Higher stroke risk linked to asymptomatic COVID-19 in younger men
Men under 50 recovering from asymptomatic COVID have double the likelihood of acute ischemic strokes (AIS) compared with men of the same age without COVID infection, according to a study last week in JAMA Network Open.
Eighteen South Asian men were treated in Singapore for AIS a median of 54.5 days after their initial COVID-19 diagnosis. Twelve (67.7%) had no known pre-existing risk factors. While AIS is a known neurologic complication from symptomatic COVID-19, none of these men experienced respiratory symptoms during their infection.
Median stroke severity was a 5 on the National Institutes of Health Stroke Scale (those with a score lower than 4 are highly likely to have good clinical outcomes, according to MDCalc). Ten patients had large-vessel occlusion, and six of those went on to receive either intravenous thrombolysis, endovascular therapy, or both. Three patients may have had a possible cardiac source.
The researchers also found increased levels of dimerized plasmin fragment D in three patients, and two had positive results for lupus anticoagulant antibodies but no other antiphospholipid antibodies.
The cohort came from 54,485 South Asian workers living in Singapore dormitories through Oct 14, 2020, and had an AIS incidence of 82.6 per 100,000 people, or a 2.16 rate ratio (95% confidence interval, 1.36 to 3.48) compared with a matched cohort of non-COVID men from 2018 (38.2 cases per 100,000). Overall, Singapore's dormitory workers accounted for 94.1% of the city-state's cases.
"This case series suggests that the risk for AIS is higher in adults 50 years or younger during the convalescent period of a COVID-19 infection without respiratory symptoms," write the researchers. "Acute ischemic stroke could be part of the next wave of complications of COVID-19, and stroke units should be on alert and use serological testing, especially in younger patients or in the absence of traditional risk factors."
Apr 22 JAMA Netw Open study
Studies detail likely COVID-19 aerosol spread in vans, car
Two new studies suggest infectious COVID-19 aerosols can travel in passenger cars and vans.
The first study, from Clinical Infectious Diseases, found that two Cleveland-area van drivers traveling to a hospital 2 hours away most likely spread COVID-19 to their passengers. SARS-CoV-2 strains between infected passengers and their respective drivers were closely related, and in a simulation using fluorescent microspheres, airflow transported both small and larger droplets greater than 3 meters from the front to the back of the van.
The same van was used in both trips, one on Dec 2, 2020, and one on Jan 23, 2021. Physical distancing was followed as closely as possible, but the van's windows were closed while the heaters were operating with a medium fan speed.
In December, the first driver transported four passengers one day prior to symptom onset, and three passengers tested positive for COVID-19 despite everyone using face masks. The second driver transported three passengers on the day of symptom onset and did not wear a face mask. One of his three passengers tested positive for COVID.
Apr 24 Clin Infect Dis study
The second study, published in the International Journal of Infectious Diseases, found that a woman in her 20s with mild COVID-19—no fever or cough—transmitted infectious viral aerosols 0.25 to 0.5 micrometers in size while driving a car for 15 minutes.
University of Florida researchers instructed her not to wear a mask, and she operated the car's air conditioning while the windows were closed. To measure SARS-CoV-2 particles, a personal cascade impactor sampler was clipped to the sun visor above the front passenger seat for the duration of the drive and 2 hours after.
"Our data highlight the potential risk of SARS-CoV-2 transmission by minimally symptomatic persons in the closed space inside of a car and suggest that a substantial component of that risk is via aerosolized virus," the researchers write. The scientists detected viral RNA in respiratory secretions of all sizes but were able to grow viable virus only from the smallest particles—those 0.25 to 0.5 micrometers in diameter.
Apr 23 Int J Infect Dis study