April 23, 2021

Clinical Reports

  • KFF/The Washington Post Frontline Health Care Workers Survey
    This partnership survey from the Kaiser Family Foundation (KFF) and The Washington Post examines the experiences and attitudes of frontline health care workers during the coronavirus pandemic. These individuals, who work across many different health care fields including doctors and nurses, nursing home managers, front desk clerks, as well as those who assist with patient care such as bathing, eating, cleaning, exercising, or housekeeping, have been on the front lines of an industry providing care for the sickest adults. The project includes interviews with a nationally representative sample of 1,327 frontline health care workers (those with direct contact with patients and their bodily fluids), representing hospitals, doctors’ offices, outpatient clinics, nursing homes and assisted care facilities, and those working in home health care. The sample includes workers who work in many, and multiple, aspects of patient care. The project also includes a comparison survey allowing researchers to compare the group of frontline health care workers to the general population, that included 971 U.S. adults not working as frontline health care workers.

  • SARS-CoV-2 seropositivity and subsequent infection risk in healthy young adults: a prospective cohort study
    Whether young adults who are infected with SARS-CoV-2 are at risk of subsequent infection is uncertain. Authors investigated the risk of subsequent SARS-CoV-2 infection among young adults seropositive for a previous infection. This analysis was performed as part of the prospective COVID-19 Health Action Response for Marines study (CHARM). CHARM included predominantly male US Marine recruits, aged 18–20 years, following a 2-week unsupervised quarantine at home. After the home quarantine period, upon arrival at a Marine-supervised 2-week quarantine facility (college campus or hotel), participants were enrolled and were assessed for baseline SARS-CoV-2 IgG seropositivity, defined as a dilution of 1:150 or more on receptor-binding domain and full-length spike protein ELISA. Participants also completed a questionnaire consisting of demographic information, risk factors, reporting of 14 specific COVID-19-related symptoms or any other unspecified symptom, and brief medical history. SARS-CoV-2 infection was assessed by PCR at weeks 0, 1, and 2 of quarantine and participants completed a follow-up questionnaire, which included questions about the same COVID-19-related symptoms since the last study visit. Participants were excluded at this stage if they had a positive PCR test during quarantine. Participants who had three negative swab PCR results during quarantine and a baseline serum serology test at the beginning of the supervised quarantine that identified them as seronegative or seropositive for SARS-CoV-2 then went on to basic training at Marine Corps Recruit Depot—Parris Island. Three PCR tests were done at weeks 2, 4, and 6 in both seropositive and seronegative groups, along with the follow-up symptom questionnaire and baseline neutralising antibody titres on all subsequently infected seropositive and selected seropositive uninfected participants (prospective study period). Seropositive young adults had about one-fifth the risk of subsequent infection compared with seronegative individuals. Although antibodies induced by initial infection are largely protective, they do not guarantee effective SARS-CoV-2 neutralisation activity or immunity against subsequent infection. These findings might be relevant for optimisation of mass vaccination strategies.

  • COVID-19 neuropathology at Columbia University Irving Medical Center/New York Presbyterian Hospital
    Many patients with SARS-CoV-2 infection develop neurological signs and symptoms, though, to date, little evidence exists that primary infection of the brain is a significant contributing factor. Authors present the clinical, neuropathological, and molecular findings of 41 consecutive patients with SARS-CoV-2 infections who died and underwent autopsy in our medical center. The mean age was 74 years (38–97 years), 27 patients (66%) were male and 34 (83%) were of Hispanic/Latinx ethnicity. Twenty-four patients (59%) were admitted to the intensive care unit (ICU). Hospital-associated complications were common, including 8 (20%) with deep vein thrombosis/pulmonary embolism (DVT/PE), 7 (17%) patients with acute kidney injury requiring dialysis, and 10 (24%) with positive blood cultures during admission. Eight (20%) patients died within 24 hours of hospital admission, while 11 (27%) died more than 4 weeks after hospital admission. Neuropathological examination of 20–30 areas from each brain revealed hypoxic/ischemic changes in all brains, both global and focal; large and small infarcts, many of which appeared hemorrhagic; and microglial activation with microglial nodules accompanied by neuronophagia, most prominently in the brainstem. Sparse T lymphocyte accumulation was observed in either perivascular regions or in the brain parenchyma. Many brains contained atherosclerosis of large arteries and arteriolosclerosis, though none had evidence of vasculitis. Eighteen (44%) contained pathologies of neurodegenerative diseases, not unexpected given the age range of our patients. Multiple fresh frozen and fixed tissues from 28 brains were examined for the presence of viral RNA and protein, using quantitative reverse-transcriptase PCR (qRT-PCR), RNAscope, and immunocytochemistry with primers, probes, and antibodies directed against the spike and nucleocapsid regions. qRT-PCR revealed low to very low, but detectable, viral RNA levels in the majority of brains, although they were far lower than those in nasal epithelia. RNAscope and immunocytochemistry failed to detect viral RNA or protein in brains. The findings indicate that the levels of detectable virus in COVID-19 brains are very low and do not correlate with the histopathological alterations. These findings suggest that microglial activation, microglial nodules and neuronophagia, observed in the majority of brains, do not result from direct viral infection of brain parenchyma, but rather likely from systemic inflammation, perhaps with synergistic contribution from hypoxia/ischemia. Further studies are needed to define whether these pathologies, if present in patients who survive COVID-19, might contribute to chronic neurological problems.

  • Mortality Among US Patients Hospitalized With SARS-CoV-2 Infection in 2020
    This report examines trends for in-hospital mortality by age among hospitalized patients with SARS-CoV-2–positive tests between March 1 and November 21, 2020? This cohort study of 503 409 patients from 209 US acute care hospitals found a decrease in in-hospital mortality among patients with SARS-CoV-2–positive tests. Mortality rates were 10.6% in March, increased to 19.7% in April, and decreased to 9.3% in November.  This large study supported findings of smaller, regional studies that reported in-hospital mortality decreased for all age groups during the pandemic period and suggests that this decrease cannot be solely attributed to hospital admission of increased proportions of younger patients.

Antiviral Therapeutics and Vaccines

  • Postvaccination SARS-CoV-2 Infections Among Skilled Nursing Facility Residents and Staff Members — Chicago, Illinois, December 2020–March 2021
    Residents and staff members of skilled nursing facilities (SNFs) are recommended to receive COVID-19 vaccine as a priority group. Twenty-two possible breakthrough SARS-CoV-2 infections occurred among fully vaccinated persons ≥14 days after their second dose of COVID-19 vaccine. Two thirds of persons were asymptomatic. A minority of persons with breakthrough infection experienced mild to moderate COVID-19–like symptoms; two COVID-19–related hospitalizations and one death occurred. No facility-associated secondary transmission was identified. SNFs should prioritize vaccination and follow recommended COVID-19 infection prevention and control practices, including following work restrictions, isolation, quarantine, testing of residents and staff members, and use of personal protective equipment.

  • Real-World Experience of Bamlanivimab for COVID-19: A Case-Control Study
    Authors conducted a retrospective case-control study across a single healthcare system of non-hospitalized patients, age 18 years or older, with documented positive SARS-CoV-2 testing, risk factors for severe COVID-19, and referrals for bamlanivimab via emergency use authorization. Cases were defined as patients who received bamlanivimab; contemporary controls had a referral order placed but did not receive bamlanivimab. The primary outcome was 30-day hospitalization rate from initial positive SARS-CoV-2 PCR. Descriptive statistics, including Chi-square and Mann-Whitney U test, were performed. Multivariable logistic regression was used for adjusted analysis to evaluate independent associations with 30-day hospitalization. Between November 20, 2020 and January 19, 2021, 218 patients received bamlanivimab (cases) and 185 were referred but did not receive drug (controls). Thirty-day hospitalization rate was significantly lower among patients who received bamlanivimab (7.3% v 20.0%, RR 0.37, 95% CI 0.21-0.64, p<0.001), and the number needed to treat was 8. On logistic regression, odds of hospitalization were increased in patients not receiving bamlanivimab and with a higher number of pre-specified comorbidities (OR 4.19 CI: 1.31-2.16, p<0.001; OR 1.68, CI: 2.12-8.30, p<0.001, respectively). Ambulatory patients with COVID-19 who received bamlanivimab had a lower 30-day hospitalization than control patients in real-world experience. We identified receipt of bamlanivimab and fewer comorbidities as protective factors against hospitalization.

Environmental Studies

  • Fitted Filtration Efficiency of Double Masking During the COVID-19 Pandemic
    This study compared the fitted filtration efficiency (FFE)
    3,4 of commonly available masks worn singly, doubled, or in combinations. Face-covering FFE was measured on 1 female volunteer (weight, 53 kg; height, 160 cm; head circumference, 56.0 cm) and 2 male volunteers with shaven faces (weight, 75 kg; height, 178 cm; head circumference, 58.5 cm; and weight, 76 kg; height, 175 cm; head circumference, 55.9 cm, respectively). In brief, FFE corresponds to the concentration of particles behind the mask expressed as a percentage of the particle concentration in a sodium chloride particle–enriched chamber atmosphere [FFE% = 100 × (1 − behind the mask particle concentration/ambient particle concentration)] measured during a series of repeated movements of the torso, head, and facial muscles as outlined by the Occupational Safety and Health Administration Quantitative Fit Testing protocol. Chamber temperatures were 22 °C to 24 °C, and relative humidities were 42% to 52%. For the doubling of each procedure and cloth mask tested, the same mask worn singly served as a control. For all cloth–procedure mask combinations, the same procedure mask (Intco) was used for all, with the single cloth mask serving as the control. procedure masks worn singly by study volunteers showed a range of mean (SD) FFE between 43% (2%) and 62% (11%). On average, across all masks and volunteers, adding a second procedure mask improved mean (SD) FFE from 55% (11%) when single masking to 66% (12%) when double masking. Single cloth masks performed less efficiently (mean [SD] FFE range, 41% [12%] to 44% [12%]) than the procedure masks. Doubling a cotton mask improved FFE but could reduce breathability. Although adding a procedure mask (mean [SD] FFE, 61% [13%]) over the cloth masks provided modest increases in their FFE (mean [SD] range, 55% [10%] to 60% [14%]), the overall performance was no different than wearing the procedure mask by itself. In contrast, wearing a procedure mask under the cloth face covering produced marked improvements in overall FFE (mean [SD] range, 66% [5%] to 81% [6%]).

Situation Dashboards


World Health Organization (WHO)

Novel Coronavirus (COVID-19) Situation from World Health Organization (WHO)

Johns Hopkins University (JHU)

Coronavirus COVID-19 Global Cases by the Center for Systems Science and Engineering (CSSE) at JHU

COVID-19 in US and Canada

1Point3Acres Real-Time Coronavirus (COVID-19) Updates in US and Canada with Credible Sources

Genomic Epidemiology COVID-19

Genomic Epidemiology of (COVID-19) Maintained by the Nextstrain team, enabled by data from GISAID.

Sources for COVID-19 Information


World Health Organization (WHO)


Centers for Disease Control, US


International Society for Infectious Diseases


This Week in Virology (TWIV)

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