Cutar da ke yaduwa shine yanayi da cuta ke kama wanda aka riga akai wa allurar rigakafi daga irin cutar da ake nufin rigakafin. A sauƙaƙe, suna faruwa lokacin da alluran rigakafi suka kasa samar da rigakafin ƙwayoyin cuta waɗanda aka tsara su don yin niyya. An gano cewa breakthrough infection sun faru akan mutane daban daban da aka riga akai wa allurar rigakafin cututtuka daban -daban da suka haɗa da Mumps, Varicella (Chicken Pox), da Influenza. Halayen wadannan cututtuka sun dogara ne akan kwayoyin cututtukan da kanta. Sau da yawa, kamuwa da cuta a cikin mutumin da aka yi wa allurar yana haifar da ƙananan alamun cutar kuma yana da ɗan gajeren lokaci fiye da yadda aka kamu da cutar ta halitta. Abubuwan da ke haifar da kamuwa da cuta sun haɗa da rashin kulawa ko adana alluran rigakafi, maye gurbi a cikin ƙwayoyin cuta da toshe ƙwayoyin rigakafi . Saboda waɗannan dalilai, alluran rigakafi ba safai suke tasiri 100% ba. An kiyasta allurar rigakafin mura na yau da kullun yana ba da rigakafin mura a cikin 58% na masu karɓa.