COVID-19 Scan for Oct 12, 2020

News brief

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

News Scan for Oct 12, 2020

News brief

FDA considers revising criteria for ranking medically important antibiotics

The US Food and Drug Administration (FDA) late last week published a concept paper outlining potential revisions to criteria that the agency uses to guide the use of medically important antimicrobial drugs in veterinary medicine.

The FDA says the proposed approach for updating the current ranking of antibiotics, which was created in 2003 under Guidance for Industry (GFI) #152, would take into account an improved understanding of antimicrobial resistance, changes in human clinical practices, and other scientific advances. The revised criteria would also more broadly consider the importance of these antibiotics in human medicine, beyond their use in treating foodborne bacterial infections.

Under the current criteria, medically important antibiotics are ranked as critically important, highly important, or important for human medicine (a fourth category includes antibiotics not important for human medicine). The FDA uses these rankings to make decisions about how these antibiotics can be used in veterinary medicine, and to assess the antibiotic resistance risks involved. The approach outlined in the concept paper proposes categorizing antibiotics into three tiers—highest impact, intermediate impact, and lowest impact—that take into consideration the potential human health impact if resistance emerges to an antibiotic in one of these tiers.

"These revised criteria are intended to better characterize the overall importance of a drug for treating human infections, whether or not they are foodborne," the FDA said in a press release. "However, in addition to this importance ranking, other risk factors would be considered as part of an overall assessment of antimicrobial resistance risks associated with the use of an antimicrobial drug in animals."

The FDA is seeking comment on the concept paper and will hold a virtual meeting to discuss the details on Oct 16.
Oct 9 FDA press release
Oct 9 FDA concept paper


Flu-like illnesses linked to higher heart and stroke risk within the month

In a study last week in the Journal of the American Heart Association, researchers analyzing New York public health data from 2004 to 2015 found an association between flu-like illness and increased risk for heart attack and stroke in adults regardless of flu vaccine effectiveness (VE).

"We found that if someone's going to have a heart attack, it's going to occur within seven days of the flu-like illness, during the acute phase," study author Amelia Boehme, PhD, MSPH, says in an American Heart Association (AHA) press release. "With stroke, we see an increased risk seven to 15 days after, similar to heart attacks. But with stroke, there is an additional higher-risk period after 30 days."

Even though a higher VE correlated with lower rates of flu-like illnesses, stroke, and myocardial infarction (heart attacks) in adults, the association remained the same. Further research is needed to determine how and why the flu vaccine affects risk, the authors wrote.

A closer look at the study pool—which was between 5,639 and 57,993 cases per year—suggested that being above 65 years of years of age did not have any effect on the association between flu-like illness and stroke, but it did for heart attacks. Another subgrouping showed that while there was no significant relationship between stroke and race, there was one between heart attacks and non-black patients.

The researchers note that although they used billing codes and autoregressive integrated moving average models across the 10 years of data, their study is limited due to its ecological nature and it did not take into account variables such as individual vaccine usage and comorbidities such as high blood pressure and diabetes.
Oct 8 J Am Heart Assoc study
Oct 8 AHA press release

This week's top reads