Published: 2020-05-21 03:48:08 BdST
Monkeys who survive coronavirus infection immune to reinfection
Two studies in monkeys offer some of the first scientific evidence that surviving COVID-19 may result in immunity from reinfection, as well as a positive sign that vaccines under development may succeed. In one of the new studies, researchers infected nine monkeys with the new coronavirus. After they recovered, the team exposed them to the virus again and the animals did not get sick. In the second study, the same researchers treated 25 monkeys with experimental vaccines and then exposed them to the coronavirus. In the vaccinated animals, "we saw a substantial degree of protection," Dr Dan Barouch told Reuters. Barouch, a researcher at the Centre for Virology and Vaccine Research at Harvard's Beth Israel Deaconness Medical Centre in Boston, and his colleagues published both studies on Wednesday in the journal Science.
Saliva droplets travel more than six feet on a breezy day
On breezy days, staying six feet (two meters) away from other people may not be enough to avoid saliva droplets containing the new coronavirus, according to two papers published on Tuesday. In one study, reported in the journal AIP Physics of Fluids, researchers who simulated breezes and winds calculated that under the right conditions, some saliva droplets could travel as far as 18 feet (six meters) from a coughing or sneezing person. The other report, in the Journal of Aerosol Science, also concludes that the current six-feet social-distancing policy "is not sufficient to protect people" against coronavirus exposure from coughs when it is breezy or windy. It is not known exactly how much virus it takes for a person to become infected. While studies like these are "important thought experiments," they may not reflect what is happening in the real world, Dr Amesh Adalja, from the Johns Hopkins Centre for Health Security in Baltimore told Reuters. "What we see in the real world is transmission when there is prolonged close contact, such as when people are living in the same household. I don't think this is a cause to change the public health practices regarding six feet being the distance you want to be separated from another individual."
Older noses may be more welcoming to coronavirus
New studies show that the nose may hold the answers to why children seem less vulnerable to infection with the new coronavirus, and why loss of smell is a COVID-19 symptom. One study, published on Wednesday in JAMA, found that in older people, the cells that line the inside of the nose produce more of the cell-surface protein the virus uses to enter the body, called angiotensin converting enzyme II (ACE2). A second study, conducted in mice, found that not only did nasal cells in older mice make more ACE2, but they also made more of the enzyme TMPRSS2, which the virus also needs to break into cells. Moreover, the researchers said on Wednesday in the journal ACS Chemical Neuroscience, ACE2 and TMPRSS2 are produced by the same nasal cavity cells that contribute to odor detection, which could explain why partial or total loss of the sense of smell is often an early COVID-19 symptom.
Where have all the heart and stroke patients gone?
Fewer patients are showing up at hospitals with heart attacks and strokes, and doctors worry people are staying away from emergency rooms because they fear COVID-19. In a report on Tuesday in The New England Journal of Medicine, doctors at a large health system in northern California said that since early March, weekly rates of hospitalization for heart attacks have been down by nearly half. Earlier this month, researchers who looked at US national stroke data reported in the Journal that in late March and early April, emergency radiology tests to evaluate stroke patients were down by nearly 40 percent from prior to the pandemic. Even an excruciatingly painful condition known as aortic dissection is being seen less often. At 11 New York City hospitals, rates of aortic dissection were down 76 percent in March and April compared to the previous two years, researchers reported in the Journal of the American College of Cardiology. When patients delay care for heart attacks and strokes, they have more complications. With strokes in particular, timely treatment is essential. "We need to get the message out. Hospitals are fully prepared to care for people without COVID-19, and can do so safely," Dr. Harlan Krumholz of Yale University in New Haven, Connecticut, told Reuters.