Since Jan. 1, 2022, 26.4 percent of undergraduates have tested positive for COVID-19 under the University’s testing protocol, which includes both symptomatic and asymptomatic cases. The University reports that 31.8 percent of undergraduates have tested positive since the pandemic started.
5.5 percent of graduate students and 9.9 percent of faculty and staff have also received a positive test, creating a combined total of more than 15 percent of the campus community.
From August 2020 through 2021, faculty and staff positives represented a slight majority of cases. In 2022, undergraduates have led and continue to lead in COVID-19 cases at the University — despite the fact that they represent barely a third of the campus community.
The caseload for undergraduates — as reported by the University’s COVID-19 Dashboard — has reached staggering figures after multiple sharp outbreaks, while cases from other campus communities have increased at much slower rates. The chart below shows the percentage of each major campus group (undergraduates, faculty/staff, and graduate students) that has tested positive in 2022 over time. Figures for student populations were taken from the Common Data Set, while those for faculty and staff populations were taken from the Integrated Postsecondary Education Data System.
The Daily Princetonian’s analysis assumes that each positive test corresponds to a new person; however, it is possible to catch the virus multiple times, causing some data here to be underestimates.
Tests are only processed on weekdays. (This explains the sharp incline in the chart on weekdays, and the plateaus — when no tests are processed — on weekends.)
Since Feb. 14, undergraduate cases began to dominate COVID-19 case counts on campus. This phenomenon was especially surprising because of the relatively small number of undergraduates in the University community. If every member of the University community — every student, Ph.D. candidate, custodian, professor — gathered in a room, there would be more than 15,000 people, with undergraduates far outnumbered.
The test counts show a similar disproportion: faculty, staff, and graduate students together make up the majority of the people under the testing protocol.
In the chart below, we see the same time scale as above, but instead of showing the percentages of the three groups, we only see the number of cases in each group.
The rise in undergraduate cases on campus came toward the end of the omicron wave across the United States. While cases were steeply declining across the nation and more importantly, in New Jersey, each passing week saw a large uptick in undergraduate cases. This trend continued until after the sixth week of the spring semester — the week of spring break — when many students left the campus, exiting its testing protocol.
The raw case counts begin to show that although only about 35 percent of individuals in the testing protocol are undergraduate students, undergraduates are not outnumbered in one crucial area: positive tests.
Despite representing 35 percent of the campus community’s population and comprising 40 percent of the tests since Jan. 1, undergraduates represent 62 percent of the cases in the same period.
There are a few confounding factors: some students test more frequently due to their participation in sports and performing groups, for instance, but those who test positive are removed from the testing protocol, decreasing the number of tests. Even accounting for these blurring factors, compared to population and tests, undergraduates have a disproportionately larger caseload.
Last semester, and since the start of the pandemic, case counts have been spread more evenly between the three groups. Below is the same chart as above, but for the full pandemic up to the end of 2021. Note that the asymptomatic testing protocol began in August 2020 when students first returned to campus.
Faculty, who represent 46 percent of the population, represented 52 percent of the cases, while undergraduates, who represented 34 percent of the population, represented 33 percent of the cases. This falls in sharp contrast to the trends of the current spring semester and shows the scale of the recent outbreak among the undergraduates.
This increase — from undergraduates representing 33 percent of cases in December 2021 to 62 percent of cases in March 2022 — happened quickly. The following chart tracks the proportions of year-to-date cases among the major campus groups over the course of 2022. The faculty portion, which used to be the vast majority of cases, shrinks as the undergraduate portion grows larger and larger through the multiple outbreaks in February.
Along with this increase in cases, the data shows an extreme increase in positivity rates across all groups. This chart shows all-time positivity rates — a figure calculated as total positive cases, divided by total tests, over a period of time.
Positivity rates were low among all groups in 2020 and 2021: fewer than 0.1 percent of 220,454 undergraduate tests came back positive. That figure was twice as high — up to about 0.2 percent of 226,336 tests — for faculty and staff.
Since Jan. 1, 1.5 percent of the 46,067 tests faculty and staff have submitted this year have come back positive. But now, the undergraduate figure is twice as high as that of the faculty and staff, with more than a 3 percent positivity rate out of their 46,820 tests. Far fewer tests along with far more cases means an extremely high positivity rate. Note that this is a shorter period, and students were only required to submit one test a week for most of it. This increased positivity rate correlates with the precipitous increase in cases among the undergraduates seen above.
In the past few weeks, caseloads have declined as the University lifted its mask mandate and altered its testing protocol; students now only test once a month instead of once a week. With the community taking far fewer tests, COVID-19 data will be difficult to compile in any sense on campus: Students may catch COVID-19 and pass through the course of infection, all while never taking a test. Thus, the figures reported in this article may be an underestimate, due to the change in testing protocol in the last two weeks.
Still, the caseload continues to climb, and daily positive tests are still dominated by undergraduates, as they have been nearly every single day since the start of the semester. In 2022, the undergraduate student body defines the pandemic at Princeton.
Gabriel Robare is a staff writer, as well as a Head Puzzles Editor, for the ‘Prince.’ He can be reached at firstname.lastname@example.org or on social @gabrielrobare.