ORIGINAL RESEARCH article

Front. Public Health

Sec. Infectious Diseases: Epidemiology and Prevention

Volume 13 - 2025 | doi: 10.3389/fpubh.2025.1497390

Real-World Impact of COVID-19 Vaccination, Household Exposure, and Circulating SARS-CoV-2 Variants on Infection Risk and Symptom Presentation in a U.S./Mexico Border Community

Provisionally accepted
Ariel  CohenAriel Cohen1Breanna  ReyesBreanna Reyes2Maria Linda  BurolaMaria Linda Burola2Angel  LomeliAngel Lomeli2*Arleth  A EscotoArleth A Escoto2Linda  SalginLinda Salgin3Borsika  RabinBorsika Rabin4,5Nicole  A StadnickNicole A Stadnick2,5,6Ilya  ZaslavskyIlya Zaslavsky7Robert  TukeyRobert Tukey1Louise  LaurentLouise Laurent2Marva  SeifertMarva Seifert1
  • 1University of California, San Diego, La Jolla, California, United States
  • 2UC San Diego Health, University of California, San Diego, San Diego, United States
  • 3San Ysidro Health Center, San Diego, California, United States
  • 4Herbert Wertheim School of Public Health and Human Longevity Science, University of California, San Diego, La Jolla, California, United States
  • 5Altman Clinical and Translational Research Institute, School of Medicine, University of California, San Diego, La Jolla, California, United States
  • 6Child and Adolescent Research Center, San Diego, United States
  • 7San Diego Supercomputer Center, Jacobs School of Engineering, University of California, San Diego, La Jolla, California, United States

The final, formatted version of the article will be published soon.

BackgroundSan Ysidro, a densely populated primarily Latino community near the U.S./Mexico border, reported the highest rate of COVID-19 infection in San Diego County. In this increased infection risk environment, we explored the impact of COVID-19 vaccine status, household exposure, and primary circulating SARS-CoV-2 variant on the probability of infection and symptom presentation while controlling for temporal and sociodemographic factors. MethodsData were collected as part of CO-CREATE (Community-Driven Optimization of COVID-19 Testing to Reach and Engage underserved Areas for Testing Equity), a collaborative implementation study between University of California San Diego, a local Federally Qualified Health Center, and the Global Action Research Center. Self-reported sociodemographic factors, household exposure, vaccine status, and symptoms were extracted from a cross-sectional questionnaire completed by participants; PCR test results were used for analysis. Multi-level logistic regression, to account for repeat testing, was used to estimate the impact of self-reported vaccination status on COVID-19 household transmission. Logistic regression was used to characterize symptoms associated with predominate circulating SARS-CoV-2 variants.ResultsBetween May 2021 and March 2023, 11,412 PCR test results from 6,032 participants were analyzed. Individuals who were vaccinated and had a household exposure were 3.5 times (aOR 3.5 [95% CI 2.7, 4.6]) more likely to be PCR positive compared to individuals who were vaccinated and reported no household exposure; and individuals who were unvaccinated and reported a household exposure were 9.1 times (aOR 9.1 [95% CI 5.3, 15.5]) more likely to be PCR positive compared to individuals who were vaccinated and reported no household exposure. These results were obtained after adjusting for variant wave, age, language spoken, previous infection status, symptom status, and employment. Symptoms varied by predominate circulating SARS-CoV-2 variant, highlighting the impact of variant on disease presentation and potential vaccine efficacy. ConclusionCOVID-19 vaccination was associated with a reduced risk of COVID-19 infection after household exposure, highlighting the importance of equitable access to COVID-19 vaccines, specifically in communities experiencing higher infection rates. Our findings also underscore the necessity for enhancing workplace safety protocols, addressing language-specific considerations, and being cognizant of differing symptom presentation by variant.

Keywords: Household Exposure, COVID-19 vaccination, COVID-19 positivity, Underserved Latino Community, SARS-COV-2 variants

Received: 16 Sep 2024; Accepted: 19 May 2025.

Copyright: © 2025 Cohen, Reyes, Burola, Lomeli, Escoto, Salgin, Rabin, Stadnick, Zaslavsky, Tukey, Laurent and Seifert. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Angel Lomeli, UC San Diego Health, University of California, San Diego, San Diego, United States

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