New coronavirus adapts to populations, vaccine works in monkeys

The following is a brief roundup 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.

New coronavirus is adapting to different populations

A genetic analysis of samples from more than 7,500 people infected with COVID-19 suggests that as the new coronavirus spreads quickly around the world, it is adapting to its human hosts, researchers reported on Tuesday in the medical journal Infection, Genetics and Evolution. They found almost 200 recurrent genetic mutations of the new coronavirus - SARS-CoV-2 - that show how it may be evolving as it spreads in people.

"All viruses naturally mutate," Francois Balloux of University College London, who co-led the research, told Reuters. "Mutations in themselves are not a bad thing and there is nothing to suggest SARS-CoV-2 is mutating faster or slower than expected. So far, we cannot say whether SARS-CoV-2 is becoming more or less lethal and contagious."

Experimental vaccine protects macaques from SARS-CoV-2 infection

In macaque monkeys, an experimental vaccine for the novel coronavirus safely induced antibodies that blocked several different SARS-CoV-2 strains, Chinese researchers reported on Wednesday in the journal Science. The researchers say tests of their vaccine candidate, "PiCoVacc," in humans will likely begin later this year.

Blood thinners may improve survival of hospitalized COVID-19 patients

Blood thinners may improve survival odds for hospitalised COVID-19 patients, a study from New York City suggests. Researchers looked back at 2,773 patients, about one in four of whom had received a high dose of blood clot preventers.

Patients who got this treatment were more likely to survive, the researchers reported on Wednesday in the Journal of the American College of Cardiology. The difference was most pronounced among the 395 patients who needed mechanical ventilation. In this group, the death rate was 63 per cent without anticoagulants and 29 per cent when patients did get blood thinners.

The researchers note that because the study was not randomised, it cannot prove the drugs directly led to better survival. Large randomized trials are needed to confirm a benefit, researchers said, and any potential benefit needs to be weighed against the increased risk of bleeding with these drugs.

COVID-19 antibodies may not predict speed of recovery

The immune system does not always respond to SARS-CoV-2 infection the way doctors might expect, unpublished data suggest. Researchers at MD Anderson Cancer Center in Houston found that having antibodies to two important structures on the surface of the virus does not necessarily mean patients' recovery will be faster or smoother.

Raghu Kalluri, who coauthored the study, told Reuters that patients with severe COVID-19 disease being treated in intensive care units had varying levels of antibodies. In fact, some recovered patients did not have these antibodies at all, which, he said, suggests that their immune systems fought off the virus in some unknown way. The study, posted on Tuesday on the preprint server medRxiv, has not yet been peer reviewed or published in a medical journal.

Coronavirus link to loss of smell and taste may be underestimated

The true prevalence of problems with smell and taste among patients infected with the novel coronavirus may be higher than doctors realize, according to researchers who reviewed 10 studies published earlier this year.

Among a total of more than 1,600 infected patients in North America, Asia and Europe, nearly 53 per cent had diminished or loss of sense of smell, and nearly 44 per cent had problems with taste.

In the subset of studies that used particularly reliable tests to evaluate patients' ability to smell and taste, rates of dysfunction were even higher, suggesting "that the true prevalence of dysfunction in COVID-19 patients may remain underestimated," the research team wrote on Tuesday in the journal Otolaryngology - Head and Neck Surgery.

Increased awareness "may encourage earlier diagnosis and treatment of COVID-19, as well as heighten vigilance for viral spread."

Researchers list ways to ease stress of frontline caregivers

There are many well documented methods hospitals could use to help ease frontline caregivers' emotional stress, according to researchers who reviewed dozens of studies of healthcare staff working during outbreaks of emerging viruses. Broadly, they say, interventions fall into the categories of clear communication, access to adequate personal protection, adequate rest, and practical and psychological support.

Among their specific recommendations are changes to practice, such as screening stations to funnel infected patients to specific areas, redesigning of procedures that pose high risks for spread of infection, and reducing the density of patients on wards.

They wrote on Tuesday in The BMJ that interventions shown to be helpful in the earlier studies "were similar despite the wide range of settings and types of outbreaks ... and thus could be applicable to the current COVID-19 outbreak."