COVID-19 Scan for Oct 12, 2020

Disappointing convalescent plasma data
COVID-19 spread via sewage

Convalescent plasma doesn't cut death, hospital stays in COVID patients

A study late last week found that convalescent plasma (CP) treatment did not significantly reduce mortality, but improved hospital discharge rates for patients 65 and older. The study in Clinical Infectious Diseases is one of the first to analyze clinical outcomes for closely matched cohorts of CP and control patients. 

In convalescent plasma treatment, plasma collected from individuals who have recovered from an infection is transfused into currently infected patients to provide passive immunity. CP treatment has a long history of application for other types of infections and is in clinical use to treat COVID-19 patients. Preliminary safety data for COVID-19 CP treatment is reassuring, but the efficacy is still unclear and remains the focus of multiple ongoing randomized controlled trials.

The current study followed 241 adult COVID-19 patients—64 CP patients and 177 control patients—admitted to three Rhode Island hospitals prior to May 31 through 28 days post-admission. The two patient cohorts were matched for symptoms, demographics, and pre-existing comorbidity scores.

Data from patient electronic health records revealed no significant difference between CP and control groups for in-hospital mortality (12.5% vs 15.8%, P = 0.52) or overall rate of hospital discharge (rate ratio [RR] 1.28, 95% confidence interval [CI], 0.91 to 1.81).  

Patients 65 years or greater who received CP showed an increased rate of hospital discharge compared with those in the control group (RR 1.86, 95% CI, 1.03 to 3.36)—even more pronounced in patients receiving high-titer antibody plasma—suggesting a possible increased benefit of CP for this age-group.

"An effect specific to this age group is not entirely surprising given the increase in morbidity among the elderly with COVID-19, the waning of humoral immunity with age, and the importance of the humoral compartment of the overall immune response in combating this infection," the study authors wrote.

The study highlights the need for further research to identify optimal plasma antibody levels, timing of plasma transfusion, and patients who are most likely to benefit from CP treatment.
Oct 10 Clin Infect Dis study


Chinese study shows possible COVID-19 transmission via sewage

A COVID-19 outbreak investigation in a densely populated community in China provides evidence for possible transmission via sewage, highlighting the importance of sewage management for pandemic control.

Prior studies have identified SARS-CoV-2—the virus that causes COVID-19—in patient fecal matter, but sewage transmission has not yet been demonstrated. Today's study in Clinical Infectious Diseases examined an April outbreak in a 2,888-resident community of Guangzhou City in southern China to identify the source of infection and mode of transmission in order to recommend prevention and control measures.

A Guangzhou woman and her husband tested positive for SARS-CoV-2 in a hospital on Apr 13. The couple had frequented a market with an ongoing outbreak.

Throat and/or rectal swabs were collected from 324 people in government quarantine who were residents of the same or adjacent buildings as the primary patients (building A). From Apr 16 to Apr 21, six secondary patients (three couples) were identified among quarantined residents. The secondary patients all lived in two buildings (B and C) immediately adjacent to that of the primary patients, and none had visited the market or had any significant contact with the original patients.  

Apr 22 environmental sampling of sewage pipes and shoe bottoms in resident apartments showed high positivity rates for buildings A, B, and C. The sewage pipe for the toilet in the primary patients' residence building was observed to have a 1-square-meter hole that drained into the alleyway and soaked the entrances of building B and C. Genome sequencing of the virus from the toilet of the primary cases, sewage pipe swabs of the three buildings, and shoe-bottom dirt from all cases were 99.996% identical.

A retrospective analysis of SARS-CoV-2–positive individuals showed that working as cleaners or waste pickers, not changing to clean shoes after returning home, and handling dirty shoes after returning home were significant exposure risk factors.

The authors conclude, "These findings highlight the importance of sewage management for preventing and controlling COVID-19, especially in densely populated, low-income urban communities with poor sanitation and hygiene conditions."
Oct 12 Clin Infect Dis study

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