People are definitely contagious while they have symptoms, which can last 2–4 weeks or even longer. Health experts aren't sure how long people with mono stay contagious after symptoms are gone, but it seems they can spread the infection for months after that. Then, the virus stays dormant (inactive) in the body for the rest of a person's life. Mar 06, · You can pass the virus to other people through your saliva for up to three months after your symptoms subside. Some studies have reported that you may still be contagious for up to 18 months. Estimated Reading Time: 3 mins. If someone who has mono uses an object like a fork or spoon, the virus is probably still contagious as long as the object is still moist. EBV can be spread through blood and shambhalafundacion.orgted Reading Time: 4 mins.