Research Roundup: All About Covid

CIDRAP: Asymptomatic COVID-19 May Significantly Contribute To Transmission
Seventy-five percent of asymptomatic COVID-19 outpatients had mean to high RNA viral loads, and 50.6% of those whose samples were tested with culture assays had live cultures, according to a study today in Scientific Reports. The researchers say this indicates that COVID-19 asymptomatic adult outpatients could play a large role in perpetuating COVID outbreaks. The study was conducted before the much more transmissible Delta (B1617.2) variant was circulating. (10/18)

JAMA Network: Association Between Risk Of COVID-19 Infection In Nonimmune Individuals And COVID-19 Immunity In Their Family Members 
This nationwide cohort study showed that individuals without COVID-19 immunity had a 45% to 97% lower risk of infection that was in line with the increase in the number of immune family members. Similar results were found regardless of whether immunity was acquired from a previous infection, a single dose of vaccine, or full vaccination. These findings suggest that vaccines are associated with a reduction in the transmission of the SARS-CoV-2 virus within families, which likely has implications for herd immunity and pandemic control. However, caution is warranted given the emerging variants of concern, which appear more transmissible and may be less sensitive to a single dose of vaccine. (Nordstrom et al, 10/11)

CIDRAP: Obesity Linked To COVID-19 Death, Longer ICU Stay
High body mass index (BMI) was independently associated with death and longer intensive care unit (ICU) stays for hospitalized COVID-19 patients, according to a study published yesterday in PLOS One. The researchers looked at Sweden's nationwide ICU population from Mar 6 to Aug 30, 2020, and found 1,649 adults with COVID-19, of whom 78.3% were at least overweight (25 kilograms per square meter [kg/m2] or more). Besides having an overrepresentation of obese people compared with Sweden's general population (39% in the cohort), the study group also consisted of more men (74.4%). Mean age was 60.1 years. (10/14)

CIDRAP: Overweight, Obesity Linked To More, Longer Mild COVID-19 Symptoms
COVID-19 outpatients were more likely to have more respiratory symptoms if they were overweight or obese, according to a study published yesterday in Influenza and Other Respiratory Viruses. The researchers enrolled 522 people, 63.8% of whom were considered overweight or obese, from June 2020 to January 2021 within 2 weeks of a known household exposure to COVID-19. During a 28-day follow-up in which participants reported their symptoms and sought regular testing, 85.1% ended up positive for COVID-19 (261 adults, 61 adolescents 12 to 17 years old, and 148 children). (10/20)

CIDRAP: Hospital-Acquired COVID-19 Affects Patients, Workers, Study Says
While the absolute risk of acquiring COVID-19 in the hospital was low—up to 0.75% risk per day of exposure pre-Delta (B1617.2) variant—patients or healthcare workers (HCWs) with COVID-19 nonetheless can be factors in the spread of COVID-19, a study published yesterday in PLOS One says. The researchers looked at four UK teaching hospitals, where 66,184 patients were hospitalized and 5,569 HCWs were on the job from Jan 12 to Oct 2, 2020. Of the patients, 1.4% had a positive test within the same period, and 10.5% of those (97) had their first positive test post-hospitalization at least 7 days after admission, wherein they were considered a nosocomial case. Patients who likely acquired COVID-19 infections while in the hospital were older, had longer lengths of stay, and had more readmission, the researchers note. (10/13)

CIDRAP: Study: Home Monoclonal Antibody Program Averted COVID Hospital Care
A research letter today in JAMA Network Open describes how nurses in Michigan may have reduced emergency department visits and hospitalizations of high-risk COVID-19 patients by coordinating at-home administration of neutralizing monoclonal antibodies (MABs) during the spring 2021 surge. (Van Beusekom, 10/14)