One of the world’s most contagious diseases is making a troubling comeback in the United States, with confirmed cases reported across multiple states and even at two major US airports.

Thanks to advances in modern medicine, widespread vaccination programs, and improved hygiene, many infectious diseases that once devastated populations have been largely controlled or eliminated in developed countries. As medical science has progressed, public health systems have become far better equipped to prevent outbreaks that were once considered inevitable.

However, measles — a disease previously declared eliminated in the US — is now resurging at levels not seen in decades, raising serious concerns among health officials. According to the US Centers for Disease Control and Prevention (CDC), the country has recorded measles case numbers unseen for more than 30 years (CDC).

As of December 30, 2025, the CDC confirmed a total of 2,065 measles cases nationwide, marking the highest annual total since 1992, when 2,126 infections were reported (CDC). Public health experts note that measles cases in the US have been steadily increasing in recent years, largely due to declining vaccination rates in certain communities (Reuters).

Adding to the concern, several cases have been linked to air travel, increasing the risk of wider exposure. The New Jersey Department of Health confirmed that an infected passenger passed through Terminals B and C at Newark Liberty International Airport on December 12. Officials warned that individuals present in those terminals between 7 a.m. and 7 p.m. may have been exposed to the virus (New Jersey Department of Health).

Similarly, the Massachusetts Department of Public Health reported that a traveler who arrived at Boston Logan International Airport on December 11 aboard American Airlines Flight 2384 from Dallas–Fort Worth later tested positive for measles. The individual also stayed at a hotel in Westborough before departing Massachusetts the following day on a JetBlue flight to Las Vegas (Massachusetts Department of Public Health). Authorities are working closely with the CDC and local partners to identify and notify anyone who may have been exposed (CDC).

Measles is a highly contagious viral infection that spreads through airborne respiratory droplets. Early symptoms often resemble a common cold, including fever, cough, and a runny nose, before progressing to a distinctive red, blotchy rash. According to the World Health Organization, measles can remain infectious in the air for up to two hours after an infected person leaves an area, making it particularly dangerous in crowded spaces such as airports (WHO).

While many people recover, measles can lead to serious complications, especially in children under five years old. Common complications include ear infections and severe diarrhea, while more serious outcomes such as pneumonia, brain inflammation (encephalitis), and even death can occur in severe cases (WHO, CDC).

Health experts stress that vaccination remains the most effective defense against measles. The CDC and WHO have both warned that declining immunization coverage has created conditions for outbreaks to re-emerge, even in countries where the disease was once considered eliminated (Reuters, WHO).

As measles cases continue to rise, US health authorities are urging the public to ensure vaccinations are up to date and to remain vigilant, particularly when traveling during busy holiday seasons when exposure risks are higher (CDC).