tetano
Editor, Senior Moderator
PLoS One
. 2025 Oct 8;20(10):e0332645.
doi: 10.1371/journal.pone.0332645. eCollection 2025. Incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in North Carolina from December 2020 - February 2022
Elyse M Miller[SUP] 1 [/SUP], Ross M Boyce[SUP] 1 2 [/SUP], Aaron M Kipp[SUP] 3 [/SUP], L Kristin Newby[SUP] 4 5 6 [/SUP], Christopher W Woods[SUP] 7 8 9 [/SUP], Caitlin A Cassidy[SUP] 1 [/SUP], Annika K Gunderson[SUP] 1 [/SUP], C Suzanne Lea[SUP] 3 [/SUP], Coralei E Neighbors[SUP] 9 10 [/SUP], Bonnie E Shook-Sa[SUP] 11 [/SUP], Richard Sloane[SUP] 12 [/SUP], Anne P Starling[SUP] 1 [/SUP], David Wambui[SUP] 3 [/SUP], Douglas Wixted[SUP] 6 [/SUP], Aaron Fleischauer[SUP] 13 [/SUP], Allison E Aiello[SUP] 14 [/SUP]
Affiliations
Background: Surveillance estimates of SARS-CoV-2 infections over time have relied on mandatory clinician and laboratory reporting. These estimates increasingly underestimated true viral incidence due to asymptomatic infections, variable access to testing, and self-administered diagnostics. To overcome these limitations, the North Carolina Department of Health and Human Services partnered with academic researchers to conduct three concurrent population-based longitudinal cohort studies in three distinct North Carolina counties to offer more accurate estimates of the incidence, prevalence, and vaccination rates for SARS-CoV-2.
Methods: We enrolled and followed adult residents of three North Carolina counties from August 2020-February 2022. Demographic and health information was collected in biweekly surveys. Nasal swabs were collected biweekly and tested for SARS-CoV-2 using PCR testing. Blood samples were collected monthly and tested for antibodies to the SARS-CoV-2 nucleocapsid and spike proteins. We calculated monthly seroprevalence, sero-incidence, PCR test positivity, and vaccination uptake.
Results: We enrolled 646 participants. Routine blood samples and nasal swab samples were contributed by 639 and 642 participants, respectively. By February 2022, 98% (95% CI: 97.4-98.2) had antibodies to the SARS-CoV-2 spike protein, and 13% (95% CI: 12.4-14.2) had antibodies to the nucleocapsid protein, indicating viral exposure. PCR testing detected infection among 14% (95% CI: 13.1-15.0) of participants, but cumulative PCR test positivity was only 1.3% (95% CI: 1.2-1.4). Over half of PCR-detected infections were asymptomatic. By February 2022, 97% of participants had completed the primary vaccine series, and 52% had received a booster dose.
Conclusions: Nearly all participants had anti-SARS-CoV-2 antibodies by the end of follow-up, primarily through vaccination. The incidence of PCR-detected infections was similar to antibody testing, but PCR test positivity substantially underestimated incident infections. These findings emphasize the importance of prospective infection monitoring via antibody testing in a comprehensive approach to tracking viral infections in the community setting.
. 2025 Oct 8;20(10):e0332645.
doi: 10.1371/journal.pone.0332645. eCollection 2025. Incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in North Carolina from December 2020 - February 2022
Elyse M Miller[SUP] 1 [/SUP], Ross M Boyce[SUP] 1 2 [/SUP], Aaron M Kipp[SUP] 3 [/SUP], L Kristin Newby[SUP] 4 5 6 [/SUP], Christopher W Woods[SUP] 7 8 9 [/SUP], Caitlin A Cassidy[SUP] 1 [/SUP], Annika K Gunderson[SUP] 1 [/SUP], C Suzanne Lea[SUP] 3 [/SUP], Coralei E Neighbors[SUP] 9 10 [/SUP], Bonnie E Shook-Sa[SUP] 11 [/SUP], Richard Sloane[SUP] 12 [/SUP], Anne P Starling[SUP] 1 [/SUP], David Wambui[SUP] 3 [/SUP], Douglas Wixted[SUP] 6 [/SUP], Aaron Fleischauer[SUP] 13 [/SUP], Allison E Aiello[SUP] 14 [/SUP]
Affiliations
- PMID: 41060960
- PMCID: PMC12507194
- DOI: 10.1371/journal.pone.0332645
Background: Surveillance estimates of SARS-CoV-2 infections over time have relied on mandatory clinician and laboratory reporting. These estimates increasingly underestimated true viral incidence due to asymptomatic infections, variable access to testing, and self-administered diagnostics. To overcome these limitations, the North Carolina Department of Health and Human Services partnered with academic researchers to conduct three concurrent population-based longitudinal cohort studies in three distinct North Carolina counties to offer more accurate estimates of the incidence, prevalence, and vaccination rates for SARS-CoV-2.
Methods: We enrolled and followed adult residents of three North Carolina counties from August 2020-February 2022. Demographic and health information was collected in biweekly surveys. Nasal swabs were collected biweekly and tested for SARS-CoV-2 using PCR testing. Blood samples were collected monthly and tested for antibodies to the SARS-CoV-2 nucleocapsid and spike proteins. We calculated monthly seroprevalence, sero-incidence, PCR test positivity, and vaccination uptake.
Results: We enrolled 646 participants. Routine blood samples and nasal swab samples were contributed by 639 and 642 participants, respectively. By February 2022, 98% (95% CI: 97.4-98.2) had antibodies to the SARS-CoV-2 spike protein, and 13% (95% CI: 12.4-14.2) had antibodies to the nucleocapsid protein, indicating viral exposure. PCR testing detected infection among 14% (95% CI: 13.1-15.0) of participants, but cumulative PCR test positivity was only 1.3% (95% CI: 1.2-1.4). Over half of PCR-detected infections were asymptomatic. By February 2022, 97% of participants had completed the primary vaccine series, and 52% had received a booster dose.
Conclusions: Nearly all participants had anti-SARS-CoV-2 antibodies by the end of follow-up, primarily through vaccination. The incidence of PCR-detected infections was similar to antibody testing, but PCR test positivity substantially underestimated incident infections. These findings emphasize the importance of prospective infection monitoring via antibody testing in a comprehensive approach to tracking viral infections in the community setting.