COVID-19 studies look at transmission, cardiac effects, and lung ultrasound as triage
A review found most transmission to be respiratory, while a study suggested protection from eyeglasses. Data from athletes provided insight into cardiac effects, and lung ultrasound may be useful for triage. Philip A. Masters, MD, FACP, looked at how the pandemic has altered medicine.
Multiple recent studies looked at transmission of SARS-CoV-2. A review focused on the viral, host, and environmental factors that contribute to transmission was published by Annals of Internal Medicine on Sept. 17. It included research, articles, and reports published from Jan. 1 to Sept. 7 and found that respiratory transmission is the dominant mode, with proximity and ventilation being key determinants. “In the few cases where direct contact or fomite transmission is presumed, respiratory transmission has not been completely excluded,” the authors said. They also found that infectiousness peaks around a day before symptom onset and declines within a week of symptom onset, and that infectiousness is heterogeneous among patients, with most not transmitting at all and some others being superspreaders. Another study, published as a brief report by JAMA Ophthalmology on Sept. 16, suggested that eyeglasses might be associated with reduced spread of the virus. The cohort study included 276 patients hospitalized with COVID-19 in China. It found that only 5.8% of them had myopia and wore glasses at least eight hours a day while a previous study had found that 31.5% of the population of the province had myopia. “These findings suggest that the eye may be an important infection route for COVID-19, and more attention should be paid to preventive measures such as frequent hand washing and avoiding touching the eyes,” the authors said. An accompanying editorial cautioned against drawing causal conclusions from the research but noted that it is biologically plausible that eyeglasses serve as a partial barrier that reduces the inoculum of virus.
Information about the cardiac after-effects of COVID-19 was provided by a small study of competitive college athletes, published as a research letter by JAMA Cardiology on Sept. 11. All 26 tested positive for SARS-CoV-2; none were hospitalized, and 14 were asymptomatic. After completion of recommended quarantine, the athletes underwent cardiac magnetic resonance (CMR) imaging. There were no diagnostic ST/T wave changes on electrocardiogram, and ventricular volumes and function were within the normal range by transthoracic echocardiogram and CMR imaging. Four athletes had CMR findings consistent with myocarditis. Pericardial effusion was present in two. Eight additional athletes had late gadolinium enhancement without T2 elevation, suggestive of prior myocardial injury. “Cardiac magnetic resonance imaging has the potential to identify a high-risk cohort for adverse outcomes and may, importantly, risk stratify athletes for safe participation because CMR mapping techniques have a high negative predictive value to rule out myocarditis,” said the study authors. “A recent expert consensus article recommended 2-week convalescence followed by no diagnostic cardiac testing if asymptomatic and an electrocardiogram and transthoracic echocardiogram in mildly symptomatic athletes with COVID-19 to return to play for competitive sports. However, emerging knowledge and CMR observations question this recommendation.”
Early in the course of COVID-19, point-of-care lung ultrasound may be a helpful triage tool, according to a study published by Clinical Infectious Diseases on Sept. 17. It included 80 patients with COVID-19, 91% of whom had abnormal lung ultrasounds within 24 hours of ED presentation. The proportion of involved zones was lower in the 17 patients who were successfully treated as outpatients compared with 42 who received hospital care and 21 who required intubation or died (median, 30% [interquartile range (IQR), 0% to 40%], 44% [IQR, 31% to 70%], and 70% [IQR, 50% to 88%], respectively; P<0.001). “We describe a significant relationship between the clinical severity of COVID-19 pneumonia and the anatomic extent and nature of lung pathology detected by LUS [lung ultrasound], suggesting the utility of LUS in early risk stratification of COVID-19 patients,” the authors said.
Finally, in his latest KevinMD column, ACP's Vice President of Membership and Global Engagement, Philip A. Masters, MD, FACP, shares his thoughts on how the COVID-19 pandemic has profoundly altered the practice of medicine. Dr. Masters writes, “Because of the pandemic, we now live in a world where, because of the potential for asymptomatic transmission of the virus, physically being with patients can pose a real threat not only to them, but also to us as caregivers.”