# Observed negative vaccine effectiveness could be the canary in the coal mine for biases in observational COVID-19 studies

> Research article (International Journal of Infectious Diseases, 2023) · cited 32× · AI/ML

**Wikidata**: [openalex:W4361011569](https://www.wikidata.org/wiki/openalex:W4361011569)  
**Source**: https://4ort.xyz/entity/observed-negative-vaccine-effectiveness-could-be-the-canary-in-the-coal-mine-for-biases-in-observational-covid-19-studie