Question: how long are you contagious with parainfluenza virus?
Answer: With HPIV-3, the exact period of time you're contagious hasn't been determined. However, it has been shown that viral shedding, and therefore the risk of passing on HPIV-3, typically occurs within the first 3 to 10 days of symptoms. In rare cases, viral shedding has been seen up to three to four weeks.