Table 4.

Seroprevalence of SARS-CoV-2 antibodies among participants in the Safe Campus Initiative, June–August 2020

	Baseline, N (%)	Endline, N (%)	Both, N (%)
Serostatus—cross-sectional*
Reactive	18 (0.6)	48 (2.3)	–
Non-reactive	2859 (99.4)	2039 (97.7)	–
Serostatus—longitudinal†
Non-reactive → non-reactive	–	–	2029 (97.7)
Non-reactive → reactive	–	–	33 (1.6)
Reactive → non-reactive	–	–	0 (0)
Reactive → reactive	–	–	14 (0.7)
Serostatus—previous qPCR positive‡
Reactive	–	34 (82.9)	–
Non-reactive	–	7 (17.1)	–

*N=2888 participants who provided at least one blood sample.

†N=2076 participants who provided blood samples at baseline and endline.

‡N=41 participants who provided an endline blood sample ≥7 days after SARS-CoV-2 infection identified via positive qPCR test.

qPCR, quantitative PCR.