Post lockdown COVID-19 seroprevalence and circulation at the time of delivery, France

Mattern, Jeremie; Vauloup-Fellous, Christelle; Zakaria, Hoda; Benachi, Alexandra; Carrara, Julie; Letourneau, Alexandra; Bourgeois-Nicolaos, Nadege; Luca, Daniele De; Doucet-Populaire, Florence; Vivanti, Alexandre J.

Background To fight the COVID-19 pandemic, lockdown has been decreed in many countries worldwide. The impact of pregnancy as a severity risk factor is still debated, but strict lockdown measures have been recommended for pregnant women. Objectives To evaluate the impact of the COVID-19 pandemic and lockdown on the seroprevalence and circulation of SARS-CoV-2 in a maternity ward in an area that has been significantly affected by the virus. Study design Prospective study at the Antoine Beclere Hospital maternity ward (Paris area, France) from May 4 (one week before the end of lockdown) to May 31, 2020 (three weeks after the end of lockdown). All patients admitted to the delivery room during this period were offered a SARS-CoV-2 serology test as well concomitant SARS-CoV-2 RT-PCR on a nasopharyngeal sample. Results A total of 249 women were included. Seroprevalence of SARS-CoV-2 was 8%. The RT-PCR positive rate was 0.5%. 47.4% of the SARS-CoV-2-IgG-positive pregnant women never experienced any symptoms. A history of symptoms during the epidemic, such as fever, myalgia and anosmia, was suggestive of previous infection. Conclusions Three weeks after the end of lockdown, SARS-CoV-2 infections were scarce in our region. A high proportion of SARS-CoV-2-IgG-negative pregnant women must be taken into consideration in the event of a resurgence of the pandemic in order to adapt public health measures to reduce exposure to the virus, such as social distancing and teleworking for this specific population.