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Open Access Publications from the University of California

SARS-CoV-2 seroprevalence and neutralizing activity in donor and patient blood.

  • Author(s): Ng, Dianna L
  • Goldgof, Gregory M
  • Shy, Brian R
  • Levine, Andrew G
  • Balcerek, Joanna
  • Bapat, Sagar P
  • Prostko, John
  • Rodgers, Mary
  • Coller, Kelly
  • Pearce, Sandra
  • Franz, Sergej
  • Du, Li
  • Stone, Mars
  • Pillai, Satish K
  • Sotomayor-Gonzalez, Alicia
  • Servellita, Venice
  • Martin, Claudia Sanchez San
  • Granados, Andrea
  • Glasner, Dustin R
  • Han, Lucy M
  • Truong, Kent
  • Akagi, Naomi
  • Nguyen, David N
  • Neumann, Neil M
  • Qazi, Daniel
  • Hsu, Elaine
  • Gu, Wei
  • Santos, Yale A
  • Custer, Brian
  • Green, Valerie
  • Williamson, Phillip
  • Hills, Nancy K
  • Lu, Chuanyi M
  • Whitman, Jeffrey D
  • Stramer, Susan L
  • Wang, Candace
  • Reyes, Kevin
  • Hakim, Jill MC
  • Sujishi, Kirk
  • Alazzeh, Fariba
  • Pham, Lori
  • Thornborrow, Edward
  • Oon, Ching-Ying
  • Miller, Steve
  • Kurtz, Theodore
  • Simmons, Graham
  • Hackett, John
  • Busch, Michael P
  • Chiu, Charles Y
  • et al.

Given the limited availability of serological testing to date, the seroprevalence of SARS-CoV-2-specific antibodies in different populations has remained unclear. Here, we report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seroreactivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors in early April 2020. We additionally describe the longitudinal dynamics of immunoglobulin-G (IgG), immunoglobulin-M (IgM), and in vitro neutralizing antibody titers in COVID-19 patients. The median time to seroconversion ranged from 10.3-11.0 days for these 3 assays. Neutralizing antibodies rose in tandem with immunoglobulin titers following symptom onset, and positive percent agreement between detection of IgG and neutralizing titers was >93%. These findings emphasize the importance of using highly accurate tests for surveillance studies in low-prevalence populations, and provide evidence that seroreactivity using SARS-CoV-2 anti-nucleocapsid protein IgG and anti-spike IgM assays are generally predictive of in vitro neutralizing capacity.

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