(Reuters) – 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 disease caused by the virus.
A health worker wearing a protective suit and face mask holds a plastic bag with nasal swab test tubes at a test site for coronavirus disease (COVID-19) in Thouare-sur-Loire near Nantes, France, September 29, 2020 REUTERS / Stephane Mahe
Neanderthal Genes Linked to Severe COVID-19
A group of genes passed on from extinct human cousins is linked to a higher risk of severe COVID-19, according to researchers. When comparing the genetic profiles of approximately 3,200 COVID-19 patients in the hospital and nearly 900,000 people from the general population, they found that a group of genes on chromosome 3 inherited from Neanderthals who lived more than 50,000 years ago was with a 60% higher likelihood of needing hospitalization. People with COVID-19 who have inherited this gene cluster are also more likely to need artificial respiratory assistance, said co-author Hugo Zeberg of the Max Planck Institute for Evolutionary Anthropology in a press release. The prevalence of these genes varies widely, according to a report published in Nature on Wednesday. In South Asia, about 30% of people have it, compared to about one in six Europeans. They are almost non-existent in Africa and East Asia. While the study fails to explain why these particular genes pose a higher risk, the authors conclude, “With regard to the current pandemic, it is clear that the Neanderthal gene flow is tragic.” (go.nature.com/36lHwnC)
Mosquitoes cannot transmit COVID-19
According to a study by researchers from the U.S. Department of Agriculture and Kansas State University, a mosquito that bites a person with COVID-19 cannot pass the coronavirus infection on to the next victim. Mosquitoes are notorious vectors of disease that transmit West Nile virus, Zika, and many other viruses from person to person and among animals. In laboratory experiments, the researchers allowed several species of disease-causing mosquitoes, as well as several other biting insects, to feed on blood that was contaminated with the novel coronavirus SARS-CoV-2. The virus was unable to survive or replicate itself in any of the insects, they reported in an article published on bioRxiv on the Wednesday before peer review. “Biting insects pose no risk of transmitting SARS-CoV-2 to humans or animals,” said the researchers. (bit.ly/3jgeLMw)
The Moderna vaccine passes the safety test in elderly patients
Findings from an early security study by Moderna Inc. MRNA.O The coronavirus vaccine candidate in older adults showed it elicited immune responses in similar amounts to younger adults, with side effects roughly on par with high-dose flu shots, researchers reported Tuesday in the New England Journal of Medicine. The results are reassuring, as immunity tends to weaken with age, said co-author Dr. Evan Anderson of Emory University in Atlanta told Reuters. The study included 20 adults aged 56 to 70 years and a further 20 aged 71 years and older. Side effects included headache, fatigue, body pain, chills, and pain at the injection site. In most cases, these were mild to moderate. “This is similar to what many older adults will experience with the high-dose influenza vaccine,” said Anderson. Moderna is already testing the vaccine in a large phase III study, the final phase before an emergency approval or approval is applied for. (bit.ly/3ihdvrp; reut.rs/3cL77HN)
Hydroxychloroquine does not prevent COVID-19
A malaria drug that U.S. President Donald Trump took to prevent COVID-19 failed to prevent coronavirus infections in healthcare workers in a gold standard randomized controlled trial at the University of Pennsylvania. The new study, published on Wednesday in JAMA Internal Medicine, shows that routine use of the drug hydroxychloroquine cannot be recommended to health care workers for the prevention of COVID-19. The study largely confirms the results of a similar study at the University of Minnesota that found hydroxychloroquine failed to prevent infection in people exposed to the new coronavirus. (bit.ly/3ldgMdd; bit.ly/34eErTl; reut.rs/3cM7wty)
Immune differences in children with inflammatory syndrome after COVID-19
A new study may shed light on why some teenagers develop the rare and dangerous Multisystem Inflammatory Syndrome in Children (MIS-C) after recovering from COVID-19, while most do not. The syndrome can cause severe inflammation of the blood vessels, heart, lungs, kidneys, and other organs. The immune system is more activated in children with MIS-C than in children with COVID-19, said study co-author Dr. John Wherry of the University of Pennsylvania’s Perelman School of Medicine told Reuters. However, in MIS-C patients, the activated immune system calms down quickly and symptoms often improve faster than during a battle with COVID-19. Wherry identified a possible link between a certain type of activated immune cells in children with MIS-C and some of the vascular complications seen in the disease as well as in COVID-19. “Identifying a type of immune cell associated with vascular symptoms can identify a new target (treatment) if approaches can be developed to target such cells,” he said. The study was published on medRxiv on Sunday before peer review. (bit.ly/3n2KFyp)
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Reporting by Nancy Lapid and Julie Steenhuysen; Adaptation by Bill Berkrot