COVID-19 Science Update released: June 9, 2020 Edition 20

COVID-19 Science Update

From the Office of the Chief Medical Officer, CDC COVID-19 Response, and the CDC Library, Atlanta GA. Intended for use by public health professionals responding to the COVID-19 pandemic.

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Epidemiology

PEER-REVIEWED

Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: A systematic review and meta-analysis.external icon Chu et al. Lancet (June 1, 2020).

Key findings:

  • Meta-analysis of data from observational studies indicated that physical distancing, face masks, and eye protection were protective against COVID-19, SARS, or MERS (Figure A).
    • Protective effect of distancing may double with additional meter added.
  • Use of N95 or similar respirator was highly protective; use of 12–16-layer cotton masks demonstrated protection (Figure B). (Insufficient data to assess homemade face coverings.)

Methods: Systematic review and meta-analyses of data from 44 comparative studies (25,697 patients) in healthcare and non-healthcare settings from 10 countries, published 2003–May 3, 2020. Certainty of evidence rated according to Cochrane methods and GRADE approach. Limitations: Limited data from non-healthcare settings; only 2 studies with US-based COVID-19 data, results might not be generalizable to US.

Implications: Physical distance, face masks, and eye protection prevent person-to-person spread of coronaviruses. No single intervention is fully protective; combination use is recommended.

Figure:

Association of selected public health interventions with COVID-19, SARS, or MERS.

Note: Adapted from Chu et al. Association of selected public health interventions with COVID-19, SARS, or MERS. aOR-adjusted odds ratio; CI-confidence intervals.  Blue diamonds (aORs) and blue bars (95% CIs) less than one indicate that the intervention is protective against infection. Licensed under CC-BY.

COVID-19-related economic anxiety is as high as health anxiety: Findings from the USA, the UK, and Israelexternal icon.Bareket-Bojmel et al. International Journal of Cognitive Therapy (May 29, 2020).

Key findings:

  • Among residents of the US, UK, and Israel, health- and economic-related anxiety levels were higher than anxiety from changes in daily routines and social isolation (Figure).
  • US residents reported moderate levels of health- and economic-related anxiety (~4 on 7-point scale) (Figure).

Methods: 1,200 participants (400 from US, UK and Israel each) completed an anxiety questionnaire (April 2020). Responses were provided on a 7-point Likert scale. Limitations: Used non-validated questionnaire; inability to compare scores to other populations or time points; convenience sample.

Implications: During the COVID-19 pandemic, US residents reported moderate health- and economic-related anxiety. Studies of mental health symptoms may identify populations that need emotional support and mental health services.

Figure:

Mean scores for 4 anxiety categories among 1,200 residents of the US, UK and Israel.

Note: Adapted from Bareket-Bojmel et al. Mean scores for 4 anxiety categories among 1,200 residents of the US (400), UK (400), and Israel (400). Economic-related anxiety levels were comparable to those of health-related anxiety.  Available via Nature Public Health Emergency Collection through PubMed Central.

PREPRINTS (NOT PEER-REVIEWED)

Cumulative incidence and diagnosis of SARS-CoV-2 infection in New Yorkexternal icon. Rosenberg et al. medRxiv (May 29, 2020). Published external iconin Annals of Epidemiology (June 17, 2020).

Key findings:

  • After statistical weighting, SARS-CoV-2 IgG antibodies were detected in 14% of adult New York State residents as of March 29th, corresponding to 2.1 million New Yorkers.
  • Antibody prevalence was slightly higher in men than women, and highest among those of Hispanic/Latino ethnicity and those who live in New York City (Figure).
    • Racial/ethnic disparities were noted in New York City, Westchester & Rockland Counties, and Long Island but not in the rest of New York State.
  • Only 9% (estimated) of SARS-CoV-2 infections had actually been diagnosed.

Methods: Cross-sectional seroprevalence study of >15,000 adults recruited at grocery stores across New York State (April 19–28, 2020). Seroprevalence weighted to underlying New York demographics and geographic distribution and adjusted for antibody test performance. Estimated number of SARS-CoV-2 infections (based on seroprevalence) was compared to number of diagnosed COVID-19 cases. Limitations: Likely under-sampling of vulnerable groups less likely to grocery shop, including those in long-term care facilities and hospitals or persons with disabilities.

Implications: >85% of the New York population may still be susceptible to COVID-19. Monitoring, testing, and contact tracing remain critical to limit spread of SARS-CoV-2 and address racial/ethnic disparities. Case counts based on current PCR-based testing approaches may substantially underestimate the number of SARS-CoV-2 infections.

Figure:

Prevalence of SARS-CoV-2 IgG antibodies (and cumulative incidence) in New York as of March 29th, 2020. Prevalences displayed for overall population and by demographic characteristics, after weighting and adjustment for IgG test performance.

Note: Adapted from Rosenberg et al. Prevalence of SARS-CoV-2 IgG antibodies in New York as of March 29, 2020. NH – non-Hispanic/Latino, Metro counties – Westchester and Rockland Counties, NY – New York. Data used in figure is in the public domain per communication with author.

Clinical Treatment & Management

PEER-REVIEWED

Famotidine use is associated with improved clinical outcomes in hospitalized COVID-19 patients: a propensity score matched retrospective cohort studyexternal icon. Freedberg et al. Gastroenterology (May 21, 2020).

Key findings:

  • Hospitalized patients with COVID-19 who received famotidine (a histamine-2 receptor agonist commonly used for heartburn) within 24 hours of admission were less likely to die or be intubated within 30 days (Figure).
    • Association remained after adjustment and propensity score matching (adjusted hazard ratio=0.4, 95% CI=0.2–0.9).

Methods: Single-center observational cohort study of 1,620 adults hospitalized for COVID-19 (February 25–April 13, 2020). Adjusted analysis and propensity score matching used to control for differences in baseline characteristics. Limitations: Observational, possible unmeasured confounding might account for findings; single center; methods for adjustment (including baseline characteristics used) and propensity score matching not described; biological explanation for observed association unclear.

Implications: Preliminary data that famotidine might have benefit in COVID-19 treatment. Randomized clinical trial data are needed; one clinical trial external iconinvestigating famotidine and hydroxychloroquine is underway.

Figure:

Kaplan-Meier plot showing that patients with COVID-19 who received famotidine (dashed black line) were less likely to die or be intubated during hospitalization than patients with COVID-19 who did not receive famotidine (solid black line). Patients were included in the analysis if they were alive and not intubated during first 48 hours of hospitalization (indicated by red dashed line).

Note: Adapted from Freedberg et al. Kaplan-Meier plot showing that patients with COVID-19 who received famotidine (dashed black line) were less likely to die or be intubated during hospitalization than patients with COVID-19 who did not receive famotidine (solid black line). Patients were included in the analysis if they were alive and not intubated during first 48 hours of hospitalization (indicated by red dashed line). This article was published in Gastroenterology, Vol 159, Freedberg et al., Famotidine use is associated with improved clinical outcomes in hospitalized COVID-19 patients: a propensity score matched retrospective cohort study, Page 1129-1131, Copyright the AGA Institute 2020. This article is currently available at the Elsevier COVID-19 resource center: https://www.elsevier.com/connect/coronavirus-information-centerexternal icon.

 

A randomized trial of hydroxychloroquine as postexposure prophylaxis for COVID-19.external icon Boulware et al. NEJM (June 3, 2020).

Key findings:

  • After high- or moderate-risk exposure to SARS-CoV-2, incidence of COVID-19 symptoms did not differ between participants assigned to receive 5 days of hydroxychloroquine (HCQ) post-exposure prophylaxis (49/414 [11.8%]) versus placebo (58/407 [14.3%]; p=0.35) (Figure A).
    • 66% of participants were healthcare workers, of whom 77% were exposed to infected patients or coworkers.
  • Side effects were more common among participants who received HCQ (140/349 [40.1%]) versus placebo (59/351 [16.8%]; p<0.001) (Figure B) and were predominantly gastrointestinal.
    • No arrhythmias were observed during the short course of HCQ used in this study.

Methods: Randomized, double-blind, placebo-controlled trial of HCQ among 821 asymptomatic adult participants exposed to SARS-CoV-2, March 13–May 6, 2020. Participants received 5 days of HCQ administered within 4 days of their exposure to SARS-CoV-2. Primary outcome was either PCR-confirmed infection (15%) or self-reported COVID-19-related symptoms consistent with infection within 14 days after enrollment (85%). Limitations: Participants not systematically tested for SARS-CoV-2 and asymptomatic infections were likely missed; relied on self-reported testing, illness, and hospitalization; no systematic monitoring for cardiac arrhythmias.

Implications: Evidence from this trial does not support use of HCQ for postexposure prophylaxis to prevent COVID-19.

Figure:

Proportion of participants in each trial arm comparing hydroxychloroquine (HCQ) to placebo with A) self-reported COVID-19-related symptoms and B) side effects.

Note: From Boulware et al. Proportion of participants in each trial arm comparing hydroxychloroquine (HCQ) to placebo with A) self-reported COVID-19-related symptoms and B) side effects.  From NEJM. 383:517-525; DOI: 10.1056/NEJMoa2016638. Copyright ©2020 Massachusetts Medical Society. Reprinted with permission from Massachusetts Medical Society.

Laboratory Science

PEER-REVIEWED

Implication of SARS-CoV-2 evolution in the sensitivity of RT-qPCR diagnostic assaysexternal icon. Osorio et al. Lancet Infectious Diseases (May 28, 2020).

Key findings:

  • SARS-CoV-2 is evolving. Phylogenetic sequencing of a selection of SARS-CoV-2 samples found that 79% of the viral genomic RNA sequences targeted by the primers used in current RT-qPCR diagnostic assays had undergone some extent of mutation in at least one viral sample.
    • The RNA sequence to which one such primer (China CDC_N_F) binds had undergone mutation in a substantial number of viral genome isolates (Figure, bar farthest left).
    • Mutations of RNA sequences targeted by the other primers were infrequent in the viruses that were examined (Figure).

Methods: Genomic analyses of 1,825 SARS-CoV-2 sequences collected from 24 countries and deposited in the Global Initiative on Sharing All Influenza Data (GISAID) database (as of March 31, 2020). Sequences were aligned to the SARS-CoV-2 Wuhan reference strain. Genetic mutations were determined for 33 primer binding sites along the SARS-CoV-2 genome used in RT-qPCR assays. Limitations: Potential errors in sequences submitted to GISAID.

Implications: Emerging viral mutations may render the primers used in some diagnostic assays ineffective and cause false-negative test results. Careful genomic surveillance and continued optimization of RT-qPCR primers are necessary to maintain high quality SARS-CoV-2 detection in the United States and worldwide.

Figure:

Figure shows viral genetic diversity (amount of mutation) in 33 primer binding sites used in RT-qPCR diagnostic assays across 1,825 SARS-CoV-2 genomes isolated from humans in 24 countries. Each bar represents the extent of genetic mutations of a specific primer binding site.

Note: Adapted from Osorio et al. Viral genetic diversity (amount of mutation) in 33 primer binding sites used in RT-qPCR diagnostic assays across 1,825 SARS-CoV-2 genomes isolated from humans in 24 countries. Each bar represents the extent of mutation of a primer binding site. This article was published in Lancet Infectious Diseases, Osorio et al., Implication of SARS-CoV-2 evolution in the sensitivity of RT-qPCR diagnostic assays, Copyright Elsevier 2020. This article is currently available at the Elsevier COVID-19 resource center: https://www.elsevier.com/connect/coronavirus-information-centerexternal icon.

In Brief

Disclaimer: The purpose of the CDC COVID-19 Science Update is to share public health articles with public health agencies and departments for informational and educational purposes. Materials listed in this Science Update are selected to provide awareness of relevant public health literature. A material’s inclusion and the material itself provided here in full or in part, does not necessarily represent the views of the U.S. Department of Health and Human Services or the CDC, nor does it necessarily imply endorsement of methods or findings. While much of the COVID-19 literature is open access or otherwise freely available, it is the responsibility of the third-party user to determine whether any intellectual property rights govern the use of materials in this Science Update prior to use or distribution. Findings are based on research available at the time of this publication and may be subject to change.

 

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Page last reviewed: November 5, 2020
Content source: Office of the Chief Science Officer - COVID-19