We analyzed laboratory and exposure data from symptomatic students who sought care at the university’s health clinic during January 1–May 31, 2022. SHS staff collected nasal or nasopharyngeal swab samples from students and tested those specimens by using BioFire RSP 2.1 multiplex PCR (bioMérieux, https://www.biomerieux.com). We defined positive cases as students who manifested respiratory or constitutional symptoms and were HadV-positive in the multipathogen PCR panel.

SHS routinely collected demographic information, symptoms, and medical history from students seeking care at the university clinic. Those data were supplemented from March 22–May 10, 2022, by using focused call-back interviews of students who had confirmed HadV infections to identify potential transmission events and locations. We used the aggregate interview data to examine student behaviors and activities that might have been associated with transmission events.

We considered students who tested positive for HadV plus another respiratory pathogen on the multipathogen panel to have pathogen co-detections. We compared demographic characteristics, symptoms, and illness severity between students who had co-detections and those who were only infected with HadV by using t-tests.

During January 1–May 31, 2022, a total of 687 students were tested by using the respiratory multipathogen PCR panel after seeking care at SHS for acute respiratory or systemic symptoms. Of those 687 students, 195 (28.4%) tested positive for HadV; HadV infections were distributed evenly between men and women. The median age of infected students was 19 years (range 18–24 years) (Table 1). The most common symptoms reported by students were sore throat (85%), cough (76%), fever (75%), and headache (62%). Nausea and vomiting were reported by 27% of students; conjunctivitis was reported by 10% of students. No known emergency department visits, hospitalizations, or deaths were reported among any HadV-infected students. HadV-4 was identified in 30 swab specimens by partial genomic sequencing of the hexon gene (Appendix). We randomly selected 8 of those 30 sequences for whole-genome sequencing and performed phylogenetic analyses (Appendix Figure).

Figure

Figure. Number of adenovirus (A) and COVID-19 (B) cases at a university campus in South Carolina in study identifying a large adenovirus infection outbreak by multipathogen testing, South Carolina, USA, January...

Weekly case counts increased slowly during January–February and more rapidly after the week of March 6 (university spring break) (Figure). Rapid and detailed attention to surface decontamination in academic and residential buildings on campus was reported in February and early March. Mandatory masking recommendations as part of COVID-19 mitigation efforts were lifted in March. Cases fell precipitously after students left campus for summer break (week of May 1); no cases were reported after May 10, 2022. The outbreak investigation was closed on June 7 after 2 full incubation periods (total of 28 days).

Of all HadV-infected students, infections occurred most in first-year (39%) and second-year (30%) students. Most (115 [59%]) students lived in on-campus dormitories. Three of 22 affected dormitories had >10 students with confirmed HadV infections during the outbreak. We did not observe a preponderance of one academic area of study that might suggest clustering according to academic departments.

Among the 195 students who tested positive for HadV, >1 other respiratory pathogen was also detected in 43 (22%) students (Table 2). The most common co-detected viruses were human rhinovirus/enterovirus (28 [65%]), seasonal coronaviruses (9 [21%]), and SARS-CoV-2 (8 [19%]). Most (42 [98%]) HadV-infected students who had co-detected viruses reported a sore throat, compared with 124 (82%) students infected with only HadV (p = 0.001). More HadV-only–infected students (13%) reported conjunctivitis than students who had co-detected viruses (2%; p = 0.001). We did not observe a substantial difference in disease severity (i.e., need for intravenous fluids) among HadV-only–infected students compared with those who had virus co-detections (4% vs. 2%; p = 0.07).

The university clinic staff began interviewing students with confirmed HadV infection on March 21. Interviews were completed for 96 of 121 students with HadV (79% response rate) before the end of the outbreak. Most (62 [65%]) students did not know where they had acquired infection; 9 (9%) students had a known exposure to someone with confirmed HadV infection, and 18 (19%) students had exposure to someone with similar symptoms before illness onset. Seventy-five (78%) students had not traveled away from campus before their symptoms began. We were unable to link infections to campus or off-campus locations because of limited sample size.

This outbreak of respiratory illness attributed to HadV-4 was among the largest described HadV outbreaks on a university campus (9,12); symptoms and transmission were similar to other large HadV outbreaks in congregate settings (13). Infected students were mostly freshmen and sophomores living in dormitories, highlighting increased transmission in close university settings. The outbreak occurred during the COVID-19 pandemic, and detection of HadV might have been delayed without availability of multipathogen testing. The outbreak on campus appeared to end when student density decreased during summer break, and further transmission was not observed among the limited number of students remaining on campus.

SHS was able to detect and respond quickly to a potentially serious virus infection outbreak by using multipathogen testing. Furthermore, this testing enabled identification of students who were infected with multiple pathogens. In addition to SARS-CoV-2, many other respiratory viruses can be detected in university students, including those that cause illness and outbreaks. As universities move beyond COVID-19 as the main public health priority affecting students and campuses, renewed attention to other pathogens is needed (14). Continued surveillance of circulating viruses in congregate communities remains critical for ongoing risk communication and prevention efforts.