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.
UK variant carries higher death risk
The coronavirus variant first identified in the UK is deadlier than earlier variants, a new study confirms. Researchers tracked roughly one million individuals tested for Covid-19 from November to January in community settings, including about 3,000 who ultimately died from it.
After accounting for other factors that affect Covid-19 outcomes, patients with the new variant had a roughly 35 per cent higher risk of death, they reported on Wednesday on medRxiv ahead of peer review.
Among male patients ages 55-69, around 1-in-180 died after becoming infected with older versions of the virus. With the new variant "that's gone up to around ... 1-in-140," said co-author Nicholas Davies of the London School of Tropical Medicine & Hygiene.
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The absolute risk of death remains low under age 54, his team said. For women ages 70-84, the risk of death within 28 days went from 2.9 per cent with the original variant to 3.7 per cent with the new UK variant, and for those age 85 and older it went from 12.8 per cent to 16.4 per cent.
For males ages 70-84, the mortality rate rose from 4.7 per cent to 6.1 per cent and for older males from 17.1 per cent to 21.7 per cent. The researchers did not have data on people who were diagnosed in hospitals or on infected people who were never tested. Davies said his team is updating its analysis with more data, "and it looks like the increase in mortality may well be higher than 35 per cent."
Covid-19 vaccine in pregnancy may protect newborns
Covid-19 vaccines given to pregnant women may help protect their newborns, a case report suggests. Florida doctors described a frontline healthcare worker who received the first dose of the Moderna vaccine three weeks before going into labor. Her healthy baby girl had so-called IgG antibodies to the new coronavirus in her umbilical cord blood. Finding these antibodies in the baby after a single dose of the vaccine suggests
"There is potential for protection and infection risk reduction from ... maternal vaccination," The doctors said in a paper posted on Friday on medRxiv ahead of peer review. The ideal timing of vaccination during pregnancy is not clear, they said, nor is it clear how well these antibodies will protect the infant, or for how long.
US Centres for Disease Control and Prevention guidelines say that because only limited data are available on the safety of Covid-19 vaccination during pregnancy, "getting vaccinated is a personal choice for people who are pregnant."
Semen quality may be impaired after Covid-19
Young, sexually active men who recover from Covid-19 may be at risk for fertility problems, a small study from Italy suggests. Doctors who analysed semen samples from 43 such men found that in 25per cent, the semen was nearly or completely devoid of sperm.
A complete absence of sperm, or azoospermia, was "highly related to the severity of the illness: The condition was found in four out of five patients admitted to the intensive care unit," researchers reported in the journal Human Reproduction. While most of the men had fathered children, a few reported previous problems having a baby with a long-term partner, and the researchers acknowledge that they did not have any pre-Covid-19 semen samples for comparison purposes.
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Still, the researchers said their finding that one-in-four men who recovered from Covid-19 had little or no sperm in their semen suggests that "an assessment of semen quality should be recommended for men of reproductive age who are affected by Covid-19."
New clues discovered to ICU patients’ breathing problems
The lungs of Covid-19 patients in intensive care units can lack "surfactant," a substance crucial to breathing that helps oxygen in the air sacs of the lungs get transferred into blood. Researchers believe they now have new clues to explain why that occurs.
The coronavirus somehow triggers the immune system to mistakenly attack surfactant-producing cells, they reported on Sunday on medRxiv ahead of peer review. In lab experiments, they exposed healthy human lung tissue to plasma from Covid-19 patients.
So-called IgA antibodies in the plasma attacked surfactant-producing lung cells called pneumocytes, although that was only true for plasma from critically ill patients. In autopsies of deceased Covid-19 patients, the researchers found "remarkably reduced" levels of surfactant in the lungs.
Other research teams have been planning trials to see if treatment with artificial surfactant - a mixture of lipids and proteins that can be helpful in premature infants - will help ease breathing problems in severely ill Covid-19 patients. The authors of the new report say further study is also needed to see whether treatment with immunosuppressive medications might be another way to protect surfactant-producing proteins.
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