Austin public health authorities and the University of Texas at Austin have contacted every "spring breaker onboard the plane using flight manifests from the Center for Disease Control and Prevention", the city's statement said.
Around 70 people in their 20s are under investigation in Austin, Texas, for possible infection with the coronavirus that causes COVID-19 after they chartered a plane for a vacation to Cabo San Lucas, Mexico, last month.
A group about 70 people in their 20s took a chartered flight from Austin to Cabo San Lucas a week and a half ago despite recent warnings against unnecessary worldwide travel from the government.
Those in the cluster with confirmed cases are self-isolating, while many others are being tested and are under quarantine, the city said.
The department said four people with confirmed cases did not have any symptoms.
"The university is working closely with Austin Public Health to assist in contact tracing", a spokesperson for UT Austin told PEOPLE in a statement on Tuesday.
Dozens who haven't tested positive remain under a public health investigation. "The Department of State Health Services has been notified", Austin public health officials said in a statement.
Mexico was not under a federal travel advisory at the time of the trip, but the Centers for Disease Control and Prevention was recommending a stop to all non-essential global travel. Even those who don't get severely ill themselves pose a risk of spreading the disease to others who may be more vulnerable. Two people have died from COVID-19 in the county.
Although most of the serious cases of covid-19 occur in older people and those with underlying health conditions, young and otherwise healthy adults have also been hospitalized with the coronavirus.
The development comes as spring breakers faced backlash for going on vacation despite the viral pandemic. "I would like to sincerely apologize for the insensitive comment I made in regards to COVID-19 while I was on spring break", he said. "mtvU Spring Break" starts airing March 31st on mtvU. An individual who is asymptomatic could spread the virus to many others, including some who may have much more severe reactions. In fact, figures as of March 16 show that 20% of all COVID-19 hospitalizations in the USA are of people aged 20-44.