A COVID-19 outbreak at a Chicago university emerged after spring break, with a majority of cases among students who recently traveled, according to Centers for Disease Control and Prevention (CDC) research.
The university confirmed 158 COVID-19 cases among students between March 15-May 3, with 72.2 percent of infected students living in on-campus dormitories, a CDC study published Thursday found.
Out of the 140 students interviewed, 63.6 percent said they recently traveled outside of Chicago during spring break, with travel extending across seven countries and 23 states, and 40.7 percent reported “indoor social exposures.” Two were evaluated in the emergency department, but none of the students were hospitalized or died.
The Chicago Department of Public Health (CDPH) learned of the outbreak in April, not long after the urban university’s spring break, which lasted from March 20-29.
At the time, most university-aged students did not qualify to get the COVID-19 vaccine yet, so only three students had been fully vaccinated before their infection. More than 66 percent of infected students were unvaccinated, and 30.7 percent were partially vaccinated.
But the university had implemented precautions, with all students mandated to report any positive COVID-19 tests and students living on campus required to undergo weekly testing. The university had also advised students not to travel during spring break.
The urban school recommended on-campus students stay in their dormitories for a week following the break and refrain from returning to in-person classes until getting tested.
After discovering the outbreak, the university launched a stay-at-home order for students living on-campus with all-remote classes and banned gatherings. It lifted the order 14 days later after a few cases arose.
Researchers sequenced 104 samples of the virus and determined a majority came from the B.1.1.222 – a strain thought to have emerged in the U.S. or Mexico. This variant was “not widely detected in Chicago before or after this outbreak,” the agency’s Morbidity and Mortality Weekly Report (MMWR) said.
The sequences of the B.1.1.222 variant were very similar, meaning the strain “likely” came from a single source, and “most closely” resembled strains from California, where eight students with the strain had traveled.
More than 20 percent of the cases were traced to the alpha strain that was spreading in the U.S. at the time.
“These results demonstrate the potential for COVID-19 outbreaks on university campuses after widespread student travel during breaks, at the beginning of new school terms, and when students participate in indoor social gatherings,” the report said.
Based on the study, the CDC suggested that colleges and universities encourage vaccination, dissuade unvaccinated students from traveling, conduct screening among unvaccinated students after breaks, promote masking and institute testing for students based on the community’s transmission levels.
The agency highlighted the importance of these measures as the delta variant dominates and continues to wreak havoc in the country.
The CDC did warn the data could be incomplete as some infected students refused to be interviewed, and some countered other students’ claims that they traveled together. The mandatory testing was also only for on-campus students, leaving those living off-campus out of the picture.