People over 65 are more likely to experience a second bout with the virus, according to a large study of medical records.The vast majority of people who recover from Covid-19 remain shielded from the virus for at least six months, researchers reported on Wednesday in a large study from Denmark.Prior infection with the coronavirus reduced the chances of a second bout by about 80 percent in people under 65, but only by about half in those older than 65. But those results, published in the journal Lancet, were tempered by many caveats.The number of infected older people in the study was small. The researchers did not have any information beyond the test results, so it’s possible that only people who were mildly ill the first time became infected again and that the second infections were largely symptom-free.Scientists have said that reinfections are likely to be asymptomatic or mild because the immune system will suppress the virus before it can do much damage. The researchers also did not assess the possibility of reinfection with newer variants of the virus.Still, the study suggests that immunity to a natural infection is unpredictable and uneven, and it underscores the importance of vaccinating everyone — especially older people, experts said.“You can certainly not rely on a past infection as protecting you from being ill again, and possibly quite ill if you are in the elderly segment,” said Steen Ethelberg, an epidemiologist at Statens Serum Institut, Denmark’s public health agency.Because people over 65 are at highest risk of severe disease and death, he said, “they are the ones we are most eager to protect.”Rigorous estimates of second infections have generally been rare because many people worldwide did not initially have access to testing, and laboratories require genetic sequences from both rounds of testing to confirm a reinfection.But the findings are consistent with those from experiments in a wide variety of settings: sailors on a fishing trawler in Seattle, Marine Corps recruits in South Carolina, health care workers in Britain and patients at clinics in the United States.The new study’s design and size benefited from Denmark’s free and abundant testing for the coronavirus. Nearly 70 percent of the country’s population was tested for the virus in 2020.The researchers looked at the results from 11,068 people who tested positive for the coronavirus during the first wave in Denmark between March and May 2020. During the second wave, from September to December, 72 of those people, or 0.65 percent, again tested positive, compared with 3.27 percent of people who became infected for the first time.That translates to a 80 percent protection from the virus in those who had been infected before. The protection fell to 47 percent for those over 65. The team also analyzed test results from nearly 2.5 million people throughout the epidemic, some longer than seven months after the first infection, and found similar results.“It was really nice to see that there was no difference in protection from reinfection over time,” said Marion Pepper, an immunologist at the University of Washington in Seattle.She and other experts noted that while 80 percent might not seem superb, protection from symptomatic illness was likely to be higher. The analysis included anyone who was tested, regardless of symptoms.“A lot of these will be asymptomatic infections, and a lot of these will likely be people who have a blip of virus,” noted Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai in New York. “Eighty percent risk reduction against asymptomatic infection is great.”The findings indicate that people who have recovered from Covid-19 should get at least one dose of a coronavirus vaccine to boost the level of protection, Dr. Krammer added. Most people produce robust immune response to a natural infection, “but there’s a lot of variability,” he said. Following vaccination, “we don’t see variability — we see very high responses in basically everybody, with very few exceptions.”Experts were less convinced by the results in people over 65, saying the findings would have been more robust if the analysis had included more people from that age group.“I wish it had actually been broken down into specific decades over 65,” Dr. Pepper said. “It would be nice to know whether the majority of people who were getting reinfected were over 80.”The immune system grows progressively weaker with age, and people over 80 typically mount weak responses to infection with a virus. The lower protection in older people seen in the study is consistent with those observations, said Akiko Iwasaki, an immunologist at Yale University.“I think we kind of tend to forget how the vaccines have been pretty amazing in offering protection in this age group, because you can see that natural infection doesn’t confer the same kind of protection,” she said. “This really does emphasize the need to cover older people with the vaccine, even if they have had Covid first.”

An official investigation will be published on Thursday 18 March, looking into the misuse of do not resuscitate orders. Throughout the pandemic charities have highlighted that the orders, which limit the medical help that people can receive, have been repeatedly placed on people with learning disabilities without their families being consulted. People with learning disabilities are up to six imes more likely to die of Covid than the general population. The BBC has spoken to one family who say they didn’t know their sister was given a do not resuscitate order until she died.

A groundbreaking new study led by University of Minnesota Twin Cities researchers from both the College of Science and Engineering and the Medical School shows for the first time that lab-created heart valves implanted in young lambs for a year were capable of growth within the recipient. The valves also showed reduced calcification and improved blood flow function compared to animal-derived valves currently used when tested in the same growing lamb model.
If confirmed in humans, these new heart valves could prevent the need for repeated valve replacement surgeries in thousands of children born each year with congenital heart defects. The valves can also be stored for at least six months, which means they could provide surgeons with an “off the shelf” option for treatment.
The study was published today in Science Translational Medicine, an interdisciplinary medical journal by the American Association for the Advancement of Science (AAAS). The valve-making procedure has also been patented and licensed to the University of Minnesota startup company Vascudyne, Inc. (Stillwater, Minn.).
“This is a huge step forward in pediatric heart research,” said Robert Tranquillo, the senior researcher on the study and a University of Minnesota professor in the Departments of Biomedical Engineering and the Department of Chemical Engineering and Materials Science. “This is the first demonstration that a valve implanted into a large animal model, in our case a lamb, can grow with the animal into adulthood. We have a way to go yet, but this puts us much farther down the path to future clinical trials in children. We are excited and optimistic about the possibility of this actually becoming a reality in years to come.”
Currently, researchers have not been able to develop a heart valve that can grow and maintain function for pediatric patients. The only accepted options for these children with heart defects are valves made from chemically treated animal tissues that often become dysfunctional due to calcification and require replacement because they don’t grow with the child. These children will often need to endure up to five (or more) open heart surgeries until a mechanical valve is implanted in adulthood. This requires them to take blood thinners the rest of their lives.
In this study, Tranquillo and his colleagues used a hybrid of tissue engineering and regenerative medicine to create the growing heart valves. Over an eight-week period, they used a specialized tissue engineering technique they previously developed to generate vessel-like tubes in the lab from a post-natal donor’s skin cells. To develop the tubes, researchers combined the donor sheep skin cells in a gelatin-like material, called fibrin, in the form of a tube and then provided nutrients necessary for cell growth using a bioreactor.

A long noncoding RNA whose function was previously unknown turns out to play a vital role in mobilizing the immune response following a bone marrow transplant or solid organ transplantation.
This RNA molecule, cataloged in scientific databases simply as Linc00402, helps activate immune defenders known as T cells in response to the presence of foreign human cells, according to a new study by researchers at the University of Michigan Rogel Cancer Center and Michigan Medicine.
The investigation, which included samples from more than 50 patients who underwent a bone marrow or heart transplant, suggests inhibiting the RNA therapeutically might improve outcomes for transplant recipients. Their findings appear in Science Translational Medicine.
Study lead author Daniel Peltier, M.D., Ph.D., is a pediatric bone marrow transplant physician at U-M.
“We see a lot of graft-versus-host disease — or GVHD — which is a potentially fatal complication that can happen after transplant when T cells in the donor’s blood see the transplant recipient’s cells as invaders and attack them,” he says. “Unfortunately, the medicines we use to prevent GVHD suppress the immune system and can raise the risk of a cancer relapse or infection, and they also have other side effects.”
In taking a deep dive into the biology, Peltier and his colleagues hoped to find a way of targeting just the problematic components of the immune system that cause GVHD.

The coronavirus’ structure is an all-too-familiar image, with its densely packed surface receptors resembling a thorny crown. These spike-like proteins latch onto healthy cells and trigger the invasion of viral RNA. While the virus’ geometry and infection strategy is generally understood, little is known about its physical integrity.
A new study by researchers in MIT’s Department of Mechanical Engineering suggests that coronaviruses may be vulnerable to ultrasound vibrations, within the frequencies used in medical diagnostic imaging.
Through computer simulations, the team has modeled the virus’ mechanical response to vibrations across a range of ultrasound frequencies. They found that vibrations between 25 and 100 megahertz triggered the virus’ shell and spikes to collapse and start to rupture within a fraction of a millisecond. This effect was seen in simulations of the virus in air and in water.
The results are preliminary, and based on limited data regarding the virus’ physical properties. Nevertheless, the researchers say their findings are a first hint at a possible ultrasound-based treatment for coronaviruses, including the novel SARS-CoV-2 virus. How exactly ultrasound could be administered, and how effective it would be in damaging the virus within the complexity of the human body, are among the major questions scientists will have to tackle going forward.
“We’ve proven that under ultrasound excitation the coronavirus shell and spikes will vibrate, and the amplitude of that vibration will be very large, producing strains that could break certain parts of the virus, doing visible damage to the outer shell and possibly invisible damage to the RNA inside,” says Tomasz Wierzbicki, professor of applied mechanics at MIT. “The hope is that our paper will initiate a discussion across various disciplines.”
The team’s results appear online in the Journal of the Mechanics and Physics of Solids. Wierzbicki’s co-authors are Wei Li, Yuming Liu, and Juner Zhu at MIT.

A new study has found that about 35% of Americans with a cancer history had an elevated risk of cardiovascular disease in the next decade, compared with about 23% of those who didn’t have cancer.
Based on a risk calculator that estimates a person’s 10-year chances of developing heart disease or stroke, researchers from The Ohio State University found that the average estimated 10-year risk for a cancer survivor was about 8%, compared to 5% for those who didn’t have a history of cancer.
The new study appears in the journal PLOS ONE.
“We know that obesity, cancer and cardiovascular disease share some common risk factors, and in addition to those shared risk factors, cancer patients also receive treatments including radiation and chemotherapy that can affect their cardiovascular health — we call that cardiotoxicity,” said lead researcher Xiaochen Zhang, a PhD candidate in Ohio State’s College of Public Health.
But those risks may be underestimated or poorly understood, leading Zhang and fellow researchers to urge steps to boost recognition among health care providers and their patients.
“The good news is that we’re getting really good at treating cancer and we have more survivors, but we need to start thinking more carefully about the non-cancer risks following a diagnosis, one of which is cardiovascular disease,” said study senior author Ashley Felix, an associate professor of epidemiology at Ohio State.

Older age at the time of conception and alcohol consumption during pregnancy have long been known to impact fetal development.
Now, a new report published in Proceedings of the National Academy of Sciences suggests older age and alcohol consumption in the year leading up to conception also may have an impact by epigenetically altering a specific gene during development of human eggs, or oocytes.
Although the study did not determine the ultimate physical effects of this change, it provides important insights into the intricate relationship between environmental exposures, genetic regulation and human development.
“While the outcome of the change isn’t clear, our findings give us a valuable look into how environmental factors affect gene regulation through epigenetics and imprinting,” said Peter A. Jones, Ph.D., D.Sc. (hon), Van Andel Institute chief scientific officer and the study’s senior author. “A better understanding of these complex processes further our understanding of health and disease and — one day — may be the foundation for new disease prevention measures.”
Today’s study centers on a gene called nc886, which is one of about 100 “imprinted” genes that pass from the mother to the fetus. Imprinted genes retain important chemical tags applied by either the mother or the father before conception. The result is an “epigenetic memory” through which non-genetic information, such as maternal age, may flow directly from parent to offspring. To date, nc886 is the only known imprinted gene that exhibits variation in the likelihood of imprinting based on maternal factors.
Using data from 1,100 mother-child pairs from South Africa, Jones and colleagues found the imprinting of nc886 was increased in older mothers but decreased in mothers who drank alcohol the year before conception. The team also investigated cigarette smoking but found no impact on imprinting of nc886.
A 2018 study published by Jones and his collaborators demonstrated that failure to imprint nc886 was associated with higher body mass in children at five years of age. Research by other groups also have linked failure to imprint nc886 with increased survival in people with acute myeloid leukemia, an aggressive type of blood cancer. Most recently, a group in Taiwan found that lack of imprinting on nc886 may reduce response to an anti-diabetic drug.
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England’s deputy chief medical officer Prof Jonathan Van-Tam has said the Oxford-AstraZeneca vaccine is safe and saves lives, after concerns in Europe about it increasing the risk of blood clots.He urged people to take up their vaccine offer, saying “vaccines don’t save lives if they’re in fridges… they only save lives if they’re in arms” and compared the risks of side effects to those associated with other drugs such as paracetamol.