{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T07:02:59Z","timestamp":1779951779356,"version":"3.53.1"},"reference-count":22,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T00:00:00Z","timestamp":1779926400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Clinical characteristics and humoral immune responses in pregnant women following natural SARS-CoV-2 Omicron infection remain unclear, particularly in those previously receiving inactivated vaccines, which may induce immune imprinting and affect cross-neutralization against emerging Omicron subvariants.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This cross-sectional investigation was conducted in Zhejiang Province between December 2022 and April 2023.\u00a0A total of 223 pregnant women with a gestational age of at least six weeks and 31 healthy non-pregnant women were recruited as research subjects and controls. Serum specimens were collected to determine anti-RBD IgG levels by ELISA, alongside pseudovirus neutralizing antibody titers against the prototype strain and Omicron BA.4\/5, XBB.1.5 subvariants. Relevant clinical information was gathered through questionnaires, and multivariate regression analysis was applied to identify influencing factors of immune response characteristics.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Acute COVID-19 symptom profiles were comparable between pregnant women and non-pregnant healthy women (P &amp;gt; 0.05). Among questionnaire respondents, pregnant individuals had markedly prolonged symptom recovery, with a notably higher proportion taking over one week to recover (73.0% vs. 23.1%, P\u00a0=\u00a00.045), and presented a significantly higher medical consultation rate (73.0% vs. 15.4%, P &amp;lt; 0.001). For immune response, neutralizing antibody levels against the Omicron BA.4\/5 showed no intergroup difference overall. By contrast, pregnant women exhibited significantly lower XBB.1.5 neutralizing antibody titers than controls, with geometric mean titers of 16.35 and 45.96 respectively (P &amp;lt; 0.05). Multivariate regression analysis indicated that SARS-CoV-2 infection during the Omicron epidemic was the major independent factor linked to elevated neutralizing antibody levels, while a BMI below 25.0 kg\/m\u00b2 was independently correlated with higher XBB.1.5 neutralizing antibody titers. Additionally, no significant differences in clinical manifestations or immune responses were found among women in different trimesters of pregnancy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>In vaccine-primed pregnant women with natural Omicron infection, acute clinical manifestations and homologous humoral immunity against BA.4\/5 were similar to non-pregnant controls, but symptom recovery was prolonged and cross-neutralization against XBB.1.5 was reduced. No trimester-specific differences were observed.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1845051","type":"journal-article","created":{"date-parts":[[2026,5,28]],"date-time":"2026-05-28T06:19:34Z","timestamp":1779949174000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical characteristics and antibody responses to Omicron variants among pregnant women in China during the December 2022\u2013April 2023 COVID-19 pandemic wave"],"prefix":"10.3389","volume":"17","author":[{"given":"Ruijing","family":"Bao","sequence":"first","affiliation":[{"name":"School of Life Sciences and Agriculture and Forestry, Qiqihar University","place":["Qiqihar, China"]},{"name":"Department of Prevention and Control of Infectious Disease, Zhejiang Provincial Center for Disease Control and Prevention","place":["Hangzhou, 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China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haichang","family":"Yin","sequence":"additional","affiliation":[{"name":"School of Life Sciences and Agriculture and Forestry, Qiqihar University","place":["Qiqihar, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hangjie","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Prevention and Control of Infectious Disease, Zhejiang Provincial Center for Disease Control and Prevention","place":["Hangzhou, China"]},{"name":"Zhejiang Key Lab of Vaccines, Department of Prevention and Control of Infectious Disease, Zhejiang Provincial Center for Disease Control and Prevention","place":["Hangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,28]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1097\/js9.0000000000000522","article-title":"The WHO announced COVID-19 is no longer a 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