The timing of symptom onset depends on lots of factors, including the amount of virus to which someone was exposed, Hotez says. Their level of pre-existing immunity may also affect the likelihood or ...

(NEXSTAR) – It’s that time of year again. The coughing, sneezing and sniffling is all around us, as both influenza and COVID-19 start to spread. When you start to feel sick, it can be hard to tell ...