Main Findings
In this large sample of patients admitted for labor and delivery undergoing universal SARS-CoV-2 testing during the height of the initial surge of infections in Massachusetts, we observed an overall 2.8% risk of infection, with three-quarters of infected patients being asymptomatic. The risk was largely clustered in patients with distinct demographic and occupational characteristics.
The risk of infection was 12% for women living in the towns most heavily affected by COVID-19 based on publicly reported case rates in the general population, compared to 0.5% for those living in towns with the lowest infection rates. Approximately 14% of Hispanic women and 5% of African American women were infected, versus 0.8% of Caucasian and Asian women. The risk of infection in public health beneficiaries was more than ten-fold higher than in privately insured women. Essential workers outside of healthcare had a markedly high risk of infection, 14%. Furthermore, 93.5% of patients with SARS-CoV-2 infection had at least one of six factors associated with infection; over half had four or more.
The factors associated with SARS-CoV2 infection may vary between communities and are likely to evolve as the pandemic progresses in various settings. Based on Massachusetts data at the peak of the spring 2020 surge, the strong association of infection with particular demographic characteristics and neighborhoods suggest the need for public health officials and clinicians to track and use this type of data as outbreaks occur in order to implement interventions aimed at decreasing infection rates in particular communities.18 The high risk of infection in non-healthcare essential workers suggests that directive work-related precautions should be offered to women who work in non-healthcare related high risk settings, if at all possible. As having a household member with known SARS-CoV-2 infection was also strongly associated with infection at the time of admission for labor and delivery, all household members should be counseled to take precautions to avoid infection, which may prevent transmission of the virus to the parturient. Risk stratification of patients at risk for SARS-CoV-2 infection is also instructive at the hospital level. Some hospitals may not have the capacity to test all parturients or may not have rapid SARS-CoV-2 testing available, leading to a need to prioritize patients at highest risk for infection for testing.
Our data demonstrate that pregnant women from vulnerable populations were disproportionately affected by SARS-CoV2 infection during the first wave of infection in Massachusetts. These trends are in line with the widespread racial and socioeconomic disparities in COVID-19 seen in the general population in several geographic areas, and though explanations for these disparities are multifold, it is likely that residence in crowded urban settings, poverty and employment in essential occupations, and decreased access to care play a role.19,20 Thus, there are profound racial and economic disparities in COVID-19 in pregnant women in Massachusetts that track racial and economic disparities in maternal health and obstetrical outcomes observed more generally.21
Compared to data from our study, the documented rates of new SARS-CoV-2 infection per capita in the state of Massachusetts for the people aged 20-39 was multi-fold lower,1 likely due to a substantial undercounting of disease burden given widespread asymptomatic disease and limited testing available for the general population. Most SARS-CoV-2 testing is performed due to patient symptoms; there are few settings where ongoing universal screening of otherwise healthy patients is conducted. Thus, such universal testing can provide valuable insight into the disease dynamics in the community and can be used to monitor the burden of disease.3-6