How long does varicella immunizations last?

Depends on take: The vaccine for chickenpox was developed in the late 70's in japan and adopted for use in the us after lengthy review by the fda in the 90's. The present schedule of 2 doses in is thought to effect a perminent although possibly partial benefit in >90%. Mild cases are occasionally seen in vaccinated kids, but deaths have dropped from ~50/yr to zero since general use became the rule.