New paper (Liu): COVID-19 Vaccination and Changes in Contact Patterns
New paper led by Carol Liu in Epidemics: The Effect of COVID-19 Vaccination on Change in Contact and Implications for Transmission. This analysis used a longitudinal cohort sampled from United States households that measured contact rates, risk mitigation, and COVID-19 vaccination status between August 2020 and April 2022. Contact rates increased across survey rounds in all sociodemographic groups, though unvaccinated participants reported persistently higher rates. In a multilevel generalized linear mixed effects model, individuals who newly completed a primary vaccine series reported an additional 1.93 contacts (95% CI 0.27 to 3.59) relative to those who remained unvaccinated. Transmission estimates from observed contact rates suggest these increases were not fully offset by vaccine protection against infection.
