TY - JOUR
T1 - COVID-19 serological survey utilizing antenatal serum samples in British Columbia
AU - Márquez, Ana Citlali
AU - Beitari, Saina
AU - Valadbeigy, Tahereh
AU - Sbihi, Hind
AU - Zlosnik, James
AU - Forward, Lucia
AU - Mansour, Sarah
AU - Nesbitt, Zoey
AU - Tanunliong, Guadalein
AU - Krajden, Mel
AU - Jassem, Agatha
AU - Sekirov, Inna
AU - Money, Deborah
AU - Antenatal Serostudies Team
AU - Atkinson, Andrea
AU - Albert, Arianne
AU - McClymont, Elisabeth
AU - Andrade, Janice
AU - Beach, Lori
AU - Bolotin, Shelly
AU - Boucoiran, Isabelle
AU - Bullard, Jared
AU - Charlton, Carmen
AU - Crane, Joan
AU - Dougan, Shelley
AU - Forest, Jean-Claude
AU - German, Greg J.
AU - Giguère, Yves
AU - Girouard, Gabriel
AU - Hankins, Catherine
AU - Krajden, Mel
AU - Lang, Amanda
AU - Levett, Paul
AU - Minion, Jessica
AU - Neudorf, Cory
AU - Poliquin, Vanessa
AU - Robinson, Jason L.
AU - Scott, Heather
AU - Stein, Derek R.
AU - Tran, Vanessa
AU - Zahariadis, George
AU - Zhou, Hong Y.
N1 - Publisher Copyright:
© 2024
PY - 2025/8/13
Y1 - 2025/8/13
N2 - The COVID-19 pandemic, caused by SARS-CoV-2, highlighted the need for accurate and timely data on virus spread and immune responses at a population level. Serological surveys offer a comprehensive view of population-level immune response to SARS-CoV-2 post- infection and/or vaccination. Here, we performed a serial cross-sectional study from residual serum samples collected from pregnant individuals in British Columbia during their first trimester antenatal screening. A total of 28,050 samples were collected between November 2021 and March 2024. We tracked changes in antibody levels over time and examined differences in antibody responses based on age and vaccination status during different phases of the pandemic. Antenatal serum samples enabled tracking of SARS-CoV-2 serostatus within the population and waves of major SARS-CoV-2 infections, such as the Omicron surge in 2021–2022 and increases in infection during the 2023–2024 respiratory season. During the 2023–2024 season, we observed a significant rise in Nucleocapsid (N) seropositivity compared to the previous year, reaching 64.3 % in the vaccinated group and 67.05 % in the unvaccinated group. This suggests a high infection rate, likely driven by the latest Omicron variants. Additionally, we differentiated between infection-induced and vaccine-induced seroprevalence. By March 2024, Spike (S) seroprevalence was 94 % in the unvaccinated group and 100 % in the vaccinated group. We assessed the longevity of vaccine-induced antibody within the population. A significant negative correlation was observed between S seropositivity (indicative of vaccination without infection, S+/N-) and time since the last vaccine dose. In contrast, anti-N levels began to rise above the cut-off value of seropositivity 15 months post-vaccination, indicating increased infection rates and N seroprevalence as time post-vaccination increased. This serosurveillance approach provide critical insights for public health strategies for the future, emphasizing the importance of ongoing serosurveillance to help understand corelates of seroprotection at a population level and to support ongoing evidence-based vaccine policy.
AB - The COVID-19 pandemic, caused by SARS-CoV-2, highlighted the need for accurate and timely data on virus spread and immune responses at a population level. Serological surveys offer a comprehensive view of population-level immune response to SARS-CoV-2 post- infection and/or vaccination. Here, we performed a serial cross-sectional study from residual serum samples collected from pregnant individuals in British Columbia during their first trimester antenatal screening. A total of 28,050 samples were collected between November 2021 and March 2024. We tracked changes in antibody levels over time and examined differences in antibody responses based on age and vaccination status during different phases of the pandemic. Antenatal serum samples enabled tracking of SARS-CoV-2 serostatus within the population and waves of major SARS-CoV-2 infections, such as the Omicron surge in 2021–2022 and increases in infection during the 2023–2024 respiratory season. During the 2023–2024 season, we observed a significant rise in Nucleocapsid (N) seropositivity compared to the previous year, reaching 64.3 % in the vaccinated group and 67.05 % in the unvaccinated group. This suggests a high infection rate, likely driven by the latest Omicron variants. Additionally, we differentiated between infection-induced and vaccine-induced seroprevalence. By March 2024, Spike (S) seroprevalence was 94 % in the unvaccinated group and 100 % in the vaccinated group. We assessed the longevity of vaccine-induced antibody within the population. A significant negative correlation was observed between S seropositivity (indicative of vaccination without infection, S+/N-) and time since the last vaccine dose. In contrast, anti-N levels began to rise above the cut-off value of seropositivity 15 months post-vaccination, indicating increased infection rates and N seroprevalence as time post-vaccination increased. This serosurveillance approach provide critical insights for public health strategies for the future, emphasizing the importance of ongoing serosurveillance to help understand corelates of seroprotection at a population level and to support ongoing evidence-based vaccine policy.
KW - Antenatal samples
KW - COVID-19 boosters
KW - Multiplex serology
KW - Serology surveillance
KW - Vaccines
UR - https://www.scopus.com/pages/publications/105007032166
U2 - 10.1016/j.vaccine.2025.127310
DO - 10.1016/j.vaccine.2025.127310
M3 - Article
C2 - 40472672
SN - 0264-410X
VL - 61
JO - Vaccine
JF - Vaccine
M1 - 127310
ER -
