of Health

is evolving favourably

Written with AI from Lowdown's published reporting. Not individually reviewed by an editor. Updated 31 July 2026. Editorial standards.