Cornell Omicron Variant Outbreak Shutters the Vaccine-mandated Campus

In 2021, Cornell University shut down its Ithaca, New York, campus after the school reported 930 new cases of COVID-19 —with 276 new positive test results on December 13th alone. Cornell—which has a 97% vaccination rate and tests students for COVID-19 weekly—shifted into a "red: high risk" level alert. Here, experts explained how that outbreak of infection happened.

That level means that there is a "significant increase in incidence with limited quarantine, isolation and/or local hospital capacity." In a message to the school community on December 14, Cornell President Martha E. Pollack said that there has been a "rapid spread" of the virus in the student population—a population that had to adhere to the school's vaccine mandate, which required students to show proof of vaccination or exemption by today. "While faculty and staff case numbers currently remain low, just last evening our COVID-19 testing lab team identified evidence of the highly contagious Omicron variant in a significant number of Monday's positive student samples," Pollack wrote.

Cornell Vice President Joel Malina told NPR that "virtually every case of the Omicron variant [at the school] to date has been found in fully vaccinated students, a portion of whom had also received a booster shot." However, he added, "we have not seen evidence of significant disease in our students to date."

In her letter, Pollack mentioned that there has been some preliminary evidence that the highly transmissible Omicron variant generally causes milder cases, particularly among vaccinated individuals. "However, when you have high transmissibility, you're going to have very high numbers of cases, and so even with lower rates of serious illness, outbreaks must be taken seriously," she wrote.

And so, in response to the jump in cases, the school has canceled all undergraduate activities and moved finals online. A "recognition ceremony" for students graduating this month has been canceled, and students are being "strongly encouraged" to "grab-and-go" at campus dining services. The library, fitness center, and gyms are also closed.

School officials are allowing students who have tested negative for the virus within the past 48 hours to leave campus, but those who have not tested negative in the past 48 hours are being encouraged to get tested ASAP and stay at their school residence until they do. Those who have tested positive are urged to stay in isolation for 10 days.

Visitors and guests are also not allowed on campus unless it's to pick students up for the break.

Cornell is not the only college campus to be making changes due to a rise in COVID cases. Today, New York University announced that it is canceling all "nonessential" gatherings and events, including graduations, due to increasing case rates. And yesterday, Princeton University moved its finals online after it also experienced a rise in cases, which were believed to include cases of the Omicron variant. Of course, the variant isn't limited to college campuses; it has quickly spread across the country and has now been detected in the majority of states, per data from the Centers for Disease Control and Prevention (CDC). The World Health Organization (WHO) named Omicron a "variant of concern" on November 26, noting that it "has a large number of mutations, some of which are concerning."

All of this raises a lot of questions, including how a COVID-19 outbreak can happen in such a highly vaccinated population. Infectious disease experts break it down.

Outbreaks Among Fully Vaccinated People

First, it's important to quickly go over the data that we have so far on the COVID-19 vaccines. Here's a breakdown of the efficacy of these vaccines in preventing COVID-19 in clinical trials:

• Pfizer-BioNTech: 95%
• Moderna: 94.1%
• Johnson & Johnson: 66.3%

Those vaccines were largely tested before even the Delta variant was the dominant variant in the US, which likely makes their real-world numbers a little lower, William Schaffner, MD, an infectious disease specialist and professor at Nashville's Vanderbilt University School of Medicine, tells Health.

"The COVID-19 vaccines are good, but they're not perfect," Dr. Schaffner says. Infectious disease expert Amesh A. Adalja, MD, a senior scholar at Baltimore's Johns Hopkins Center for Health Security, agrees. "Vaccines are not magic force fields," he tells Health.

However, the vaccines are good at keeping people out of the hospital, according to Dr. Adalja. "The goal of vaccines is not to prevent every infection but to prevent serious infection," he says.

The rise of the Omicron variant is also complicating things slightly. So far, data have suggested that the variant may be able to only partially evade the COVID-19 vaccine. The Omicron variant "is expected to cause breakthroughs at a higher rate," Dr. Adalja says. Knowing that Omicron "significantly reduced" the ability of its two-shot regimen to neutralize the virus, Pfizer recently urged people to get a booster dose to up their protection.

There is a huge caveat with all of this, though: Cornell is testing its students regularly "and, because of that, they're able to pick up many asymptomatic and mildly symptomatic infections," Dr. Schaffner says. Meaning, while some of these fully vaccinated students are getting infected, they may not have even known they had COVID-19 without being tested.

What Does This Mean for the COVID-19 Vaccines?

Experts stress that vaccines are still crucial to fight the pandemic and keeping yourself safe. "These people probably wouldn't be tested in a normal population," Dr. Schaffner says. "The vaccine seems to keep the symptoms very mild if someone experiences them at all."

COVID-19 vaccines, he says, "are still very effective at keeping people out of the hospital. We need to keep coming back to that."

Risk of Future Outbreaks

Omicron is continuing to spread across the country, and experts say it has the potential to overtake the dominant Delta variant. "Its doubling rate is astonishing and may very well overtake Delta before the year is out," Dr. Schaffner says.

With that, more outbreaks like this are expected. "As Omicron becomes the dominant variant, breakthrough infections are going to be more common," Dr. Adalja says. "But we should focus less on breakthrough infections and really focus on hospitalizations."

Protecting Yourself

Doctors say there are a few things you can do to lower the risk you'll get sick:

• Get vaccinated against COVID-19.
• Get your booster shot when you're eligible.
• Wear a mask indoors when you're in public.
• Be mindful of your individual risk, and make decisions based on that.

"If you are in a high-risk group, think twice about attending indoor group activities," Dr. Schaffner says. And as the holidays approach, he recommends doing rapid testing the morning of family gatherings, just to be safe.