Pregnancy and lactation induce distinct immune responses to COVID-19 booster vaccination and SARS-CoV-2 breakthrough infection

The widespread uptake of COVID-19 vaccines by women provided a unique opportunity to study the effects of pregnancy and lactation on immune responses to vaccination. Leveraging a cohort with well-defined SARS-CoV-2 exposure history, we found that the magnitude of humoral and cellular immune responses to vaccine-delivered SARS-CoV-2 spike was not affected by pregnancy or lactation status. However, vaccination during pregnancy elicited more stem-like SARS-CoV-2-specific CD4+ T cells. Moreover, breakthrough infection promoted spike-specific IgG in pregnant individuals in contrast to IgA in those lactating, suggesting that the pregnancy-to-lactation transition favors mucosal antibody responses. Breakthrough infection also reduced peripheral cytolytic SARS-CoV-2-specific CD8+ T cell frequencies during lactation but not pregnancy, which may reflect trafficking of the cells to mammary glands. Our study also uncovered an impact of pregnancy and lactation on global T cell phenotypes. In particul..., , , # Pregnancy and lactation induce distinct immune responses to COVID-19 booster vaccination and SARS-CoV-2 breakthrough infection

**Contact**:
Nadia Roan, PhD
Gladstone Institutes
University of California, San Francisco
[[e-mail]](mailto:[e-mail])
[[e-mail]](mailto:[e-mail])

**Dates of collection:** December 2020 to February 2022

**Information about the geographic location of data collection:** San Francisco Bay Area

**Key words:** SARS-CoV-2, CyTOF, T cells, pregnant, lactating

**Data and file overview:**

Included are 348 FCS files from 174 different CyTOF specimens. Each file name begins with a de-identified study participant identifier (ID). The Group category corresponds to whether the participant was non pregnant (Nonpreg), pregnant, or lactating at the time of specimen collection. The Status category indicates whether the sample was obtained prior (Pre) or subsequent (Post) to receiving a 3rd dose of a COVID-19 m..., This study was approved by the institutional review board of University of California, San Francisco (UCSF, IRB #20-32077 and IRB #19-29713) and written informed consent was obtained from all study participants, to publish de-identified data in the public domain.