I en undersøgelse til sammenligning af 1 dosis (N=1114) med 2 doser (N=1102) levende skoldkoppevaccine (Oka/ Merck) vurderedes vaccinens effekt mod skoldkopper i alle sværhedsgrader over en tiårig observationsperiode til at være 94% for 1 dosis og 98% for 2 doser (p < 0, 001).
In a study comparing 1 dose (N=1114) to 2 doses (N=1102) of Varicella Vaccine live (Oka/ Merck), the estimated vaccine efficacy against all severities of varicella disease for the 10-year observation period was 94% for 1 dose and 98% for 2 doses (p < 0.001).