Covid-19 deadlier than flu for ICU patients

The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for Covid-19, the illness caused by the virus.

Covid-19 can be transmitted via lung transplant

The coronavirus can linger in the lungs even when swab tests of the back of the nose and throat are negative, doctors reported after unknowingly transplanting infected lungs into a patient who later died of Covid-19.

University of Michigan surgeons obtained the lungs from a deceased donor who had tested negative for the virus and had reportedly never been exposed to it. Soon afterward, the transplant recipient and one of the surgeons developed Covid-19.

The team collected a fluid sample from the patient's new lungs and compared it to a sample taken from the lungs immediately after removal from the donor, as well as to swab samples from the infected surgeon.

Genetic analyses showed the patient and surgeon had both acquired virus from the donor's lungs, the doctors reported in the American Journal of Transplantation. The surgeon had worn only a surgical mask when preparing the lungs for transplant, rather than full personal protective equipment because both donor and recipient had tested negative.

Potential lung transplant donors should all have specimens collected from deep within the lungs to be tested for the coronavirus, the report's co-author Dr Daniel Kaul said. The virus is less likely to be transmitted by other donated organs, such as the liver or the kidneys, he said.

Pregnant women infected by Covid-19 at higher rate, reveals study

For ICU patients, Covid-19 is deadlier than flu

Compared to patients critically ill with the flu, patients critically ill with Covid-19 have a far higher risk of dying in the intensive care unit (ICU), a new study found. Researchers in Mexico studied 147 patients with Covid-19 admitted to their ICU between March and October, and 94 patients admitted the year before with influenza A-H1N1.

All were in respiratory failure. Patients with flu were generally sicker when they arrived in the ICU but were more likely to survive. Their mortality rate was 22% versus 39% for the Covid-19 patients. After accounting for baseline health status and other risk factors, the Covid-19 patients had a nearly four times higher risk of death, the researchers reported on Thursday in a paper posted on medRxiv ahead of peer review.

Compared to influenza, Covid-19 causes more severe lung damage, the researchers said, with "fewer possibilities of recovery."

New variant on the rise in New York City

A new coronavirus variant that shares some similarities with worrisome variants discovered abroad is on the rise in New York City, studies show. At Columbia University, researchers were analyzing virus samples from patients at their affiliated medical center to monitor for virus variants first identified in the UK, South Africa, and Brazil.

When they looked for a particularly concerning mutation called E484K - against which current antibody therapies and vaccines are less effective - they found it in some samples. In many cases, it was not in one of the variants from abroad but a variant not seen elsewhere.

By mid-February, the new variant represented about 12% of their cases, the Columbia researchers reported on Wednesday. The variant was also described in a separate study by California Institute of Technology scientists, who analyzed virus samples collected in New York State since November. They found the new variant accounted for just 5% of samples in late January but almost 28% by late February. Both reports were posted on medRxiv ahead of peer review.

Some common-cold antibodies may help fight Covid-19, reveals study

On Thursday, New York City Health Commissioner Dave Chokshi said the variant's real-world effect is unknown and there is so far no indication that it reduces vaccine effectiveness.

Gyms are high-risk venues for coronavirus transmission

Gyms are high-risk venues for Covid-19 transmission and people need to be wearing masks while there, researchers warned in two papers published on Wednesday in the US Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report. One study described an August outbreak in a Chicago gym where 55 Covid-19 cases were identified among 81 attendees of indoor high-intensity exercise classes.

"Twenty-two (40%) persons with Covid-19 attended on or after the day symptoms began. Most attendees (76%) wore masks infrequently, including persons with (84%) and without Covid-19 (60%)," the authors reported.

The other study reported on three gyms in Hawaii where 21 Covid-19 cases in July were linked to two instructors who taught classes while infected. The rate of infection among students exposed before the instructors showed symptoms was 95%, the authors said.

Gym attendees should wear masks, including during high-intensity activities, even when they are 6 feet (1.83 m) or more apart, the Chicago researchers said. Facilities should enforce physical distancing, improve ventilation, and encourage attendees to isolate after symptom onset, possible exposure to Covid-19, or a positive coronavirus test result. "Exercising outdoors or virtually could further reduce SARS-CoV-2 transmission risk," they sai