- Contraception: Nonsterilised males must agree to refrain from fathering a child from the point of entering quarantine until the Day 28 follow up visit. Use of one effective form of contraception is acceptable. Sexually active females of childbearing potential must agree to use 2 effective methods of avoiding pregnancy that are deemed to be effective from the point of entry into the quarantine unit until the Day 28 follow up visit. Acceptable forms of effective contraception include: