Smita Kothari (United States of America)
Merck & Co. Inc. Center for Observational and Real-world EvidencePresenter of 3 Presentations
METHODOLOGIES USED FOR ASSESSING IMPACT AND EFFECTIVENESS OF THE QUADRIVALENT HUMAN PAPILLOMAVIRUS VACCINE (4VHPV) ON HPV-RELATED OUTCOMES: A SYSTEMATIC LITERATURE REVIEW (ID 331)
Abstract
Introduction
Finding data and appropriate methods for measuring impact#and vaccine effectiveness (VE)# of the human papillomavirus (HPV) vaccine is not trivial. We revieweddata sources and methods used in vaccine impact and VE studies regarding anogenital warts (AGW), cervical lesions and HPV infection.
Methods
A systematic literature review of Medline and Embase was conducted for studies (2016-2019) evaluating the impact or VE of the 4-valent HPV vaccine. Data sources and methods used were categorized by study outcome.
Results
Of 2,428 publications screened, 59 papers (28 impact, 22 VE, 9 both) were included (Table 1). Data sources varied by outcome: electronic health records/claims databases for AGW (10/14, 71.4%); cancer screening registries for cervical lesions (15/20, 75.0%); surveys for HPV infection (23/25, 92.0%). The 42 studies collecting vaccination history relied primarily on self-reporting (21/42, 50.0%) or vaccine registries (13/42, 33.3%). Self-reported vaccination was validated in 5/21 studies (23.8%) using vaccine registries mostly. Coded outcomes were validated through medical chart review in 5/14 (35.7%) studies.
Conclusions
A large variety of data sources and methods are being used to assess the impact and VE of 4vHPV, with a heavy reliance on registries and ecological designs.The use of appropriate negative controls, adjustment for confounders, and validation of vaccination status and outcome can be important tools to mitigate potential biases.
UNDERSTANDING DATA SYSTEMS THAT ENABLE ASSESSMENT OF THE IMPACT OF HPV VACCINATION IN HIGH-INCOME COUNTRIES (ID 1331)
Webcast
AN ASSESSMENT OF THE FACTORS THAT CONTRIBUTE TO RESILIENCE IN HPV VACCINATION SYSTEMS AROUND THE WORLD: A LITERATURE REVIEW (ID 1169)
- Caroline Huber (United States of America)
- Suepattra G. May (United States of America)
- Glorian P. Yen (United States of America)
- Meaghan Roach (United States of America)
- Emily Boller (United States of America)
- Isha Desai (United States of America)
- Chime Nnadi (United States of America)
- Ciara O'Rourke (United States of America)
- Michele Sausser (United States of America)
- Anupam Jena (United States of America)
- Smita Kothari (United States of America)
Abstract
Introduction
In recent years, shocks, or external stresses or challenges to vaccination systems (e.g. vaccine hesitancy, safety concerns), have resulted in drops in vaccination rates of routinely recommended vaccines. Furthermore, these shocks have led to the resurgence of previously well-contained vaccine-preventable diseases. The capacity of health entities and local stakeholders to effectively respond to such shocks, maintain core functions when shocks arise, and quickly adapt to changing circumstances helps to demonstrate a health system’s resilience. This study assessed the factors that may impact vaccination systems’ resilience within the context of HPV vaccination.
Methods
A targeted literature review was conducted to identify peer-reviewed, grey literature, and web publications from 2011-2019 related to health or vaccination systems’ resilience and HPV vaccine-related safety concerns and/or crises introducing unanticipated shocks to systems.
Results
We screened 143 publications, of which 107 were included for full review. Several publications focused on factors that support or erode health systems’ resilience in the face of shocks, but few focused specifically on impacts to vaccination systems. Several highlighted recent shocks to HPV vaccination programs in Japan, Ireland, India and Denmark, which were attributed to alleged vaccine safety concerns and led to subsequent vaccine hesitancy. Denmark’s multi-stakeholder response to the shock demonstrated concepts associated with resilience (e.g. adaptability and coping), enabling post-shock recovery of vaccination rates. Conversely, the Japanese government ceased proactively recommending the vaccine, which has led to a vaccination rate of around 1% in females born after 2001.
Conclusions
A comprehensive understanding of the factors associated with vaccination systems’ resilience is important for addressing vaccine hesitancy. Using recent HPV vaccine-related shocks as a case study highlights the imperative for vaccination system stakeholders to work to instill trust and maintain vaccination coverage rates, while adapting and responding to the political, social, and economic impacts that unanticipated shocks can produce.