Molluscum contagiosum is a minor viral infection that causes skin bumps. There are many uncertainties about its epidemiology and transmission. The infection is only a nuisance, never a serious health risk, and therefore little research has been done.
In adults, MC most commonly affects the genital or nearby areas, such as the pubic area, and generally is considered to be sexually acquired. However, this is a little controversial, and some cases may be acquired by other routes. MC is most common in young children, in whom the virus is transmitted by toys or other objects that can go from mouth to mouth, especially in places like daycare settings. Some infections in adults may result from contact with infected children. (However, it is not clear why such infections should be most common in the genital area, which is one reason that most experts believe sexual transmission is the usual explanation.) The incubation period -- that is, the time from exposure to symptoms -- hasn't been studied in adults, but probably is usually 1-2 months.
It is believed that such childhood infections result in immunity that protects from future new infections. Therefore, many or most adults are immune and do not get infected even if exposed. Finally, when adults are infected, many may be asymptomatic. Some may truly have no visible lesions, with truly asymptomatic infections; others might have lesions they didn't notice, either because they were small or because they occurred difficult to see locations, like inside the vagina, around the anus, etc.
So on one hand, the appearance of MC in one member of a sexual foursome suggests that one of the others is infected and was the source of his or her infection. But not necessarily; perhaps the initial infection was not sexually acquired at all. Other members of the foursome might not become infected from the original case, because of past childhood infection and current immunity.
It would be reasonable for the other 3 members of your sexual group to be examined, either by their primary care providers (for the women, that probably means a gynecologist) or a dermatologist. In any case, this is not a cause for serious worry. The biggest concern isn't MC itself, but whether its appearance indicates risk for other STDs. Therefore, it would be a good idea for all members of the group to have standard tests for chlamydia, gonorrhea, syphilis, and perhaps HIV, just to be maximally safe.
I hope this helps. Best wishes--- HHH, MD
I'm glad it was helpful. Once MC clears, it's gone forever and there is nothing to transmit; when the bumps are gone, you can assume the virus is gone. After that the person probably is immune from catching it again.
Thank you for your information. It was very helpful. I just still have a couple of questions. Once you have this, it has cleared up and you are immune can you still spread it to others? Is it something you always have or does it go away when cleared up?