UK blockade should not be lifted until Covid-19 transmission understood, scientists say | Coronavirus outbreak



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British scientists are competing to try to answer fundamental questions about the Covid-19 virus and its transmission before the government approves the lifting of the current national blockade in the near future. The researchers say that relaxing social distancing should occur only once it is understood why thousands of new disease infections are still diagnosed every day.

Such a rate means that efforts to test and trace infected contacts, a key element in the government’s anti-Covid strategy in the coming months, would quickly be overwhelmed. They say much more information is needed on how the coronavirus is transmitted. The new data will fuel debate about the setting in which the lock will be lifted first, for example, whether it is relatively safe to host outdoor events.

And last week, several groups launched studies aimed at providing answers. These include projects to analyze how virus-laden aerosols behave in the air in an attempt to understand how the disease is transmitted between humans. In addition, other schemes will focus on healthcare workers to investigate how the virus is being transmitted to patients and then to others.

The importance of this latter approach was revealed in recent figures for Covid-19 cases that have shown a decrease in the number of new cases in hospitals but reveal significant increases among health and social care workers.

This point was emphasized by epidemiologist Anne Johnson of University College London. She said cutting off Covid-19 transmissions to health and welfare workers had become a top priority. “Half of all new infections reported last week were among healthcare workers,” he told the Observer. “This has become the forefront of the spread of the disease.”

Lack of protective equipment and clothing may have worsened the situation, he added. “What is certain, however, is that care workers are still at risk from their patients, from whom they can contract the virus and, in turn, pass it on to colleagues, their own families, and possibly others. We must focus on limiting the spread of Covid-19 among healthcare and healthcare workers as an absolute priority if we are to have a chance to stop this epidemic. “

This view was endorsed by infectious disease expert Tom Wingfield of the Liverpool School of Tropical Medicine. “The numbers show that the rate of decline in new cases is slower in the UK than in other European countries and that it is likely due to transmission that occurs in health and social care settings, transmission in the community despite social distancing and, to a lesser extent to a certain extent, the chains of transmission that are still occurring within households, especially in larger households or shared accommodation. “

A healthcare worker with gloves and an apron
Half of all new infections reported last week were among healthcare workers. Photography: Murdo MacLeod / The Guardian

Last week, researchers at the University of Bristol launched a major study aimed at precisely discovering how health workers are being infected by the Covid-19 virus. “We have taken a group of 130 healthcare workers and are going to evaluate them intensively over the next three months,” said Professor Adam Finn, the project leader.

“We will take samples of them twice a week, we will take blood samples regularly and we will catalog their symptoms, with the expectation that some of them will become infected. Then we can know when they became infected; how does that relate to your symptoms at the time; and how it relates to your immune response. We are going to discover details of the natural history of the disease because none of this information is known in detail. On the other hand, it is vitally important if we want to understand how this disease behaves. “

Finn said the current model of the disease, while excellent, was based on assumptions. “Essentially, the models are guesswork about the behavior of the virus. To get rid of the guesswork, we must provide evidence on how the virus really behaves. “

Another group at the University of Bristol is taking a different approach, led by the chemist, Professor Jonathan Reid. His team is studying how the Covid-19 virus is transmitted from one person to another. This happens when infected people expel or sneeze quite large drops. However, it is also possible that viruses are spread by much smaller aerosol particles, although it is not clear whether they can carry enough viruses to be infectious.

“It is clearly important to find out because aerosols can travel much further than heavier droplets,” said Reid. His team has just built an automated high containment laboratory that contains a device in which clouds of virus-laden aerosol particles can be suspended while researchers alter temperature, humidity, ozone, sunlight levels, and other variables. .

“In this way we can study how the infectivity of the virus changes,” Reid added. “That could tell us if it is affected by heat. If so, there could be some seasonality in this epidemic. We could also have a better idea of ​​how to operate air conditioning in hospitals, residences and public spaces, in terms of temperature or humidity, to reduce the life of the virus and thus reduce its exposure. ”

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