SARS-CoV-2 seroprevalence among parturient women in Philadelphia

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Science Immunology  29 Jul 2020:
Vol. 5, Issue 49, eabd5709
DOI: 10.1126/sciimmunol.abd5709

Monitoring SARS-CoV-2 exposure

When the SARS-CoV-2 pandemic started, stay-at-home orders led to postponement of routine medical appointments, making it difficult to perform community-level seroprevalence studies. Pregnant women, particularly those near their delivery dates, continued to have regular interactions with their medical care providers. Flannery et al. measured the exposure rate of SARS-CoV-2 in parturient women in Philadelphia who came to the hospital to deliver between 4 April and 3 June 2020. Using IgG and IgM antibody tests, they evaluated exposure of 1293 parturient women to SARS-CoV-2 and found that 6.2% of these women had evidence of exposure to the virus. They found considerable racial differences in exposure rates, with higher rates of seropositivity in Black/non-Hispanic and Hispanic/Latino women as compared with Asian and White/non-Hispanic women.


Limited data are available for pregnant women affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Serological tests are critically important for determining SARS-CoV-2 exposures within both individuals and populations. We validated a SARS-CoV-2 spike receptor binding domain serological test using 834 pre-pandemic samples and 31 samples from COVID-19–recovered donors. We then completed SARS-CoV-2 serological testing of 1293 parturient women at two centers in Philadelphia from 4 April to 3 June 2020. We found 80 of 1293 (6.2%) of parturient women had immunoglobulin G (IgG) and/or IgM SARS-CoV-2–specific antibodies. We found race/ethnicity differences in seroprevalence rates, with higher rates in Black/non-Hispanic and Hispanic/Latino women. Of the 72 seropositive women who also received nasopharyngeal polymerase chain reaction testing during pregnancy, 46 (64%) were positive. Continued serologic surveillance among pregnant women may inform perinatal clinical practices and can potentially be used to estimate exposure to SARS-CoV-2 within the community.

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