We at SGUL propose a rapid national study which aligns closely with the WHO MNCAH generic protocol, to inform public health policy within a 12 month timeframe by collecting samples from pregnant women during pregnancy and at delivery and from their infants to assess exposure and immunity to SARS-CoV-2.
We are already linked with existing UK surveillance studies (UKOSS, PAN COVID, BPSU) to ensure a joined up approach to data collection. Our study also leverages an existing framework, iGBS3, set up to understand the seroepidemiology of Group B Streptococcal disease in 320,000 pregnant women in the UK. Knowledge of protective immunity will also be of critical value in considering the role for COVID-19 vaccines in pregnant women.
Approximately 650,000 women deliver annually in the UK, and approximately 7% of pregnant women have been exposed to SARS-COV-2. These data represent women with severe disease requiring hospitalisation, so may not represent the full impact of SARS-CoV-2 on pregnancy and infant outcomes, as many may be asymptomatic(16,17,18). Studying women for SARS-CoV-2 antibodies and viral DNA regardless of symptomatology is required to estimate the true burden among mothers and babies and to determine the extent of mother-to-child transmission.
Placental transfer of IgG during pregnancy provides passive immunity that is critical in protecting newborns against infections. Maternal immunization can boost protective IgG, reducing neonatal morbidity, as seen with tetanus  and influenza [22,23]. A number of COVID-19 vaccines are now in clinical development, which may be suitable for pregnant women. We must now gather data on natural immunity to SARS-CoV-2 in pregnant women, including seroprevalence, placental transfer and the duration of antibody persistence in infants to understand the role for maternal vaccination, ensure equitable inclusion of pregnant women into trials of candidate vaccines and, ultimately, to provide effective and safe COVID-19 vaccines .
Many maternity units are now routinely swabbing pregnant women, presenting a unique opportunity to understand the seroepidemiology of SARS-CoV-2 in pregnancy and the peripartum and to prospectively monitor vertical transmission. By collecting samples from a large cohort of pregnant women, and from the newborns of women who had COVID-19 infection during pregnancy (irrespective of symptoms), we hope to understand the seroepidemiology of SARS-COV-2 and the risk and mode of perinatal transmission of the novel coronavirus. This study will provide a robust evidence base to inform guidance and policy decisions for the clinical and public health management of pregnant women, their infants and the staff that care for them.
Determine the seroepidemiology of SARS-CoV-2 in pregnant women and infants in England
Determine the placental transfer ratio of antibodies specific to SARS-CoV-2
Determine the concentration of SARS-CoV-2 antibodies in breastmilk of mothers who have tested rtPCR positive at any point during pregnancy
Determine the rate of mother to child transmission of SARS-CoV-2 in women who have tested rtPCR positive at any point during pregnancy
Determine the quantity (of both DNA and live virus) of SARS-COV-2 in maternal bodily fluids, including breastmilk, and in the placenta, in women who have tested positive for SARS-COV-2 by rtPCR at any point during pregnancy