SARS-CoV-2 circulation in pregnant women from central Argentina: mortality rate, infecting variants and a positive impact of the vaccine

Introduction: SARS-CoV-2 can lead to a more severe infection during pregnancy. However, population-level data on COVID-19 disease and vaccine uptake in this population group are lacking, especially in South America.

Objective: We aimed to describe SARS-CoV-2 infection in pregnant women from a central region of Argentina.

Methodology: From March-2020 to March-2022, 2407 cases of pregnant women from Córdoba province with confirmed SARS-CoV-2 infection reported in the official records were analyzed. The infectivity and mortality rates were calculated; a control group of non-pregnant women infected with SARS-CoV-2 was included. Sixty-six samples were subjected to variants of concern (VOC) detection by real time RT-PCR.

Results: The overall infection rate was 0.25%, and the number of infections mirrored the number of cases for general population. In September-2021 (when mass vaccination in pregnant women occurred) the infection rate decreased (0.35% in March 2020-September 2021 vs. 0.14% in October 2021-March 2022). The global fatality rate was 0.75% (18/2407). During March-2020 to September-2021 the fatality rate was higher than in the control group: 1.01% vs. 0.08% (p<0.05). Since then, no deaths were recorded in pregnant women (fatality rate 0% vs. 0.01% in the control group). The VOCs distribution was: Gamma: 56%, Delta: 20%, Omicron: 12%, Alpha: 3%, 9% of non-VOC lineages.

Conclusions: The fatality rate found was similar to that obtained for the entire country in this group, and higher than the control group. The frequency of VOCs reflected what happened in the general population. The decrease in cases and deaths since September-2021 correlated with the mass vaccination in this group.