Pill packages have active pills (with hormones) and placebo pills (no hormones). The number of placebo pills can vary depending on the type of pill used. Your menstrual period should occur during the placebo pills due to lack of hormones. You are still protected from pregnancy during the placebo pills.
Making the Case against the biting midge: evidence is building that the biting midge, Culicoides sonorensis, is a vector of vesicular stomatitis virus (VSV), which causes significant economic losses in cattle, horses, and swine.
VSV [Internet]; Jul 28, 2016 [cited 2016 Jul 28]. Available from: http://www.allacronyms.com/VSV. 'VSV', All Acronyms, 28 July 2016, <http://www.allacronyms.com/VSV> [accessed 28 July 2016] All Acronyms, VSV (Jul. 28, 2016, 11:07 AM), available at http://www.allacronyms.com/VSV.