A unique combination of killed antigens and an effective adjuvant system makes Fel-O-Vax Lv-K IV easy on pets because all this protection is delivered in one shot. Fel-O-Vax IV offers the same protection without the Leukemia. Fel-O-Vax PCT does not have Chlamydia or leukemia included. Fel-O-Vax IV and Fel-O-Vax are popular vaccines used for the first and second vaccinations of the kitten vaccine series. Fel-O-Vax Lv-K IV is then often given for the last two vaccinations in the series.