Effects of herpes zoster infection, antivirals and vaccination on risk of developing dementia: A systematic review and meta-analysis
Bibliographic record
Abstract
Herpes zoster (HZ) is a neurotropic virus. We aimed to evaluate the association of HZ infection, protective effects of antiviral treatment or vaccination on dementia. A systematic search of PubMed, MEDLINE, EMBASE, Scopus, Web of Science, CINAHL, and Cochrane CENTRAL was performed from January 1, 1996, to October 31, 2024. Observational studies evaluating HZ infection, antivirals, or vaccination and dementia risk were selected. Risk of bias was examined with the Newcastle-Ottawa scale. A random-effects meta-analysis was performed, with the rate ratio (RR) and corresponding 95% confidence intervals (CIs) being pooled for dementia. Presence of heterogeneity was assessed with I2, and differences by study-level characteristics were estimated using subgroup meta-analysis and meta-regression. Eighteen studies (N = 9.4 million) were included. Infection was associated with elevated risk of dementia (RR 1.14; 95% CI: 1.04, 1.25, I2 = 98%); this remained significant in the sensitivity analysis when the two case-control studies were removed (RR 1.17; 95% CI: 1.06, 1.30, I2 = 98%). Subgroup analysis based on sex, age, study population, bias scores, type of dementia or HZO did not show statistically significant differences in risk. Treatment with antivirals showed a small effect (RR 0.84; 95% CI: 0.71, 0.99, I2 = 73%), but prophylaxis with HZ vaccination was associated with a significantly lower risk (RR 0.68; 95% CI: 0.56, 0.83, I2 = 99%). We report a slightly raised dementia risk after HZ infection and reduced risks after antiviral treatment and prevention with vaccination. However, results should be interpreted with caution due to significant heterogeneity in pooled analyses.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.014 | 0.030 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.024 | 0.035 |
| Bibliometrics | 0.008 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".