COVID-19: Risk During Prenatal Visits / Household & Other Transmission / Diabetes & Mortality / Rapid Saliva Test

By Amy Orciari Herman

Edited by Susan Sadoughi, MD, and André Sofair, MD, MPH

Take a look at some of latest developments in COVID-19:

Risk during prenatal visits: New research published in JAMA may offer reassurance to women seeking prenatal care during the pandemic. Researchers in Boston matched roughly 90 pregnant women who tested positive for SARS-CoV-2 and delivered between mid-April and late June with 370 pregnant controls who did not contract the virus (all were tested for SARS-CoV-2 at admission for delivery). The average number of in-person prenatal visits after early March did not differ between the cases and controls (3 visits). The researchers say the findings "suggest in-person health care visits were not likely to be an important risk factor for infection and that necessary, in-person care can be safely performed."

Household & other transmission: Household exposure to SARS-CoV-2 confers the greatest risk for transmission, while exposure on public transportation seems to confer the least, a study in the Annals of Internal Medicine suggests. Researchers studied roughly 3400 close contacts of nearly 400 COVID-19 patients in Guangzhou, China. In addition to traditional contact tracing, public health officials used mobility data from cell phones to identify exposure on public transportation. Overall, nearly 4% of all contacts became infected. Some 10% of household contacts were infected versus 1% of those exposed in healthcare settings and 0.1% of those exposed on public transportation. The risk for transmission increased as the severity of the index case increased, from 0.3% with an asymptomatic index case to 13.6% with an expectorating symptomatic case.

Diabetes & COVID-19 mortality: Both type 1 and type 2 diabetes are independent predictors of COVID-19 mortality, according to a study in The Lancet Diabetes and Endocrinology. Between March and May, the unadjusted rate of in-hospital death with COVID-19 among U.K. patients was 138 per 100,000 for those with type 1 diabetes and 260 per 100,000 with type 2 diabetes — compared with 27 per 100,000 for nondiabetics. After adjustment for age, cardiovascular comorbidities, and other confounders, the odds ratio for COVID-19 mortality was 2.9 for type 1 diabetes and 1.8 for type 2 diabetes.

Rapid saliva test: The FDA has issued an emergency use authorization for a rapid saliva test for SARS-CoV-2 developed at the Yale School of Public Health. While it's the fifth saliva test to be authorized, the SalivaDirect test is "unique because it does not require a separate nucleic acid extraction step," the agency noted in a news release. Nucleic acid extraction kits required with other tests have often been in short supply, which put a limit on testing. In addition, SalivaDirect is compatible with a range of common reagents and instruments, so it can be used widely in "most high-complexity labs," the FDA said. (Editor's note: Dr. André Sofair, deputy editor of Physician's First Watch, is a professor of medicine, epidemiology, and public health at Yale but had no role in the development of this test.)

CDC clarification: The CDC on Friday clarified a recent statement that a person can test positive for SARS-CoV-2 for up to 3 months after diagnosis without posing a risk to others. The agency said, "This science does not imply a person is immune to reinfection with SARS-CoV-2 ... in the 3 months following infection."