12. Modeled Impact of the COVID-19 Pandemic and Associated Reduced Adult Vaccinations on Herpes Zoster in the United States

Abstract Background During the COVID-19 pandemic, adult vaccination in the United States (US) decreased substantially in 2020. Unlike other vaccine-preventable diseases where individuals may have experienced reduced risk due to COVID-related mitigation efforts (e.g., lockdown restrictions, use of face masks), individuals remained at risk of herpes zoster (HZ). This study projects the impact of reduced recombinant zoster vaccine (RZV) use on HZ cases and complications in the US. Methods A multi-cohort Markov model estimated the impact of missed RZV vaccinations, by comparing scenarios with and without missed vaccinations between Apr-Dec 2020, on cases of HZ, postherpetic neuralgia (PHN), and quality-adjusted life-years (QALYs) among US adults aged ≥ 50 years. Epidemiology, RZV efficacy, and utility inputs were obtained from standard US sources, clinical trial data, and published literature. Missed doses were estimated using data on RZV doses and an assumed 43% reduction in RZV vaccinations during the pandemic, based on publicly available data. Deterministic sensitivity and scenario analyses were conducted. Results In 2020, approximately 21 million (M) RZV distributed doses were expected, including an estimated 9.2M RZV series initiations in Apr-Dec. An estimated 3.9M RZV series initiations were missed, resulting in 31,945 projected HZ cases, 2,714 PHN cases, and 610 lost QALYs projected over a 1-year follow up. If individuals with missed RZV initiations remain unvaccinated in 2021, avoidable HZ cases will increase to 63,117 over 2 years. Further, if the same number of RZV initiations are missed in 2021, 95,062 avoidable HZ cases are expected. In a sensitivity analysis assuming 30% RZV reduction, 18,020 avoidable HZ cases and 1,531 PHN cases were observed over 1 year. Conclusion Adding to the substantial COVID-19 infection-related morbidity and mortality, reduced RZV use during the pandemic resulted in further burden from avoidable HZ cases. Health care providers should continue to emphasize the importance of vaccination against HZ and other preventable diseases during the pandemic. Funding GlaxoSmithKline Biologicals SA (GSK study identifier: [VEO-000222]). Acknowledgement Business & Decision Life Sciences c/o GSK (Coordination: Quentin Rayée). Disclosures Elizabeth M. La, PhD, The GSK group of companies (Employee, Shareholder) Desmond Curran, PhD, The GSK group of companies (Employee, Shareholder) Ahmed Salem, MSc, The GSK group of companies (Employee) David Singer, PharmD, MS, The GSK group of companies (Employee) Nicolas Lecrenier, Ing, PhD, The GSK group of companies (Employee, Shareholder) Sara Poston, PharmD, The GSK group of companies (Employee, Shareholder)


Conclusion.
A very high rate of PLWH received vaccine, far exceeding local and national benchmarks, with EMR data unlikely to have fully captured all vaccines. The role of the COVID-19 pandemic in vaccine amongst PLWH is not yet known. While older age was associated with vaccine in adjusted analysis, the number of unvaccinated patients was small, confidence intervals wide, and associations consequently weak. Larger studies are needed to further investigate factors associated with vaccine receipt amongst PLWH.

Session: P-02. Adult Vaccines
Background. During the COVID-19 pandemic, adult vaccination in the United States (US) decreased substantially in 2020. Unlike other vaccine-preventable diseases where individuals may have experienced reduced risk due to COVID-related mitigation efforts (e.g., lockdown restrictions, use of face masks), individuals remained at risk of herpes zoster (HZ). This study projects the impact of reduced recombinant zoster vaccine (RZV) use on HZ cases and complications in the US.

Methods.
A multi-cohort Markov model estimated the impact of missed RZV vaccinations, by comparing scenarios with and without missed vaccinations between Apr-Dec 2020, on cases of HZ, postherpetic neuralgia (PHN), and quality-adjusted life-years (QALYs) among US adults aged ≥ 50 years. Epidemiology, RZV efficacy, and utility inputs were obtained from standard US sources, clinical trial data, and published literature. Missed doses were estimated using data on RZV doses and an assumed 43% reduction in RZV vaccinations during the pandemic, based on publicly available data. Deterministic sensitivity and scenario analyses were conducted.
Results. In 2020, approximately 21 million (M) RZV distributed doses were expected, including an estimated 9.2M RZV series initiations in Apr-Dec. An estimated 3.9M RZV series initiations were missed, resulting in 31,945 projected HZ cases, 2,714 PHN cases, and 610 lost QALYs projected over a 1-year follow up. If individuals with missed RZV initiations remain unvaccinated in 2021, avoidable HZ cases will increase to 63,117 over 2 years. Further, if the same number of RZV initiations are missed in 2021, 95,062 avoidable HZ cases are expected. In a sensitivity analysis assuming 30% RZV reduction, 18,020 avoidable HZ cases and 1,531 PHN cases were observed over 1 year.
Conclusion. Adding to the substantial COVID-19 infection-related morbidity and mortality, reduced RZV use during the pandemic resulted in further burden from avoidable HZ cases. Health care providers should continue to emphasize the importance of vaccination against HZ and other preventable diseases during the pandemic.

The Efficacy and Effectiveness of Pneumococcal Vaccines against Pneumococcal Pneumonia among Adults: A Systematic Review and Meta-Analysis
Lana Childs, MPH 1 ; Miwako Kobayashi, MD, MPH 2 ; Jennifer Loo Farrar, MPH 2 ; Tamara Pilishvili, PhD 3 ; 1 National Foundation for the Centers for Disease Control and Prevention, Inc., Atlanta, Georgia; 2 Centers for Disease Control and Prevention, Atlanta, GA; 3 Centers for Disease Control and Prevention, Atlanta, GA, USA, Atlanta, Georgia

Session: P-02. Adult Vaccines
Background. Two pneumococcal vaccines are currently recommended for use in U.S. adults: 23-valent pneumococcal polysaccharide vaccine (PPSV23) and 13-valent pneumococcal conjugate vaccine (PCV13). Recommendations for adult PCV13 use were supported by a large randomized-controlled trial (RCT) demonstrating PCV13 efficacy against pneumococcal pneumonia (PnPn) and vaccine-type (VT) PnPn in older adults. New pneumococcal conjugate vaccines are expected to be licensed for adults in late 2021 and recommendations for use among adults will be reviewed and revised, as needed. We conducted a systematic review to summarize evidence on the vaccine efficacy and effectiveness (VE) of PPSV23 and PCV13 against PnPn among adults.
Methods. We conducted a search of literature published from 1998 to February 2021 on PCV13 and PPSV23 VE studies using eight reference databases. Studies targeting adults with immunocompromising conditions were excluded. VE results with 95% confidence intervals (CI) were abstracted and stratified by vaccine product, outcome evaluated (PnPn and VT PnPn), study design, and effect measure. When applicable, random effects models were used to estimate pooled VE and I-squared statistic was reported to assess heterogeneity.