Amtrak has issued a warning to passengers about potential measles exposure after health officials confirmed an infected individual travelled on a crowded train from Philadelphia to Baltimore-Washington International (BWI) Airport.
Timeline and Locations of Potential Exposure
The journey took place between January 7 and January 8. Maryland health authorities have listed several specific locations as possible exposure sites linked to the unidentified traveller.
The locations include Philadelphia International Airport, Terminal A East from 7:50 pm to 11:00 pm on January 7. The individual then boarded an Amtrak train from Philadelphia's 30th Street Station to Washington, DC, travelling between 9:00 pm and 11:30 pm on January 7.
Subsequently, they took the Amtrak shuttle to BWI Airport from 10:45 pm on January 7 to 1:30 am on January 8, followed by the BWI long-term parking shuttle from 11:00 pm on January 8 to 2:00 am.
Officials have not disclosed whether the infected person showed symptoms like fever or rash during travel, their contagious phase status, or their vaccination history.
Urgent Public Health Advice and Measles Resurgence
Health officials advise anyone unvaccinated who was at these locations to contact a healthcare provider or local health department. They should monitor for early symptoms for 21 days following exposure.
Key symptoms to watch for include a fever above 101 degrees Fahrenheit, cough, runny nose, and red, watery eyes. The characteristic facial rash typically appears 10 to 14 days after exposure and spreads over several days. An infected person can transmit the virus from four days before the rash appears until four days after.
This incident occurs amid a significant measles resurgence in the United States. Last year saw 2,144 confirmed cases, the highest annual total since the disease was declared eliminated in 2000.
Current hotspots include Utah, with 176 total cases for the 2025-2026 period, and South Carolina, which has reported a statewide total of 310 infections. Nationally, 11% of cases have required hospitalisation, with nearly 20% of infected children under five being admitted.
The Critical Role of Vaccination
Meg Sullivan, Maryland Department of Health’s deputy secretary for Public Health Services, emphasised: “Vaccination remains essential to protecting ourselves, our families, and our communities against measles and other infectious diseases.”
According to the CDC, 93% of measles cases occur in unvaccinated individuals or those with unknown vaccine status. The odds of infection for a fully vaccinated person are very low, at about 3%, and symptoms are typically far milder.
The population-wide immunity threshold needed to prevent outbreaks is approximately 95%. However, current levels have fallen to below 93%, increasing vulnerability.
Measles is the world's most contagious disease. An unvaccinated person has a 90% chance of infection if they briefly share air with a contagious person. The disease kills about three in every 1,000 infected people and can cause severe complications like pneumonia and brain swelling.
Before the MMR vaccine's introduction in the 1960s, measles caused millions of deaths globally annually. The World Health Organization estimates vaccinations prevented 60 million deaths between 2000 and 2023.
