After a significant viral outbreak before winter break in December, COVID-19 infection levels at Cornell University had markedly declined, as the omicron surge receded, and students returned to campus for the spring semester.

However, as new case totals begin to tick up in the state of New York, the campus is once again reporting a viral resurgence. This week, Cornell elevated its COVID-19 alert system to “yellow,” indicating that transmission is rising, and prevalence of the virus is above predicted levels.

Between March 17 and March 23, Cornell recorded 515 positive COVID-19 infections among students, staff and faculty, according to data from the university.

“COVID-19 cases on the Ithaca campus are increasing beyond our predictions, indicating a substantial prevalence of the virus on campus,” Provost Michael Kotlikoff said in a statement on Wednesday. “This rising transmission is likely due to a number of factors, including relaxing mask requirements, the emergence of the BA.2 variant, and increased social activities.”

Data shows 97% of the student population is vaccinated, while 92% of those eligible are boosted.

At this time, all unvaccinated or unboosted students, faculty, and staff are required to participate in surveillance testing. Cornell provides symptomatic test kits to community members who are experiencing mild to moderate symptoms suggestive of COVID-19.

“The majority of positive cases being reported on campus are from symptomatic testing, which tells us that there are even more asymptomatic cases within our community,” Kotlikoff wrote.

The increase comes less than two weeks after the school dropped its mask mandate for most locations, though community members are still required to wear masks when in certain settings, such as classrooms and laboratories, at health care and testing facilities, and on public transportation.

Given the resurgence, the university strongly encourages community members to get tested before and after spring break, which is not for another week.

With increasing viral transmission occurring overseas, federal officials have been warning that the U.S. is likely to see an uptick in COVID-19 cases in the weeks to come, as the presence of the omicron subvariant, BA.2, spreads across the country.

Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said Wednesday her agency is “carefully” watching New England and New York City for increases of the BA.2 variant after they found slight increases in the presence of COVID-19 in wastewater surveillance.

“Currently, we’re seeing a modest uptick of sites reporting an increase of virus levels in wastewater in some communities. In fact, over the past two weeks we have seen increasing wastewater signals in New York City and parts of New England, where we are now seeing increases in cases and some increased hospitalizations,” Walensky said during a White House COVID-19 briefing.

Walensky said officials have been focused largely on hospitalization metrics, to guide potential future guidance on masking and restriction measures.

“If cases do go up, we have the framework to implement additional layers of prevention strategies at the local level to swiftly protect individuals and communities,” Walensky said.

Many experts have been warning that the virus may be already spreading rapidly across the country.

Dozens of states have moved to shutter public testing sites, with more at-home COVID-19 tests now available in pharmacies, and through the federal testing program. Most Americans are not reporting their results to officials, and thus, experts said infection totals are likely significantly undercounted.

Nationwide, BA.2, now accounts for more than a third of new COVID-19 cases. Many top health officials, including Walensky and Dr. Anthony Fauci, the nation’s top infectious disease expert, have said that they anticipate that over the next few weeks, BA.2 will become the predominant variant in the U.S.

Although breakthrough COVID-19 infections surged during the omicron wave, data from the CDC shows vaccines still dramatically reduced the risk of requiring hospitalization or dying of the virus.

In January, unvaccinated adults were 9 times more likely to die of COVID-19, compared to vaccinated individuals, and six times more likely to require hospitalization.

Additionally, unvaccinated adults were about 21 times more likely to die of COVID-19 in January, and 12 times more likely to require hospitalization, compared to fully vaccinated and boosted adults.