Coronavirus disease (COVID-19) is a multifaceted infectious disease. While, at the start of the global pandemic, it was assumed that COVID-19 was primarily a disease of the lungs, it is now known that several functional systems in the human body are affected following infection with the pathogen SARS-CoV-2. One of these functional systems is blood clotting. COVID-19 patients have an increased risk of thromboses and embolisms, such as strokes, pulmonary or myocardial infarctions, and even deep vein thromboses. The use of drugs that inhibit blood clotting has been part of the treatment guidelines for COVID-19 since July 2020. “These complications during hospitalisation have a direct impact on the well-being of patients and increased the risk of dying from COVID-19,” reports David Pereyra from MedUni Vienna’s Department of General Surgery, who is first author of the publication. The underlying coagulopathy is still not fully understood.

COVID-19 triggers unique clotting problems

“The coagulopathy observed in COVID-19 patients is novel and differs in many respects from previously known coagulation problems,” says Alice Assinger, group leader at the Institute of Vascular Biology and Thrombosis Research at the Medical University of Vienna and last author of the publication, “COVID-19-associated coagulopathy displays characteristics that, although partially comparable with other coagulation diseases, cannot be fully explained by them.” Alice Assinger’s group therefore started to look for an explanation for this sub-condition of COVID-19 in the spring of 2020, in an early phase of the pandemic.

In a multi-centre analysis of COVID-19 patients in Vienna, Linz and Innsbruck, the group observed that COVID-19-associated coagulopathy occurs almost exclusively in patients requiring intensive care or in patients who die as a result of COVID-19. Although anticoagulant drugs improve the survival of COVID-19 patients, they show no effect on immunological processes related to blood coagulation (immunothrombosis).

Low-molecular-weight heparin curtails duration of infection

The analyses showed, however, that the period of active SARS-CoV-2 infection is curtailed in patients treated with low-molecular-weight heparin, the most commonly used anticoagulant. “In patients who receive this drug, infection time is an average of four days shorter than in patients who are not treated with low-molecular-weight heparin. We were surprised to see that low-molecular-weight heparin may have a direct effect on coronavirus and its infectivity,” said David Pereyra. Experimental data show that heparin can inhibit the ability of SARS-CoV-2 to bind to cells, thereby preventing them from being infected.

These observations were made in the context of a close collaboration between the three hospitals involved — the Favoriten Hospital in Vienna, the Innsbruck Regional Hospital Innsbruck and the Johannes Kepler University Hospital in Linz — as well as through the active exchange between basic researchers and clinicians,” says Alice Assinger, underscoring the relevance of good cooperation during the COVID-19 pandemic for a better understanding of the disease and its treatment.

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Materials provided by Medical University of Vienna. Note: Content may be edited for style and length.

The study finds that 90% of current COVID patients’ rooms had detectable coronavirus on at least one surface, and that the virus was still detectable days later on certain surfaces, especially TV remote controls and nurse call buttons.

In all, 28% of the more than 2,000 samples taken from inside and near the rooms of 104 COVID patients turned up positive for coronavirus RNA. The researchers did not test to see if the viruses on the swabs were capable of causing an infection but it can help identify surfaces that need cleaning and inform infection prevention policies.

Reassuringly, the study also finds that the virus was rare or not detectable on surfaces outside the COVID patients’ rooms — probably reflecting the aggressive infection prevention protocols in COVID units. The study was conducted by University of Michigan researchers in four Michigan nursing homes between October 2020 and January 2021 when the state had a prolonged surge of cases.

“These data show that coronavirus is ubiquitous and persistent in the rooms of nursing home residents with COVID-19, and highlight the ongoing importance of rigorous cleaning and protection of staff and visitors,” said Lona Mody, M.D., M.Sc., the study’s first author and leader of nursing home infection prevention research at Michigan Medicine’s Department of Internal Medicine, Division of Geriatric and Palliative Medicine as well as VA Ann Arbor Healthcare System.

She worked with Emily Martin, Ph.D., of the U-M School of Public Health, and members of their teams and the staff of the four nursing homes to conduct the study.

One-third of the people in the United States who have died from COVID-19 have been nursing home residents, mainly in the early months of the pandemic.

Now, despite high rates of vaccination among nursing home residents, and growing vaccination among nursing home staff, the risk to unvaccinated patients, staff and visitors, and the risk of breakthrough cases among chronically ill, recently hospitalized and frail elderly residents, is still significant.

All of the patients had been diagnosed with COVID in the past two weeks and were staying in dedicated COVID units to keep them away from other nursing home residents. Nearly one in four had been in the hospital in the past month.

More than half of the patients had dementia, and most needed extensive help with bathing, dressing and eating. Half of the patients were short-stay residents of the nursing home, and by February nearly a third of the sample had gone home.

The more independently the patients could move or function, the higher the chance that surfaces such as bed and TV remote controls, nurse call buttons, windowsills and doorknobs had persistent coronavirus present. Very few positive swabs turned up in the sitting areas, nurses’ stations and elevator buttons nearest the COVID units.

The study was funded by the National Institute on Aging (3P30AG024824-16S1AG041780, AG050685, AG024824).

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Materials provided by Michigan Medicine – University of Michigan. Original written by Kara Gavin. Note: Content may be edited for style and length.

Now, researchers from the University of Copenhagen have come a significant step closer, as they have found an important difference between naturally acquired immunity and immunity following vaccination.

“The antibodies which the body produces when you have been infected with malaria look different from those produced by the body when you have been vaccinated. And that probably means that our immune system has a more efficient response when we have been naturally infected than when we are vaccinated against malaria,” says Lars Hviid, Professor at the Department of Immunology and Microbiology.

“Natural killer cells”

The immune system can trigger various mechanisms in order to defend the body. The usual defence against infections with parasites, viruses and bacteria consists of so-called macrophages.

“When we are exposed to an attack from the outside, the immune system can produce antibodies that attach to the foreign body that needs to be fought. They are then recognised by some small cells called macrophages, which are attracted to the antibody and eat the bacterium or virus. This is basically how immunity to most infectious diseases works,” explains Lars Hviid.

But, now, researchers have discovered that immunity to malaria seems to work differently. Here, the body’s immune system uses some other types of cells to fight an infection with the malaria parasite.

“We have found that the antibodies look different, depending on whether you have been vaccinated or infected. And that means that the body launches some other defence mechanism as, instead, it uses what we call natural killer cells,” says Lars Hviid.

More in common with cancer

Natural killer cells are usually known to researchers as one of the body’s best weapons to fight cancer cells. But, now, it seems that the defence against malaria has features in common with the immune system against cancer.

“In popular terms, you could say that the immune system has a more tailored defence against malaria than against other typical infections. Maybe we have evolved in this way because it is such a contagious and deadly disease — that is difficult to guess,” says Lars Hviid.

The researchers made the findings by comparing blood samples from Ghanaian people who had been infected with malaria with blood samples from people who participated in Phase 1 clinical trials of an experimental malaria vaccine.

He explains that the new knowledge may be used to develop new and improved malaria vaccines.

“Our study points to a new strategy for developing even better malaria vaccines in the future. Because, now, we know how the body mobilises the defence with natural killer cells, and we can imitate that with vaccines,” he says.

He looks forward to being able to test — together with other researchers — whether a future malaria vaccine will be able to utilise natural killer cells instead of the macrophages that the current vaccines use.

The study also illustrates how volcanic eruptions can profoundly impact vulnerable or unstable regions and highlights the need to prepare for future eruptions.

The research, which combines historical evidence with polar ice-core records of volcanic eruptions, was led jointly by historians and environmental scientists from Trinity College Dublin and Zhejiang University, China. It will be published today in Communications Earth & Environment, a new high-profile journal from Nature Portfolio.

Scientists have identified explosive volcanic eruptions as one of the most important drivers of dramatic changes in climate, often triggering sudden cooling and drying that can cause livestock death and crop damage. However, our understanding of the role played by such abrupt climate shocks in state or societal collapse has been limited by the precision and accuracy of dating of available historical and climate evidence.

Dr Francis Ludlow, Associate Professor of Medieval Environmental History at Trinity, who jointly led the study, commented:

“China has a remarkably long and richly documented history of multiple ruling dynasties, including major world powers like the Tang Dynasty, which collapsed in 907 CE, or the Ming Dynasty, which collapsed in 1644. With so many precisely dated collapses, we can look not just at individual cases of collapse that may or may not have followed a change in climate, but rather look simultaneously at many collapses to see whether there is a repeated pattern where a change in climate was followed by collapse. This can tell us whether climatic change played a very minor role in dynastic collapse, or whether it posed a systematic threat to these powerful and sophisticated societies.”

The study compared the dates of volcanic eruptions gleaned from ice-core measurements of sulphate deposited on the polar icesheets with the dates known from historical records of Chinese dynastic collapse across the first two millennia of the Common Era. This exercise found that 62 of the 68 dynastic collapses were closely preceded by at least one volcanic eruption.

John Matthews, postdoctoral fellow at the Trinity Centre for Environmental Humanities and co-author on the paper, explained:

“Researchers have identified a lot of historical eruptions through sulphate deposits in the polar ice, so we expect that some collapses will have been preceded by eruptions purely by chance. To convince ourselves we were seeing something significant, we ran the numbers and found there would be just a 0.05% chance of seeing so many collapses preceded by so many eruptions if that had actually happened randomly. This study shows a repeated link between volcanic eruptions and dynastic collapse.”

Some dynasties, the authors note, withstood numerous large eruptions before eventually succumbing, suggesting that the role of volcanism in collapse is far from straightforward and that dynasties were often resilient to sudden, volcanically triggered, climate shocks.

To gain further insight, the researchers assessed the role of explosive volcanism in tandem with other sources of stress or instability that a dynasty might experience by examining levels of warfare prevailing in the decades before collapse. Warfare was found to be elevated before most collapses, but the study also revealed a strong link between the magnitude of a volcanic climatic shock and the level of pre-existing stress.

“We found that even a small volcanic eruption might help trigger a collapse when pre-existing instability was high. Larger eruptions, however, could trigger a collapse even when pre-existing instability was minimal. So as ever, historical context is key to understanding how climate can impact a society. It is also clear that we should be preparing for the impacts of the next big eruption — so far in the twentieth and twenty-first centuries, the eruptions we’ve experienced have been minnows compared to some that these dynasties had to deal with.”

Chaochao Gao, Associate Professor, Zhejiang University, China, who co-led the research concluded: “This study tells us how important it is to build a resilient society to cope with the natural hazards that we face, be they volcanically-induced or otherwise.”