I kliniske forsøg med raske forsøgspersoner, som fik 1 dosis levende skoldkoppevaccine (Oka/ Merck), kunne skoldkoppeantistoffer påvises hos de fleste i op til 10 år efter vaccinationen.
In clinical studies involving healthy subjects who received 1 dose of Varicella Vaccine live (Oka/ Merck), detectable varicella antibodies were present in most individuals tested for up to 10 years postvaccination.