What is the difference between varicella vaccine and shingles vaccine?
The difference between these vaccines may be confusing, so they are conventionally referred to as chickenpox vaccine and shingles vaccine, to better distinguish them.
Varicella vaccine (also called chickenpox vaccine) is a live varicella virus strain that is formulated for nonimmune individuals. It does not cause widespread infection like wild-type varicella virus but only local infection, enough to stimulate new, protective levels of antibodies. It is typically given in children or adolescents, but adults may receive it. The current FDA-approved varicella vaccine is called Varivax. It may also be formulated with measles, mumps, and rubella (MMR) vaccine as MMRV, or ProQuad.
Childhood vaccination with Varivax or ProQuad is given at age 12-15 months of age and 4 to 6 years of age. Varicella vaccine sometimes causes local blisters within two weeks in the injection area. Because the dose of virus is higher in Varivax, there is a small risk of transmission to others, and contact with immune suppressed people and nonimmune pregnant women should be avoided until healed. As live vaccines, ProQuad and Varivax should not be given to those with immune system problems.
Varicella vaccination is important for children, but it should also be considered for nonimmune adults who work with children, women who are planning pregnancy, health care professionals, travelers, correctional institutions, and military personnel. Adults born before 1980, when chickenpox was common, are assumed to have antibodies to it. Adults born after 1980 or outside the U.S. can be screened for VZV antibodies before being offered vaccine. It is given as two doses at least four to eight weeks apart at ages 13 and over. Adults 50 years of age and over will usually receive the shingles vaccine instead.
Varicella-zoster vaccine (shingles vaccine) is formulated to boost varicella antibodies in older adults. The shingles vaccines are indicated for adults over 50 years of age; most adults currently in this age group have had chickenpox, whether they recall it or not. There are two brands of FDA-approved shingles vaccines: Zostavax and Shingrix. Zostavax is a live varicella virus vaccine that is FDA-approved to be given in one dose after age 50, however, there was no data on duration of protection, and the risk of complications from shingles is highest in those over 60 years of age. For this reason, the ACIP recommended administering Zostavax to those aged 60 and above; this decision was supported by later data showing a significant drop in protection 10 years after vaccination. Zostavax is a live vaccine, and some may develop blisters at the site of injection or very rarely disseminated lesions. Due to the theoretical risk of transmission, lesions should be covered, and contact with immunosuppressed or nonimmune pregnant individuals should be avoided until healed.
While boosters of Zostavax were being debated, the newer Shingrix vaccine was developed, and is now preferred. Shingrix is a non-live antigen (a VZV protein that stimulates antibodies) with an adjuvant (a molecule that activates the immune system). It is given as two doses at least eight weeks apart. Data has shown that protective levels of antibodies from Shingrix last much longer than that produced by Zostavax. As of January 2018, the ACIP has recommended Shingrix as the preferred vaccine for the prevention of shingles and its complications in older adults, starting at the FDA-approved age of 50.
An anticipated advantage of a non-live vaccine, Shingrix may have potential use in immunocompromised individuals who are at risk for more serious complications of shingles, such as dissemination. The ACIP awaits further evidence before recommending it as safe and effective in these individuals.