Long COVID changes heart rate variability, study suggests

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NIAID/ flickr

According to a small case-control study today in Scientific Reports, long COVID can affect heart rate variability (HRV) at rest and during deep breathing, adding to the evidence that persistent symptoms of the virus can be associated with cardiac and dysfunction of the autonomic nervous system (dysautonomia). This system regulates involuntary functions like heartbeat, blood pressure, and sweating.

The study, conducted by Brazilian researchers, included 21 patients with long COVID and 20 controls. Long COVID—defined by the authors as new or persistent symptoms experienced 12 or more weeks after infection—has been associated with heart palpitations, orthostatic intolerance (difficulty staying upright), dizziness, and syncope.

Dysautonomia, characterized by dysregulation of HRV, may explain the persistent symptoms observed in Long COVID patients.

"Dysautonomia, characterized by dysregulation of HRV, may explain the persistent symptoms observed in Long COVID patients," the authors wrote. "There is currently a lack of evidence demonstrating how long these autonomic symptoms persist post infection."

Mean heart rate higher with long COVID

In the study, long-COVID patients had reduced HRV at rest and during deep breathing, but mean heart rate was significantly higher in the long-COVID group than in controls. The authors observed these differences during a series of tests that measured heart rate during supine positioning and breathing exercises.

"Patients with Long COVID may present with dysautonomia characterized by an imbalance of HRV, which is reflected in the band potencies of 0.15–0.4 Hz 13, and highlights that this dysautonomia could explain the persistent symptoms observed in patients with Long COVID," said the authors.

The authors said their findings should guide treatments for long-COVID fatigue and dysautonomia. "Our findings provide a rationale for improving fatigability with interventions aimed at improving cardiac and respiratory system autonomic control, through pharmacological and non-pharmacological measures aimed at reducing the cardiovascular risk in these patients," they wrote.

"For example, cardiorespiratory rehabilitation can reduce muscle fatigue and improve cardiac autonomic function in other chronic conditions and has been the focus of numerous studies in patients with Long COVID."

Most COVID patients received antibiotics early in the pandemic, data show

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ICU patient
US Navy, Ryan M. Breede / Flickr cc

Nearly 80% of COVID-19 patients in 28 countries received early empiric antibiotics during the first year and a half of the pandemic, US and Turkish researchers reported yesterday in the International Journal of Infectious Diseases.

Using data from the Society of Critical Care Medicine Discovery VIRUS International COVID-19 Registry, the researchers looked at the rate of coinfections at admission and the rate and factors associated with early empiric antibiotic use in COVID-19 patients from January 2020 to October 2021. They focused on antibiotics administered within the first 3 days of hospitalization, particularly azithromycin, which was thought early on to have a beneficial effect when combined with hydroxychloroquine. After exclusions, 7,830 patients were included in the analysis.

The vast majority of patients (79.4%) received early empiric antibiotic treatment, with 40.2% receiving a combination of azithromycin and another antibiotic. The proportion of patients receiving early empiric antibiotic treatment fell from 84.4% in the first quarter of 2020 (January to March 2020) to 65.2% in April-June 2021. Beta-lactams, specifically ceftriaxone, were the most commonly used non-azithromycin antibiotic. Of the 7,830 patients, 5.8% had culture-proven community-acquired respiratory coinfections at the onset of hospitalization, with Staphylococcus aureus the most common (24%) pathogen isolated.

Decreasing trend over time

Multivariate analysis revealed that patients from Southeast Asia had the highest odds (odds ratio [OR], 77.8; 95% confidence interval [CI], 31.9 to 190.4) of receiving antibiotics compared with other regions. As the pandemic advanced, the OR of receiving any antibiotic treatment declined from 5.9 (95% CI, 2.7 to 13.0) to 4.1 (95% CI, 1.9 to 8.9). Diabetes, fever, and difficulty breathing were independently associated with antibiotic use.

The study authors say the decline in the frequency of early empiric antibiotic treatment over the study period could be attributed to antibiotic stewardship efforts, along with faster polymerase chain reaction test turnaround times and the failure of hydroxychloroquine-azithromycin treatment to show any benefit in COVID patients.

"Our study provides worldwide goals for antibiotic stewardship programs in COVID-19 setting as well as for future viral pandemics," they wrote. "Further research is needed to better understand the factors that influence antibiotic use during the pandemic and to optimize treatment for patients with COVID-19."

Study highlights factors linked to inappropriate antibiotics in kids

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Doctor examining child's ear
naumoid / iStock

Ear infections, a general practitioner (GP) as a prescriber, and rural settings were identified as primary drivers of inappropriate antibiotic prescribing in children treated in ambulatory care in high-income countries, according to a study published yesterday in the Journal of Antimicrobial Chemotherapy.

For the study, Belgian researchers reviewed 40 articles reporting on 30 different factors and their association with inappropriate prescribing in acutely ill children receiving ambulatory care in 15 high-income countries. They included cross-sectional studies, prospective and retrospective cohort studies, and reports from health organizations.

Appropriateness covered a range of definitions, including whether the class of prescribed antibiotic or dose was appropriate, and whether the diagnosis justified the antibiotic prescription. Factors and their association with inappropriate prescribing were categorized as patient-level, prescriber-level, environment-level, or miscellaneous.

Priorities for antibiotic stewardship

A meta-analysis of the pooled results found that diagnosis of acute otitis media (ear infection; pooled odds ratio [OR], 2.02; 95% confidence interval [CI], 0.54 to 7.48) was associated with more inappropriate prescribing compared with upper respiratory tract infections, and that GPs had 1.38 higher odds (95% CI, 1.00 to 1.89) of inappropriate prescribing compared with pediatricians. Odds of inappropriate prescribing in rural settings were 1.48 times higher (95% CI, 1.08 to 2.02) than in urban settings.

The researchers also found that older patient age and respiratory tract infection diagnosis have a tendency to be positively associated with inappropriate antibiotic prescribing, but pooling of the studies was not possible.

"Therefore, it is recommended that antimicrobial stewardship programmes prioritize these specific situations," the study authors wrote. "Several examples of antimicrobial stewardship actions include decision-support tools, audit and feedback, support for adhering to antimicrobial guidelines, fixed pack dispensing, and public awareness campaigns."

Nebraska reports 31 CWD cases as infection spreads to 3 additional counties

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White-tailed deer in field
David Marvin / Flickr cc

Chronic wasting disease (CWD) surveillance in central and north central Nebraska netted 31 positive cases in deer, including those in three new counties, during the November firearm season, Nebraska Game and Parks (NGP) said yesterday in a news release.

Hunters supplied 603 deer samples to check stations in the Sandhills, Keya Paha, Calamus East, Calamus West, and Loup West deer management units. For the first time, CWD was found in Rock, Blaine, and Thomas counties, all in the north-central part of the state.

Hunter caution urged

NGP conducts surveillance in five to seven deer management units each year, rotating to a different area each time. CWD was first found in Nebraska in 2000 in Kimball County in the west, which borders both Wyoming and Colorado. NGP has tested more than 57,000 deer and 400 elk since 1997, with 1,269 deer and 19 elk in 57 counties testing positive.

CWD prions, the infectious proteins that transmit the disease, can remain viable for months or even years in the soil.

CWD is a fatal neurodegenerative disease caused by infectious misfolded proteins called prions. While CWD is not yet known to infect humans, the Centers for Disease Control and Prevention advises hunters to not consume meat from any animal that is obviously ill or tests positive for the disease.

"CWD prions, the infectious proteins that transmit the disease, can remain viable for months or even years in the soil," NGP said in the news release. "Hunters should field dress animals at the place of kill, avoid spreading spinal cord or brain tissue to meat, and to dispose of the head (brain), spinal column, and other bones at a licensed landfill."

Quick takes: Infection-prevention staffing, avian flu in South Korea, Western equine encephalomyelitis alert

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  • The Association for Professionals in Infection Control and Epidemiology (APIC) today announced the launch of a staffing calculator to help facilities gauge infection preventionist needs. In a statement, APIC said the tool was developed following a literature review of existing infection preventionist staffing models and feedback from multiple facility surveys. The tool consists of three separate calculators that recommend staffing ratios for acute, long-term, and ambulatory care settings, based on key risk factors.
  • South Korea this week reported highly pathogenic H5N6 avian flu in poultry and wild birds, the World Organisation for Animal Health has confirmed. According to an agriculture ministry statement translated and posted by Avian Flu Diary, an infectious disease news blog, it is the first high-path avian flu detection in the country since 2018. Sporadic human infections involving H5N6 have been reported, mainly in China. The virus is known to circulate in some Asian countries. In US avian flu developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has reported more avian flu outbreak in three states, including two poultry farms in California's Sonoma County, one of which is a layer facility housing nearly 500,000 birds. Also, the virus struck a gamebird producer in South Dakota and backyard birds in Kansas.
  • The Pan American Health Organization (PAHO) yesterday published an epidemiologic alert about the risk to human health from recent detections of Western equine encephalomyelitis (WEE) in horses in several of Argentina's provinces and in some locations in Uruguay. Birds are the main hosts of the virus, which can spread to horses and humans through infected mosquitoes. At-risk groups are people who live, work, or recreate in endemic areas or locations where outbreaks are occurring. On November 30, Argentina declared a state of emergency after equine cases were reported in nine provinces, marking the country's first WEE cases since 1988. In early December, Uruguay reported equine cases in nine municipalities. Though no human cases have been reported so far, PAHO urged healthcare providers to be vigilant for patients presenting with neurologic symptoms and for cities and provinces to step up their surveillance and vector-control activities.

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