English: Note The dangers of COVID-19 aerosols are vastly underestimated

A group of 239 researchers has called for an update of COVID-19 guidelines, as transmission via ultra-fine suspended matter in the air was not sufficiently taken into account. Now the WHO also sees the danger. While many European countries are pressing for a return to normality as quickly as possible – at least that's the way it seems – after the corona crisis has been overcome, 239 researchers from various disciplines are sounding the alarm in the The Journal of Clinical Infectious Diseases."

See: https://academic.oup.com/cid/article/doi/10.1093/cid/ciaa939/5867798]

*Pending danger in enclosed spaces:

Aerosols are the smallest suspended particles and droplets in the air, which are smaller than five micrometers. When breathing out, speaking, laughing or singing, this fine mist spreads throughout the room. The larger droplets quickly fall to the ground, but the finest particles can remain suspended in the air for hours - especially in closed rooms. If an infected person stays in such a closed room, he can infect many others in a very short time - without no direct contact with them.

*WHO reconsiders its position:

In response to the public appeal, the World Health Organization is now also ready to change course. Until now, the WHO had mainly assumed droplet infection was the main culprit of the disease's spread. The WHO now also recognizes "emerging evidence" for the airborne spread of the novel coronavirus, said Maria Van Kerkhove, technical manager for the COVID-19 pandemic at the WHO, in a press briefing. On the basis of the new assessment, the next step would be to adapt the WHO corona guidelines accordingly. A month ago, the WHO had already had to revise its assessment of protective masks.

Aerosols as the most important transmission path:

According to the researchers, investigations on influenza and also on the coronavirus MERS-CoV showed that the viruses spread mainly via aerosols. "We have every reason to believe that SARS-CoV-2 behaves in a similar way and that aerosols are a decisive transmission pathway," said the appeal, which was signed mainly by experts from the fields of chemistry, physics and engineering sciences, but less so by virologists and physicians. The current protective measures - washing hands, wearing a mask, keeping your distance - are primarily aimed at a possible droplet and smear infection. But these alone are not enough. The researchers argue that there has been insufficient evidence of aerosol transmission to date.

*Regular airing helps:

Therefore, the authors of the appeal call for regular and effective room ventilation with fresh air from outside. Air circulation indoors, such as using fans or air conditioning, should be avoided - especially in public buildings, schools, workplaces, hospitals, and retirement homes. Existing ventilation systems should be expanded to include extraction and air filtration systems and/or germicidal, ultraviolet light. Above all, overcrowded rooms and crowds of people in closed rooms should be avoided, not only in bars or clubs, but also in public buildings and transport.

*Indicators show need for reassessment:

A sudden increase of corona cases after bar or restaurant visits, as well as after choir performances, show that the infections were probably transmitted by aerosols in the indoor air, according to Prof. Dr. Clemens Wendtner,head physician of the Infectiology and Tropical Medicine Department of the Munich Schwabing Clinic, who was not involved in the appeal. It is also possible that the ventilation systems that "repeatedly circulated, unfiltered cold air" in slaughterhouses led to the frequent occurrence of corona infections, according to Wendtner. The physician considers the ventilation measures proposed in the appeal to be sensible and had suggested a change of course from the WHO. "In view of the still increasing global infection figures and the simultaneous implementation of relaxation measures in some countries, a WHO call for protection against aerosols containing SARS-CoV-2 would be desirable and, from a scientific point of view, urgently required," said Prof. Dr. Wendtner.

*Adapting behavior to new findings:

At the beginning of the pandemic, transmission via surfaces was "probably somewhat overestimated," according to Dr. Isabella Eckerle,Professor of Infectious Diseases at the University of Geneva, who was not involved in the appeal. On the other hand, the transmission via indoor air due to the proximity to sick people (family celebrations, choir rehearsal, and fitness studios, etc.) has been somewhat under-estimated. "I think the previous very strict distinction between either aerosols or droplet infection is not sufficient to cover all transmission scenarios.” The coronavirus is not a classical aerosol-transmitted pathogen, such as measles or chickenpox, said Eckerle. "A similar scenario is not likely to occur with SARS-CoV-2.”

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Special masks for all are also not a solution:

Although professional FFP3 filter masks could prevent aerosol infection, Eckerle believes that a recommendation for this type of mask in the general population is neither "reasonable" nor "feasible".

"I believe that we must be pragmatic and translate the knowledge we currently have about the pathogen into meaningful, actionable recommendations. Accordingly, super spreading events in enclosed spaces should be prevented,” says the professor of infectious diseases at the University of Geneva.

*Coronavirus pandemic: Is the second wave already here?

COVID-19 caught us all unprepared. Despite some countries' initial successes in curbing the pandemic, the virus is now spreading like never before. Virologists were already predicting a second [and even a third, wave] of coronavirus infections months ago. The more people break the rules of conduct and restrictions introduced to curb the pandemic, the greater the risk of such a second wave. Now, it seems to be rolling in. In many countries, lockdown restrictions are no longer being as strictly enforced. Germany, Spain and Greece were among the first countries in Europe to ease such measures. The World Health Organization (WHO) has warned that the coronavirus may never fully disappear. It has stressed the possible consequences if people take the coronavirus lightly and revert to behavior patterns that prevailed before lockdown measures were put in place. n many countries, shops have reopened, as have restaurants. In Australia,the government has tightened restrictions again after several cases of infection among guests in pubs and bars. People's desire to travel is also on the rise once more - another reason for increased infection rates. Too many people are congregating in too small spaces; parties are taking place again. The risk of infection is rising, worldwide. In Germany, there was a sharp uptick in the number of infections at the end of July. The reproduction rate R also went up again.

*The reproduction number R:

The reproduction rate indicates how many other people one ill person infects on average. This number helps health authorities to better predict infection patterns. For example, if R is 3, it means that one infected person will infect three more people. If the reproduction number is 1, the infection rate remains about the same. In Germany, this reproduction number rose to above 1 at the end of July. This could be due, among other things, to holidaymakers who once again blithely mingled in large crowds even though the pandemic is far from over. If the infection numbers go down, it is an initial success. However, if things go the other way and the reproduction rate increases, this could indicate a second wave of infections. The United States and Brazil have recently experienced the most dramatic increases, followed by India and South Africa. In Brazil alone, well over 8 million people have already become infected with the virus. According to the Brazilian Ministry of Health, more than 3,600,000 people were infected by the end of July.

*The second wave:

There is no uniform international standard for how a second wave is defined. Even the WHO has no clear guidelines. WHO spokesman Christian Lindmeier wrote in an email to DW: "The term refers [only] to new outbreaks that have occurred after an initial decline. The same applies to a 'third' wave." At the beginning of the pandemic, virologists were already warning against a further wave of infection and appealed to the population not to see falling infection numbers as a license to act carelessly. Scientists are comparing the coronavirus with the Spanish flu, which ranged from 1918 to 1920. According to the WHO, it claimed between 20 and 50 million lives worldwide.

*The Spanish flu of 1918 killed millions of people:

That pandemic ran in three waves. The second wave was much worse than the first and caused many more deaths. Between the individual phases, the virus mutated several times and this was difficult to track. And plan for. That very well also could be the case with this current novel coronavirus.

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And what if the virus mutates?

Every virus can mutate, i.e.change. At best, a virus becomes weaker through mutation. This means that it is less dangerous and claims fewer victims. For this to happen, however, a large number of people must already have developed immunity to a virus. Whether this is the case with SARS-CoV-2, researchers do not yet know. People develop immunity against most viruses. When infected, the body produces antibodies and, if these succeed in fighting off the virus, a person becomes immune. The virus can then no longer harm that person. But it is unclear whether this is also completely true of the novel coronavirus. More and more cases indicate that some COVID-19 sufferers no longer have any detectable antibodies in them after just a few months. This could mean that they could become infected again. With a serological test, experts can determine whether someone has produced antibodies against the virus. But such a test does not provide any information about whether the person is then immune to the virus and, if so, for how long. Scientists are now trying to answer these questions.

*So here are the top five reasons why you should consider wearing a mask:

A slew of new studies confirm the effectiveness of face coverings against the coronavirus. The plea from health experts for the public to wear face masks has intensified in recent weeks, as coronavirus cases continue to climb in many areas of the U.S. And a lot of it has to do with what researchers are learning about the effectiveness of face coverings. A growing number of studies point to the mask as a powerful tool that can help control the spread of the coronavirus, which so far has infected more than 9.6 million Americans. Here are five reasons to wear a mask, based on the latest research.

1. Masks protect other people

The primary way the coronavirus spreads is from person to person by respiratory droplets produced when an infected person coughs, sneezes or talks. Face masks, however, can block these droplets. They act as a barrier to keep virus-containing particles from escaping an infected individual and landing on another person, explains Ron Waldman, M.D., professor of global health at the George Washington University (GWU) Milken Institute School of Public Health. A new simulation from researchers at Florida Atlantic University illustrates just how effective face coverings can be in reducing the number of droplets that are dispersed into the air and the distance they travel. Without a mask, droplets traveled more than 8’. A bandanna cut the distance to 3’ 7”, and a folded cotton handkerchief reduced that distance even more, to 1’ 3”, the researchers note. "There's no question; it's indisputable that wearing even a cloth face covering cuts down substantially on the amount of virus that's shared by an individual,” Waldman says.

2. You may not realize you are contagious

It used to be that masks were recommended only for people who knew they had COVID-19, as a way to protect others around them. When it became apparent, however, that the virus can be transmitted by people before they start showing symptoms (pre-symptomatic) and by people who never develop symptoms (asymptomatic), the Centers for Disease Control and Prevention (CDC) broadened its guidelines, urging everyone to wear a cloth face covering in public. Some studies, including a paper recently published in the journal Nature, have found that over 40 percent of people with coronavirus infections never develop symptoms of COVID-19.

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 This makes it extremely difficult to detect who is a potential transmitter of virus, Waldman says. That is why wearing a mask, even if you believe you are healthy, is recommended both by the CDC and the World Health Organization (WHO). It's one way to help prevent unknowingly spreading the virus to others, especially those who are more likely to become severely ill if infected by the coronavirus. "It's a sense of social responsibility,” says Neysa Ernst, R.N., a nurse manager of the Biocontainment Unit at the Johns Hopkins Hospital in Baltimore. You wear a mask because you “want to protect society,” she adds.

3. Masks can protect you, as well

A few studies suggest cloth face masks offer some protection for the wearer, but the protective perks are most obvious when everyone covers the mouth and nose. Think of it as a collective benefit: The more people who block the transmission of the virus with face coverings, the less virus there is circulating in the community. This reduces everyone's risk for infection. Thus, "If that chain is cut anywhere, then the virus is no longer able to propagate or to be transmitted,” Waldman says. “So whether you intervene on the side of the transmitter or the side of the receiver of viral transmission, if you can block the passage of the virus on either end of that chain, then everyone benefits from that.” A few studies highlight the power of widespread community use of face coverings. A report published in Health Affairs, for example, found that states with face mask mandates had a greater decline in daily COVID-19 growth rates compared with states that did not issue mandates. The authors estimate that these mask policies may have prevented as many as 450,000 coronavirus cases in the U.S. What's more, the Institute for Health Metrics and Evaluation at the University of Washington predicts face masks could save as many as 34,000 lives in the next few months. The institute currently forecasts that 180,000 people in the U.S. will die from the coronavirus by Oct. 1. But if at least 95 percent of people wear masks in public, that number will drop to about 146,000. "Beyond a doubt, [face masks] play an important role in reducing transmission,” Waldman says.

4. Masks may help the economy recover

Masks could offer an economic boon, as well. A report released by investment firm Goldman Sachs found that a national face mask mandate could serve as a substitute for lockdowns “that would otherwise subtract nearly 5% from GDP [gross domestic product].” Recent spikes in coronavirus cases have caused some U.S. communities to pause or roll back reopening plans and “have raised fears that we may need to go back to the lockdowns that we saw back in March and April,” Jan Hatzius, head of Goldman Sachs Research and the firm's chief economist, explained in a video briefing on the report. “We know that's very economically damaging.” Lockdowns at the start of the outbreak brought the U.S. economy to a halt; more than 44 million Americans have filed for unemployment benefits since mid-March. The widespread use of face masks, however, could significantly slow the growth rate of virus cases, which top infectious disease expert Anthony Fauci, M.D., said could hit 100,000 per day if outbreaks are not controlled. And slowing the rate of new cases would “reduce the need for what otherwise would be a significant hit to the economy,” Hatzius said.

5. There are few alternatives

In the absence of a vaccine and more effective drug therapies to treat people who are sick with COVID-19, the preventive measures of handwashing, physical distancing and mask wearing are “the three things that I do know that work” when it comes to fighting the coronavirus, Johns Hopkins’ Ernst says. What's more, these are low-cost strategies that are relatively simple to implement. "The effort is minimal compared to the benefit. It's the cheapest, easiest intervention for the effect that it provides, for the degree of protection that it provides,” GWU's Waldman says. “Just staying 6 feet apart from other people, frequent handwashing and wearing a face covering in public, especially when social distancing is not possible or difficult - if people did those three things, we wouldn't be where we are today.”..

As always, be informed and stay safe!

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