If you're 50 or older and your immune system is healthy, getting two shots of this special shingles vaccine, two months apart, cuts your chance of getting shingles by almost all the way down—like going from a 10% risk to less than 0.3%.
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The claim cites a specific percentage reduction (97.2%) and a defined follow-up period (3.2 years), which matches the design of a large, randomized, placebo-controlled phase 3 trial (e.g., ZOE-50 and ZOE-70). These trials are designed to establish causal efficacy with high precision. The population is clearly defined (non-immunosuppressed adults ≥50), and the outcome (herpes zoster incidence) is objective and clinically validated. The magnitude of effect is consistent with published data from the Shingrix trials, making the claim both precise and evidence-based.
More Accurate Statement
“In adults aged 50 years and older without immunosuppression, administration of two doses of the adjuvanted herpes zoster subunit vaccine (HZ/su) spaced two months apart reduces the incidence of herpes zoster by 97.2% over a mean follow-up period of 3.2 years, as demonstrated in a randomized, double-blind, placebo-controlled clinical trial.”
Context Details
Domain
medicine
Population
human
Subject
Adults aged 50 years and older without immunosuppression
Action
reduces
Target
the risk of herpes zoster by 97.2% over a mean follow-up of 3.2 years
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Efficacy of an adjuvanted herpes zoster subunit vaccine in older adults.
This study gave older adults two shots of a special herpes vaccine two months apart and found it cut their chance of getting shingles by 97.2% — exactly what the claim says.