Influenza, commonly known as the flu, is a highly contagious viral infection that primarily affects the upper respiratory ...

Each year, seasonal flu sickens about 1 billion people worldwide and causes approximately 290,000 to 650,000 respiratory ...

To stop the spread of an infectious disease like measles, you don’t have to vaccinate everyone. But you do have to vaccinate many. Just how many? To let you discover for yourself, we simulated an ...

COVID-19 also may cause long-lasting symptoms, unlike the flu or cold, that seem unrelated to the original infection. The two illnesses are both contagious and have similar symptoms, but are ...