Top 10: August 13

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By Christian Hoffmann &
Bernd S. Kamps

13 August

Epidemiology

Steinberg J, Kennedy ED, Basler C, et al. COVID-19 Outbreak Among Employees at a Meat Processing Facility — South Dakota, March–April 2020. MMWR Morb Mortal Wkly Rep 2020;69:1015–1019. Full-text: http://dx.doi.org/10.15585/mmwr.mm6931a2

Detailed report of an outbreak in a meat processing facility in South Dakota. From March 16 to April 25, 25.6% (929) of employees and 8.7% (210) of their contacts were diagnosed with COVID-19; two employees died. The highest attack rates occurred among employees who worked < 6 feet (2 meters) from one another on the production line.

 

Virology

Starr TN, Greaney AJ, Hilton SK, et al. Deep mutational scanning of SARS-CoV-2 receptor binding domain reveals constraints on folding and ACE2 binding. Cell August 11, 2020. Full-text: https://doi.org/10.1016/j.cell.2020.08.012

The receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein mediates viral attachment to ACE2 receptor, and is a major determinant of host range and a dominant target of neutralizing antibodies. These researchers from Seattle have systematically changed every amino acid in the RBD and determine the effects of the substitutions on Spike expression, folding, and ACE2 binding. The work identifies structurally constrained regions that would be ideal targets for COVID-19 countermeasures and demonstrates that mutations in the virus which enhance ACE2 affinity can be engineered but have not, to date, been naturally selected during the pandemic.

 

Pathogenesis

Brest P, Refae S, Mograbi B, et al.  Host polymorphisms may impact SARS-CoV-2 infectivity. Trends Genetics August 10, 2020. Full-text: https://doi.org/10.1016/j.tig.2020.08.003

In their comment, the authors support the hypothesis of genetic influence on individual susceptibility to COVID-19 infection. Germinal polymorphisms may regulate the expression of the SARS-CoV-2 cellular target itself and proteases controlling the process of its shedding or, conversely, its internalization.

 

Transmission, Prevention

Sickbert-Bennett EE, Samet J, Clapp PW, et al. Filtration Efficiency of Hospital Face Mask Alternatives Available for Use During the COVID-19 Pandemic.  JAMA Intern Med. Published online August 11, 2020. Full-text: https://doi.org/10.1001/jamainternmed.2020.4221

Face masks can be old, but they must fit. This quality improvement study evaluating 29 face mask alternatives found that expired N95 respirators and sterilized, used N95 respirators can be used when new N95 respirators are not available. Other alternatives may provide less effective filtration. The performance of N95 respirators in the wrong size had a slightly decreased performance.

 

Huong NQ, Nga NTT, Long NV, et al. Coronavirus testing indicates transmission risk increases along wildlife supply chains for human consumption in Viet Nam, 2013-2014. PLoS One. 2020 Aug 10;15(8):e0237129. PubMed: https://pubmed.gov/32776964. Full-text: https://doi.org/10.1371/journal.pone.0237129

These researchers from Vietnam identified six known coronaviruses in bats and rodents, clustered in three Coronaviridae genera. Most notably among field rats, the odds of coronavirus RNA detection were highest in field rats sold and served in restaurants (55.6%, 84/151). The mixing of multiple coronaviruses, and their apparent amplification along the wildlife supply chain into restaurants, suggests maximal risk for end consumers and likely underpins the mechanisms of zoonotic spillover to people.

 

Greenhalgh T, Knight M, A’Court, et al. Management of post-acute covid-19 in primary care. BMJ 2020; 370. Full-text: https://doi.org/10.1136/bmj.m3026

Nice and pragmatic summary of the management of COVID-19 after the first three weeks (which is currently based on limited evidence). Key messages: Approximately 10% of people experience prolonged illness. Many such patients recover spontaneously (if slowly) with holistic support, rest, symptomatic treatment, and gradual increase in activity. Home pulse oximetry can be helpful in monitoring breathlessness.

 

Comorbidities

Rivinius R, Kaya Z, Schramm R, et al. COVID-19 among heart transplant recipients in Germany: a multicenter survey. Clin Res Cardiol. 2020 Aug 11. PubMed: https://pubmed.gov/32783099. Full-text: https://doi.org/10.1007/s00392-020-01722-w

A multicenter survey of all heart transplant centers in Germany evaluating the current status of COVID-19 among adult heart transplant recipients. Eight of 21 patients (38.1%) displayed a severe course needing invasive mechanical ventilation, seven of whom died.

 

Inciarte A, Gonzalez-Cordon A, Rojas J, et al. Clinical characteristics, risk factors, and incidence of symptomatic COVID-19 in adults living with HIV: a single-center, prospective observational study. AIDS. 2020 Aug 7. PubMed: https://pubmed.gov/32773471. Full-text: https://doi.org/10.1097/QAD.0000000000002643

53 out of 5683 (0.9% confidence interval 0.7-1.2%) PLWH in Barcelona were diagnosed with COVID-19. Clinical presentation, severity rate, and mortality were not dependent on any HIV-related or antiretroviral-related factor. COVID-19 standardized incidence rate was lower in PLWH than in the general population.

 

Severe COVID-19

Mustafa AK, Alexander PJ, Joshi DJ, et al. Extracorporeal Membrane Oxygenation for Patients With COVID-19 in Severe Respiratory Failure. JAMA Surg. 2020 Aug 11. PubMed: https://pubmed.gov/32780089. Full-text: https://doi.org/10.1001/jamasurg.2020.3950

According to this retrospective report on 40 patients, single-access, dual-stage venovenous ECMO with early extubation appears to be safe and effective in patients with COVID-19 respiratory failure. Ongoing studies are required, however, to further define the long-term outcomes of this approach.

 

Treatment

Bradfute SB, Hurwitz I, Yingling AV, et al. SARS-CoV-2 Neutralizing Antibody Titers in Convalescent Plasma and Recipients in New Mexico: An Open Treatment Study in COVID-19 Patients. J Infect Dis. 2020 Aug 11:jiaa505. PubMed: https://pubmed.gov/32779705. Full-text: https://doi.org/10.1093/infdis/jiaa505

This single-arm interventional trial measured neutralizing antibodies (Nab) and total antibody titers before and after CP transfusion over a 14-day period in 12 hospitalized COVID-19 patients. NAb titers in the donor CP units were low (<1:40 to 1:160) and had no effect on recipient neutralizing activity one day after transfusion. Pre-screening of CP may be necessary for selecting donors with high levels of neutralizing activity for infusion into patients with COVID-19.