Mumps resurges in the US as Maryland battles a growing outbreak

Mumps cases are rising again in the US, with Maryland reporting a significant outbreak. As of February 19, 2023, the state has confirmed 26 infections, including 19 confirmed and 7 probable cases. Nationwide, the Centers for Disease Control and Prevention (CDC) has recorded 34 cases across 11 jurisdictions by late February.

Mumps was once a common childhood illness in the US, with over 152,000 cases reported in 1968 alone. Widespread vaccination later slashed numbers dramatically, dropping cases to just 231 by 2003. However, since 2006, outbreaks have gradually increased, particularly in close-contact settings like schools, sports teams, and university dormitories.

The virus spreads through respiratory droplets and saliva, often before symptoms appear. Those infected may develop swelling of the salivary glands, fever, headache, muscle pain, fatigue, and loss of appetite—usually within 2–3 weeks of exposure. While most recover with rest and symptom relief, complications can arise, including inflammation of the testicles, ovaries, or brain, as well as permanent hearing loss.

The MMR vaccine remains the best protection, with two doses estimated to be 86% effective. Yet outbreaks can still occur, even among vaccinated groups, due to waning immunity and prolonged close contact. Health officials urge adults born after 1957 to check their vaccination status. During outbreaks, certain high-risk individuals may need an extra dose.

Maryland's outbreak highlights the ongoing risk of mumps, despite high vaccination rates. Infected individuals are advised to isolate for five days after symptoms begin to prevent further spread. Public health efforts continue to focus on vaccination and monitoring in high-risk environments.