The zoster vaccine is a shot that prevents shingles, a painful rash caused by the reactivation of the chickenpox virus. The only zoster vaccine currently available in the United States is Shingrix, a two-dose recombinant vaccine approved in 2017. An older live vaccine called Zostavax was discontinued in November 2020.
How the Vaccine Works
If you had chickenpox as a child, the virus never fully left your body. It stays dormant in nerve tissue, and as your immune system weakens with age or illness, the virus can reactivate as shingles. Shingrix works by training your immune system to recognize a specific protein found on the surface of the chickenpox virus. This protein is produced in a lab using genetically engineered cells, so the vaccine contains no live virus. A built-in booster ingredient (called an adjuvant) made from plant and bacterial extracts amplifies the immune response, prompting your body to build stronger, longer-lasting protection than it could from the protein alone.
This combination of a targeted viral protein and a powerful immune booster is what sets Shingrix apart from the old Zostavax vaccine, which used a weakened live form of the virus. Shingrix produces a more robust immune response, offers higher protection rates, and can be given to people with weakened immune systems, something the live vaccine could not safely do.
Who Should Get It
The CDC recommends the zoster vaccine for two groups:
- Adults 50 and older, regardless of whether they remember having chickenpox or have already had a shingles episode.
- Adults 19 and older with weakened immune systems due to conditions like HIV, cancer, organ transplants, or medications that suppress immune function.
If you previously received Zostavax, you should still get vaccinated with Shingrix. If you’ve already had shingles, the vaccine helps prevent future episodes. There is no need to get tested for prior chickenpox infection before vaccination.
Dosing Schedule
Shingrix requires two doses. For most healthy adults 50 and older, the second shot is given 2 to 6 months after the first. For immunocompromised adults, the window can be shortened to 1 to 2 months between doses when there’s a benefit to completing the series quickly, such as before starting a treatment that will further suppress the immune system.
If more than 6 months pass between your first and second dose, you don’t need to start over. Just get the second dose as soon as you can.
Common Side Effects
Shingrix is known for causing noticeable side effects, more so than many routine vaccines. About 78% of recipients report pain at the injection site, and common reactions include redness, swelling, muscle pain, fatigue, headache, shivering, fever, and upset stomach. These are signs your immune system is responding to the vaccine, not signs of illness.
Roughly 1 in 10 people experience reactions strong enough to interfere with normal daily activities for a day or two. These “grade 3” reactions include severe injection-site soreness and systemic symptoms like significant muscle pain or fatigue. Overall, about 17% of vaccinated people reported at least one reaction in this category. The side effects are temporary, typically resolving within one to three days, and are considerably more common after the second dose than the first.
Planning your vaccination for a day when you can rest the following day is a practical move, especially for the second shot.
Why Shingles Prevention Matters
Shingles itself is unpleasant: a blistering, burning rash that usually wraps around one side of the torso or face and lasts two to four weeks. But the real concern is what can follow. A complication called postherpetic neuralgia causes nerve pain that lingers for months or even years after the rash heals. The risk of both shingles and its complications rises sharply with age, which is why vaccination is recommended starting at 50.
Shingles can also cause eye damage if it affects the facial nerve, and in rare cases can lead to hearing loss, bacterial skin infections, or neurological problems. Vaccination dramatically reduces the likelihood of all of these outcomes.
What Happened to Zostavax
Zostavax, the original shingles vaccine, was available from 2006 until November 18, 2020, when it was pulled from the U.S. market. It used a weakened live virus, which meant it couldn’t be given to immunocompromised patients and offered lower, shorter-lasting protection. Once Shingrix proved superior in clinical trials, the CDC designated it the preferred vaccine in 2017, and Zostavax was eventually discontinued entirely. If you received Zostavax years ago, its protection has likely waned, and switching to the Shingrix series is recommended.