They would not automatically be contagious right away. The incubation period is 1-4 days for influenza. Depending on when a person develops symptoms, you are able to establish the exposure period (when the person is considered contagious). So say you are exposed on day zero, develop symptoms on day three, the exposure period would start on day two. Anyone the person encountered on day two and on may have been exposed. In a hospital setting, we would isolate a patient for seven days after symptom onset, or 24 hours after resolution of fever and symptoms -whichever is longest.
Source: CDC
Calise10 t1_ixsurgj wrote
Reply to How soon after exposure is the flu contagious? by AcJc_0604
They would not automatically be contagious right away. The incubation period is 1-4 days for influenza. Depending on when a person develops symptoms, you are able to establish the exposure period (when the person is considered contagious). So say you are exposed on day zero, develop symptoms on day three, the exposure period would start on day two. Anyone the person encountered on day two and on may have been exposed. In a hospital setting, we would isolate a patient for seven days after symptom onset, or 24 hours after resolution of fever and symptoms -whichever is longest. Source: CDC