PROPER use of a condom is the key here. If you put the condom on when the clothes come off instead of waiting to put it on just for penetration, the reduction in transmission of hpv is 90%. Since mollscum and hpv are transmitted in similar fashions, you can assume it would greatly reduce transmission of mollsucum too if you used properly. condoms reduce transmission of genital herpes by 30%.
direct skin on skin contact can be pretty extensive when it comes to outercourse/foreplay. if you aren't aware of your partner's std status or history, it's best to keep underwear on until it's time for actual sex for more protection if you are concerned about std's.
also remember that barrier protection is important for oral sex too if you aren't aware of your partner's std status or history.
grace
Condom almost protects you from STD.Better consult your physician for more information.
It is the ones that are transmitted from skin to skin contact. The condom does not cover the entire genital area. Therefore, herpes and hpv, and molluscom are still transmittable. Also, if there is a syphilis sore in a location that can come in contact with your skin, it can be transmitted. But syphilis is rare in the US, so that is not of huge concern. The other std's require fluid transfer.