2284. Ten-year Effectiveness of Live Virus Herpes Zoster Vaccine
Session: Poster Abstract Session: Miscellaneous Vaccines
Saturday, October 6, 2018
Room: S Poster Hall
Background: Although recombinant zoster vaccine (RZV) is recommended preferentially in adults aged ≥50 years in the US, zoster vaccine live (ZVL) remains a recommended vaccine in immunocompetent adults aged ≥60 years and is currently being used in many countries around the world. Assessing the long-term effectiveness of both vaccines is critical for determining vaccine policy, including the optimal age to begin vaccination and the need for and timing of revaccination. We evaluated the long-term effectiveness of ZVL in adults ≥ 60 years old in the US.

Methods: We conducted a retrospective cohort study at Kaiser Permanente Southern California (KPSC). The exposed cohort included KPSC members ≥60 years vaccinated with ZVL during 1/1/2007- 12/31/2014. Three unvaccinated members were matched to each vaccinated member on age, sex, and length of membership. Individuals were followed to 6/30/2017. Electronic health records were used to identify incident herpes zoster (HZ). Effectiveness of ZVL and its 95% confidence interval (CI) at each year following vaccination was estimated.

Results: The number of HZ cases was 7,783 in 923,176 person-years (8.4 per 1,000; 95% CI, 8.2-8.6 per 1,000) among vaccinated persons and 26,813 in 1,964,974 person-years (13.6 per 1,000; 95% CI, 13.5-13.8 per 1,000) among unvaccinated persons. The HZ incidence rate ratio, comparing the vaccinated to the unvaccinated, was 0.62 (95% CI, 0.60-0.63). The effectiveness by year after vaccination decreased each year of follow-up from 65.8% (95% CI, 63.2%-68.2%) in the first year, 49.3% (95% CI, 45.7%-52.6%) in the second, 32.0% (95% CI, 24.1%-39.1%) to 36.8% (95% CI, 32.3%-40.9%) in the 3rd - 6th year, and 22.0% (95% CI, -2.5%- 40.6%) to 23.6% (95% CI, 13.4%-32.7%) in the 7th - 10th year. A similar pattern was seen between those 60-69 years and ≥70 years of age.

Conclusion: The effectiveness of ZVL declined from 66% in the first year to 22% in the 10th year after vaccination. This 10-year effectiveness study of ZVL provides insights into a revaccination strategy and need for a more effective and durable vaccine. Studies of long-term effectiveness of RZV are also warranted.

Hung Fu Tseng, PhD, MPH1, Yi Luo, MS1, Lina S. Sy, MPH1, Kathleen Dooling, MD, MPH2 and Rafael Harpaz, MD2, (1)Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, (2)DVD, Centers for Disease Control and Prevention, Atlanta, GA

Disclosures:

H. F. Tseng, None

Y. Luo, None

L. S. Sy, None

K. Dooling, None

R. Harpaz, None

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