Use of SMS-linked electronic surveys for COVID-19 case investigation and contact tracing — Marin County, CA, USA

Julia M. Janssen, Alana McGrath, Rochelle Ereman, Patrick K. Moonan, John E. Oeltmann, Matthew Willis, Stephen A. McCurdy

Research output: Contribution to journalArticlepeer-review


Objectives: We sought to quantify the proportion of contacts reported by persons with COVID-19 through a short message service (SMS)-linked survey in comparison to the proportion of contacts reported during a follow-up phone-interview. We also sought to assess improvement in contact tracing timeliness associated with sending SMS-linked surveys. Study design: During December 4–15, 2020, persons identified as COVID-19 cases whose data was entered into Marin County's contact tracing database on even days received a SMS-linked survey and persons whose data was entered on odd days did not; all were called for case investigation and contact tracing. Chi-square test and Fisher's exact test were used to compare demographic data. Chi-square test was used to contrast categorical outcomes, and Wilcoxon's rank-sum test was used for continuous outcomes. Results: Among 350 SMS-linked survey recipients, 85 (24%) responded and 4 (1%) reported contacts using the survey; an additional 303 contacts were reported during phone interviews. Without phone interviews, 99% of reported contacts would have been missed. There was no meaningful difference between study arms in the proportion of contacts notified within 48 h. Conclusions: This SMS-linked survey had low participation and was not useful for identifying contacts. Phone interviews remained crucial for COVID-19 contact tracing.

Original languageEnglish (US)
Article number100170
JournalPublic Health in Practice
StatePublished - Nov 2021
Externally publishedYes


  • Case investigation
  • Contact tracing
  • COVID-19
  • Short message service (SMS)
  • Surveys

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health Policy


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