Challenges of evaluating and modelling vaccination in emerging infectious diseases

Abstract

Outbreaks of emerging pathogens pose unique methodological and practical challenges for the design, implementation, and evaluation of vaccine efficacy trials. Lessons learned from COVID-19 highlight the need for innovative and flexible study design and application to quickly identify promising candidate vaccines. Trial design strategies should be tailored to the dynamics of the specific pathogen, location of the outbreak, and vaccine prototypes, within the regional socioeconomic constraints. Mathematical and statistical models can assist investigators in designing infectious disease clinical trials. We introduce key challenges for planning, evaluating, and modelling vaccine efficacy trials for emerging pathogens.

Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status

“…Myriad factors preclude our ability to make direct comparisons of vaccine effectiveness across studies, including differences in the study population (eg, age, comorbidities, and serostatus), location, diagnostic procedures and tools, definition of vaccination status (eg, time elapsed since vaccination or dosage) (eTable 8 in the Supplement ), follow-up duration, viral variants, vaccine types and coverage rates, intensity of the epidemic, community behavior, and use of nonpharmaceutical interventions (masks and social distancing). 87 For example, in this analysis Singanayagam et al 42 included households of any size with contacts 5 or more years, whereas Gazit et al 21 restricted to households with only 1 contact other than the index case. Moreover, Ng et al 37 in Singapore reported that all identified close contacts were placed under a legally binding quarantine for 14 days during which they were not allowed to leave their homes, whereas contacts in other studies may have had a higher risk of infection outside the household.…”

Challenges for modelling interventions for future pandemics

“…The challenge is estimating effectiveness of interventions from noisy data, particularly when multiple interventions are implemented simultaneously (see also Section 4.1). In addition to the challenges involved in designing studies to estimate vaccine efficacy in the context of an evolving pandemic (Madewell et al, 2021), the way the data are collected and recorded also present challenges (Lipsitch and Dean, 2020). For example, vaccination data linked with other health care data or age-stratified vaccination data may not be readily available, thus limiting the opportunity to estimate the impact of the vaccine deployment on symptoms, transmission, risk of hospitalisation and death across different age groups.…”

“…Vaccination (see also Madewell et al, 2021) is a pharmaceutical intervention of primary importance, as it allows conferring protection against infection and/or disease to individuals in a safe and controlled way. Mathematical models can be used to evaluate the effectiveness of vaccination and inform the design of optimal vaccination strategies in terms of feasibility, costs, and disease burden (Matrajt et al, 2021;Bubar et al, 2021).…”

Data analytics during pandemics: a transportation and location planning perspective

“… Identifying key challenges for planning, evaluating, and modeling vaccine efficacy trials for emerging pathogens (Madewell et al. 2021 ) Dynamic COVID-19 vaccine distribution (Albahri et al. 2021 ) Fair distribution of the flu vaccine to potential vaccine recipients during the fall and winter flu season in Iran (Rastegar et al.…”

“…Identifying key challenges for planning, evaluating, and modeling vaccine efficacy trials for emerging pathogens (Madewell et al. 2021 )…”