Zoster risk: immunity wanes after household exposure

  • Forbes H, et al
  • BMJ
  • 22 ene. 2020

  • de Liz Scherer
  • Clinical Essentials
El acceso al contenido completo es sólo para profesionales sanitarios registrados. El acceso al contenido completo es sólo para profesionales sanitarios registrados.

Takeaway

  • Household exposure to varicella appears to reduce herpes zoster (HZ) risk by ~30% within 2 years and by 27% in 10-20 years postexposure.

Why this matters

  • Exogenous varicella boosting in adults provides incomplete immunity against HZ.​​
  • Consider Zostavax (zoster vaccine live) in adult patients aged ≥50 years.

Key results

  • 9604 adults with HZ.
  • Median age, first varicella exposure: 41.1 (interquartile range, 33.1-51.3) years.
    • 1.2% (118) severely immunosuppressed at exposure. 
  • Adjusted HZ incidence ratio (IR),
  • IR, 0.67 (95% CI, 0.62-0.73).
  • Adjusted HZ IR, 10-20 years postexposure vs baseline:
    • IR, 0.73 (95% CI, 0.62-0.87).
  • Exposure effect varied by sex:
    • 10-20 years: IR, 0.59 men vs 0.82 women (P<.001>
  • Repeated household varicella exposure did not confer greater risk reduction vs first exposure.
  • Study design

    • Self-controlled case series analysis of relative risk of HZ over time following exposure to household contact with varicella based on UK electronic health records (EHRs).
    • Funding: UK Medical Research Council; others.

    Limitations

    • Varicella underestimated in UK EHRs.
    • Household exposure misclassifications; bias toward the null.
    • Uncaptured occupational exposure; bias away from the null. 
    • Underpowered to detect boosting effect in immunocompromised.