Blood donations suggest COVID-19 was in US last December
A study in Clinical Infectious Diseases yesterday found that 1% of US blood donations late last year and in early 2020 contained SARS-CoV-2 antibodies, suggesting that the virus was present in the United States earlier than previously thought.
SARS-CoV-2, the virus that causes COVID-19, was first recognized in Wuhan, China, in December 2019, and the initial US case was identified on Jan 19.
Researchers conducted serologic testing of 7,389 blood samples collected via routine American Red Cross blood donations from Dec 13, 2019 to Jan 17, 2020 in nine states—California, Connecticut, Iowa, Massachusetts, Michigan, Oregon, Rhode Island, Washington, and Wisconsin.
Blood samples were tested for anti–SARS-CoV-2 antibodies against the full viral spike protein using enzyme linked immunosorbent assay (ELISA), microneutralization tests, and receptor binding domain (RBD) blocking activity assays.
Of the 7,389 samples, 1.1%—84 samples from residents in all nine states—showed virus-neutralizing activity, binding activity, or RBD-blocking activity, suggesting the presence of anti–SARS-CoV-2–reactive antibodies. The mean age of reactive donors was 52 years, with a higher percentage of reactive donations in men (2.6% vs 1.4% from Dec 13 to Dec 16, 2019; 1.1% vs 0.7% from Dec 30, 2019 to Jan 17, 2020).
The earliest reactive samples came from donations collected from Dec 13 to Dec 16, 2019, from residents of California, Oregon, and Washington.
"The presence of these serum antibodies indicate that isolated SARS-CoV-2 infections may have occurred in the western portion of the United States earlier than previously recognized or that a small portion of the population may have pre-existing antibodies that bind SARS-CoV-2," the authors concluded.
Nov 30 Clin Infect Dis study
Study finds irreversible damage in COVID-19 lung transplant patients
A report in Science Translational Medicine yesterday detailed irreversible lung damage in three patients with severe COVID-19 infection who received lung transplants, with lung injury similar to that of end-stage pulmonary fibrosis. The study suggests that some COVID-19 patients develop fibrotic lung disease and that lung transplants may be a viable option for survival.
Researchers examined the lungs removed from three bilateral lung transplant patients with non-resolving COVID-19–associated respiratory failure and two patients who had died from COVID-19–associated pneumonia.
All patients had SARS-CoV-2–associated pneumonia and required prolonged mechanical ventilation and extracorporeal membrane oxygenation (ECMO) support.
The researchers found no evidence of SARS-CoV-2 RNA in the transplant patient lung samples using single-molecule fluorescent in situ hybridization but did find extensive injury and fibrosis—thickening or scarring of the air exchange tissues of the lung—that resembled end-stage pulmonary fibrosis.
Lung samples from transplant patients showed cavities with dead tissue that contained bacterial pathogens, suggesting acute secondary infections. All lung samples showed regions of diffuse hemorrhage, or bleeding, in the air sacs where gas exchange occurs.
The researchers compared RNA sequences of COVID-19 patients' lung tissue with samples from pulmonary fibrosis patients, finding similarities that suggest common pathways of tissue damage and fibrosis.
Transplant patients were treated with anti-rejection medications and antibiotics for secondary bacterial infections and showed improvement 3 months after transplant, with oxygen saturations over 95% on room air and improved cognitive status and muscular strength. No transplant patients showed evidence of COVID-19 reinfection.
While not supporting the routine use of lung transplant, the authors recommend bilateral transplant for patients with severe COVID-19 with extended mechanical ventilation and unlikely lung recovery. "Our findings suggest that some patients with severe COVID-19 develop fibrotic lung disease for which lung transplantation is their only option for survival," the authors noted.
Nov 30 Sci Transl Med study
Two Korean studies suggest that children are unlikely to spread COVID-19
Two South Korean studies in Emerging Infectious Diseases yesterday add to growing evidence that children are less likely than adults to spread COVID-19.
The first study examined SARS-CoV-2 transmission from Feb 18 to Jun 7 among 12 children (younger than 19 years) and their uninfected guardians isolated together in seven Korean hospitals.
Infected children were encouraged to wear face masks, but compliance was low—only four children were reported to have worn personal protective equipment (PPE) most of the time. Guardians—10 mothers, one father, and one uncle—all complied with PPE recommendations, wearing a variety of protective masks and gloves, but with most reporting frequent close contact with the isolated child. Isolation was lifted after two consecutive negative respiratory samples at least 24 hours apart were obtained from the infected child.
None of the guardians were SARS-CoV-2–positive during the study, and no transmission from children to guardians was observed during the isolation period or within the 2 weeks after the end of isolation.
"Appropriate use of PPE, especially face masks, might have protected uninfected guardians in our study," the authors suggested. "The study adds to growing evidence that young children are less likely to contribute to the spread of COVID-19 among their adult guardians."
The second study evaluated SARS-CoV-2 exposure and transmission at a childcare center attended by a 4-year-old presymptomatic child. The facility had complied with local health protocols, including mask wearing for all adult staff, frequent hand hygiene, and surface disinfection, but children wore masks inconsistently.
The infected child attended the 17-classroom center from Feb 19 to 21, developed a fever on Feb 22, and was diagnosed with SARS-CoV-2 infection on Feb 27. The childcare center was closed after the identification of a positive case, and an investigation identified 190 contacts—154 children and 36 adults—at the center, including 13 4- or 5-year-old classmates and two teachers in the child's classroom.
All 190 people were negative for SARS-CoV-2 when tested 8 or 9 days after exposure and, although two close contacts showed symptoms on the last day of quarantine, subsequent test results were negative.
"This investigation adds indirect evidence of low potential infectivity in a child care setting with exposure to a presymptomatic child," the study authors wrote.
Nov 30 Emerg Infect Dis hospital isolation study and child care study