Variant Specific Treatment Effects with Applications in Vaccine Studies

Fuente: arXiv
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Autori principali: Perenyi, Gellert, Stensrud, Mats J.
Natura: Preprint
Pubblicazione: 2024
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author Perenyi, Gellert
Stensrud, Mats J.
author_facet Perenyi, Gellert
Stensrud, Mats J.
contents Pathogens usually exist in heterogeneous variants, like subtypes and strains. Quantifying treatment effects on the different variants is important for guiding prevention policies and treatment development. Here we ground analyses of variant-specific effects on a formal framework for causal inference. This allows us to clarify the interpretation of existing methods and define new estimands. Unlike most of the existing literature, we explicitly consider the (realistic) setting with interference in the target population: even if individuals can be sensibly perceived as iid in randomized trial data, there will often be interference in the target population where treatments, like vaccines, are rolled out. Thus, one of our contributions is to derive explicit conditions guaranteeing that commonly reported vaccine efficacy parameters quantify well-defined causal effects, also in the presence of interference. Furthermore, our results give alternative justifications for reporting estimands on the relative, rather than absolute, scale. We illustrate the findings with an analysis of a large HIV1 vaccine trial, where there is interest in distinguishing vaccine effects on viruses with different genome sequences.
format Preprint
id arxiv_https___arxiv_org_abs_2408_07560
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Variant Specific Treatment Effects with Applications in Vaccine Studies
Perenyi, Gellert
Stensrud, Mats J.
Applications
Pathogens usually exist in heterogeneous variants, like subtypes and strains. Quantifying treatment effects on the different variants is important for guiding prevention policies and treatment development. Here we ground analyses of variant-specific effects on a formal framework for causal inference. This allows us to clarify the interpretation of existing methods and define new estimands. Unlike most of the existing literature, we explicitly consider the (realistic) setting with interference in the target population: even if individuals can be sensibly perceived as iid in randomized trial data, there will often be interference in the target population where treatments, like vaccines, are rolled out. Thus, one of our contributions is to derive explicit conditions guaranteeing that commonly reported vaccine efficacy parameters quantify well-defined causal effects, also in the presence of interference. Furthermore, our results give alternative justifications for reporting estimands on the relative, rather than absolute, scale. We illustrate the findings with an analysis of a large HIV1 vaccine trial, where there is interest in distinguishing vaccine effects on viruses with different genome sequences.
title Variant Specific Treatment Effects with Applications in Vaccine Studies
topic Applications
url https://arxiv.org/abs/2408.07560