COVID-19 can cause asymptomatic and mild illness, particularly among young, healthy populations. This CDC investigation of an outbreak of COVID-19 among a group of college-aged travelers and their contacts demonstrated that 28% had positive SARS-CoV-2 RT-PCR test results, approximately one fifth of whom were asymptomatic when tested.
In March, 2020, the University of Texas Health Austin COVID-19 Center launched an outbreak investigation after three symptomatic students tested positive for SARS-CoV-2 test. Contact tracing linked the students’ infections to a spring break trip to Cabo San Lucas, Mexico, during March 14–19. Among 231 persons tested for SARS-CoV-2 in the investigation, 64 (28%) had positive test results, including 60 (33%) of 183 Cabo San Lucas travelers, one of 13 (8%) household contacts of Cabo San Lucas travelers, and three (9%) of 35 community contacts of Cabo San Lucas travelers. Approximately one fifth of persons with positive test results were asymptomatic; no persons needed hospitalization, and none died.
This COVID-19 outbreak among a young, healthy population with no or mild symptoms was controlled with a coordinated public health response that included rapid contact tracing and testing of all exposed persons. A coordinated response with contact tracing and testing of all contacts, including those who are asymptomatic, is important in controlling future COVID-19 outbreaks that might occur as schools and universities consider reopening.