Zoster vaccine

Zoster Vaccine is a vaccine used for the prevention of shingles, a disease caused by the varicella zoster virus (VZV), which is also responsible for chickenpox in children. The vaccine decreases the risk of developing shingles and the long-term pain from post-herpetic neuralgia (PHN) among older adults. There are two types of zoster vaccines: the live Zostavax and the recombinant, adjuvanted Shingrix.

Indications

Zoster vaccines are primarily indicated for the prevention of shingles in individuals 50 years of age and older. They are also recommended for individuals 60 years of age and older, regardless of whether they report a prior episode of shingles, to reduce the risk of VZV reactivation. The Centers for Disease Control and Prevention (CDC) recommends the recombinant zoster vaccine as the preferred vaccine for the prevention of herpes zoster and related complications.

Mechanism of Action

The live zoster vaccine, Zostavax, works by boosting the immune system's response to the VZV, helping to prevent it from reactivating as shingles. The recombinant zoster vaccine, Shingrix, contains a VZV glycoprotein E antigen and an adjuvant system to enhance the body's immune response to the antigen, providing strong and sustained protection.

Efficacy

Clinical trials have demonstrated that the recombinant zoster vaccine is over 90% effective at preventing shingles and PHN in individuals 50 years and older. Its efficacy is maintained across various age groups, including those over 70 years of age. The live zoster vaccine has shown a lower efficacy, which decreases with increasing age, making the recombinant vaccine the preferred option.

Administration

The recombinant zoster vaccine is administered as a two-dose series, with the second dose given two to six months after the first. The live zoster vaccine is given as a single dose. Vaccination should be deferred in individuals experiencing an acute episode of shingles or those with a weakened immune system due to disease or medication.

Side Effects

Common side effects of the zoster vaccines include pain and swelling at the injection site, headache, muscle pain, and fatigue. These reactions are generally mild and resolve on their own. Severe allergic reactions are rare.

Contraindications

Zoster vaccines are contraindicated in individuals with a history of severe allergic reaction to any component of the vaccine or to a previous dose of the vaccine. The live vaccine is also contraindicated in individuals with a weakened immune system.

Future Directions

Research continues to focus on the long-term effectiveness of zoster vaccines and their potential use in younger populations. Studies are also exploring the possibility of combining the zoster vaccine with other vaccines to reduce the number of injections required for adults.