How long does a cold last in babies? The common cold usually lasts seven to 10 days (day three is often the worst), though a residual cough may linger for longer. The incubation period for a cold is between one and four days. It’s typically most contagious a day or two before symptoms appear but can be passed along when the cold is already …

https://www.whattoexpect.com/first-year/health-and-safety/colds-in-babies/