Coronavirus vaccine shows rapid immune response in its first human trial

The vaccine did not cause any serious adverse effects

The following is a brief 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.

Coronavirus vaccine appears safe in the first-in-human trial

A coronavirus vaccine developed by CanSino Biologics appears to be safe and induced a rapid immune response in its first human trial, Chinese researchers reported on Friday in The Lancet medical journal.

First-in-human studies, known as Phase I trials, are primarily designed to test safety.

This vaccine did not cause any serious adverse effects, the researchers say, though they did report some side effects such as fever.

Furthermore, blood samples from the 108 vaccinated adults showed so-called neutralising antibodies and T-cell responses against the novel coronavirus, a sign of possible efficacy.

"These results represent an important milestone," coauthor Professor Wei Chen from the Beijing Institute of Biotechnology said in a statement.

"The ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from Covid-19. We are still a long way from this vaccine being available to all," the researcher added.

Further studies will be needed to confirm whether the vaccine protects against infection. The first such trial is underway in Wuhan, China.

Hydroxychloroquine tied to higher death risk in hospitalised patients

In an observational study of more than 96,000 Covid-19 patients at 671 hospitals on six continents, the malaria drug hydroxychloroquine was tied to an increased risk of death, researchers reported on Friday.

It was not clear whether taking the drug provided patients with any benefit, according to their paper in The Lancet.

Overall, 14,888 patients received hydroxychloroquine or chloroquine, with or without an antibiotic, and 81,144 did not receive those drugs.

Randomised placebo-controlled studies are needed to clarify the risks and benefits of the decades-old drug in the treatment of Covid-19, the researchers said.

Tests on hamsters show face masks reduce Covid-19 transmission risk

Many such trials are underway.

The University of Minnesota may have some results next week, from two studies testing whether hydroxychloroquine is useful for preventing infection in people exposed to the virus and whether it alleviates Covid-19 symptoms. Other placebo-controlled trial results are expected to start later this summer.

Blood vessel damage may explain clots in Covid-19 patients

A study published on Thursday in The New England Journal of Medicine helps explain why blood clots develop more often in Covid-19 patients.

It appears that the virus can severely damage patients' blood vessels, causing the blood to clot as it flows past. In studies of lungs from seven patients who died of Covid-19, researchers found damage to tiny air sacs in the lung called alveoli.

They also found severe injury to blood vessel linings, which was associated with the virus in the cells of blood vessels and disrupted cell membranes. Compared with the lungs of patients who died of influenza, the Covid-19 lungs had far more extensive injuries.

In addition, the healing reaction a process of new vessel growth called intussusceptive angiogenesis was 30 times higher than normal in the Covid-19 lungs, study co-author Dr William Li, medical director of the Angiogenesis Foundation, said in a statement. All of these factors contribute to blood clots, his team reports.

"One of the great mysteries of Covid-19 has been why blood clots, or thromboses, form in some patients," said Li.

"These clots can become lethal because they severely compromise blood flow not only in the lungs but also in other organs such as the brain and heart, among other issues. Our research is the first to show that these clots are associated with damaged blood vessels."

Simulated sunlight inactivates the coronavirus on surfaces

Simulated sunlight rapidly inactivates the novel coronavirus on non-porous surfaces like stainless steel, according to researchers from the Department of Homeland Security Science and Technology Directorate's National Biodefense Analysis and Countermeasures Center (NBACC).

"These results suggest that natural sunlight may be effective for significantly reducing the amount of virus on exposed surfaces, such as mailboxes, playground equipment, and shopping carts left outdoors in the sunlight," a spokesman for the researchers told Reuters.

While significant reductions of the virus were observed after just a few minutes of simulated sunlight, the risk of exposure from contact with surfaces may not be fully eliminated, the researchers cautioned in the Journal of Infectious Diseases.

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More research is needed on how much virus is shed onto surfaces from infected individuals, how easily the virus is transferred from surfaces, and what amount is needed to cause infection.

Hold off on blanket ‘DNR’ orders for critically ill Covid patients

In the desperate early days of the coronavirus pandemic, reports from China that few critically ill Covid-19 patients could be revived after a cardiac arrest led doctors in some countries to consider issuing blanket "Do Not Resuscitate" orders.

But for US Covid-19 patients, at least, that would not be appropriate, researchers said.

Adequate data is not yet available on US survival rates for in-hospital resuscitation of Covid-19 patients and the Chinese data may not be applicable, researchers wrote in a paper published on Friday in Circulation: Cardiovascular Quality and Outcomes, an American Heart Association journal.

"Early experience of the pandemic in the US reveals that about a quarter of Covid-19 patients are younger than 50 years of age and otherwise healthy. Cardiac arrest in such patients will likely have a different prognosis" than it would in older patients, said researchers.

The study authors are members of the American Heart Association "Get With The Guidelines" Resuscitation Investigators panel.