Concept
A zoster vaccine is a vaccine that reduces the incidence of herpes zoster (shingles), a disease caused by reactivation of the varicella zoster virus, which is also responsible for chickenpox. Shingles provokes a painful rash with blisters, and can be followed by chronic pain (postherpetic neuralgia), as well as other complications. Older people are more often affected, as are people with weakened immune systems (immunosuppression). Both shingles and postherpetic neuralgia can be prevented by vaccination. Two zoster vaccines have been approved for use in people over 50 years old. Shingrix (GSK) is a recombinant subunit vaccine which has been used in many countries since 2017. Zostavax (Merck), in use since 2006, is an attenuated vaccine which consists of a larger-than-normal dose of chickenpox vaccine. Unlike Shingrix, Zostavax is not suitable for people with immunosuppression or diseases that affect the immune system. Zostavax was discontinued in the United States in November 2020. Shingrix appears to prevent more cases of shingles than Zostavax, although side effects seem to be more frequent. Another vaccine, known as varicella vaccine, is used to prevent diseases caused by the same virus. Zoster vaccination is used to prevent shingles and its complications, including postherpetic neuralgia. It can be considered a therapeutic vaccine, given that it is used to treat a latent virus that has remained dormant in cells since chicken pox infection earlier in life. The two available zoster vaccines are intended for use in people over the age of 50. it remained to be confirmed whether a booster dose was required, but the Advisory Committee on Immunization Practices (ACIP) in the United States recommends Shingrix for adults over the age of 50, including those who have already received Zostavax. The ACIP voted that Shingrix is preferred over Zostavax for the prevention of zoster and related complications because data showed vaccine efficacy of more than 90% against shingles across all age groups.