COVID-19
A guide towards healthy classrooms
How can we reduce the potential spread of the SARS-CoV-2 virus through aerosol transmission in classrooms? Researchers from Europe’s COST-Action INDAIRPOLLNET (led by Xavier Querol and Maricruz Minguillón from CSIC and Michael Riediker from SCOEH) developed a guide...
This winter, be quiet when going to ski
Winter has arrived and so did a second wave of the Corona-disease. With winter comes also snow and the desire to go skiing. But is it safe? The debates are heated and governments take actions that go from asking people to mask up to prohibiting skiing all-together. But what does science tell us? Let’s look at some of the strategies.
Corona strategies inspired by a battle-field game
I was recently contacted by a soldier who was trying to understand why the virus continues to spread rapidly even though my research suggests that those having the possibility to transmit the virus to others are rare. I answered with a battle-field analogy. These are...
A tool to rapidly simulate the airborne virus exposure in different indoor scenarios
We estimated the variability of the viral emission strength in the general infected population when breathing, speaking softly and loudly. Thus, how often we have to expect that an infected person has low, medium or high virus emissions.
We then packaged all the complicated statistics into an easy to use tool that allows experts a rapid simulation of a wide range of indoor scenarios. Here you can read more about it and download the tool (an Excel-Spreadsheet).
How can we stay safe in fall and winter? Part 2: collective measures
In my last blog I talked about individual measures that each and everyone can take to stay safe and healthy. Here I will touch on collective measures. Collective measures are those that need to be done together to protect everybody or a specific group of people, such as the elderly and sick. Typically collective measures need the definition of rules within a larger collective, such as a company or by a government.
How can we stay safe in fall and winter? Part 1: individual measures
The seasons are changing and the corona-virus is still here. In many parts of the world, a second wave has started. How can we stay safe and healthy during the coming fall and winter? Do we need a second lockdown? Not, if we take the right measures - and - importantly...
Only few emit sufficient virus to be infectious via aerosols – but this is still bad news!
We published a model to estimate viral aerosol emissions from simulated individuals with asymptomatic to moderate COVID-19. People in the same room as a super-emitter are likely to get infected. Aerosol super-emission of viruses is a rare phenomenon but still a big public health problem. Ventilation helps, but measuring CO2 in the room is not giving the information we need.
Nano-safety research lessons for dealing with aerosol transmissions of COVID-19
Viruses have many properties that are well known to nanomaterial researchers because once released from a host cell, they correspond to a large part to nanovesicles dispersed in an aqueous salt and protein solution. Many of the strategies developed for safe work with high-activity nanomaterials can be expected to work also for the virus…
Low exhaled breath droplet formation may explain why children are poor SARS-CoV-2 transmitters
A characteristic of the novel coronavirus disease 2019 (COVID-19) is the few cases of severely affected children. They not only rarely get symptoms but also seem to be poor transmitters. We propose that this may be explained by …
Some of the virus can become airborne. Do I have to worry?
When people breathe, speak or sing, they always emit small quantities of tiny lung lining fluid droplets, small enough to stay airborne for many hours. Should I worry about these aerosols? Not much if you cross others briefly on the street. Yes, if you spend a long...
How to contain COVID-19 when restarting school
Worldwide, countries closed their schools because of COVID-19. But in Switzerland, in three weeks from now, schools are supposed to reopen. Can this be done safely? Probably yes, but only with great prudence! It is not enough to hope that the kids will be fine....
Why location data is important – and how this could be done without invading privacy
Imagine you are driving and hear on the radio: „Attention, in Canton Zurich, there is a wrong-way driver on the highway - to respect the driver’s privacy, we cannot disclose the location“. This would be crazy, right? In public health, location data can be extremely...
Also your cat and dog should go in social isolation
Today, many news outlets reported that one of the Bronx zoo tigers was tested positive for COVID-19. The tigress Nadia developed a severe dry cough, reason why she got tested. It turned out that also the other three tigers along with three lions developed the same...
Shall masks be worn? Yes, but it depends!
True or false? „Washing hands is useless because people don’t do it right and because they touch their face too often!“ FALSE! But why do we hear the same arguments about wearing hygiene mask (surgical masks) to prevent the spread of the respiratory disease COVID-19?...
Crisis management thinks ahead. It is time to develop scenarios for the steps to come!
Imagine you are a pilot. Suddenly a flock of geese hits your flaps, your engine turns off and your plane goes into a steep dive. Will you just try to flatten the curve? No. You must simultaneously regain control over your trajectory, assess what systems still work,...
How simple masks can protect and why it works only if all participate
Have I lost my mind when I say that mandating everybody to wear hygiene masks could help reduce the spread of COVID-19? No. What I propose is to use hygiene masks as an emission control device. Let me explain the concept for adressing COVID-19 with a simple model.
At risk people should stay at home – let them do this as closed social groups!
Those at biggest risk of getting seriously ill from the Corona-virus are asked to stay at home and to go into total social isolation. However, being isolated and alone is a serious burden for their psychological and social well being. We have to find ways to overcome...
Masks are key to resume a mostly normal life
COVID-19 is a very dangerous disease. Can we lock up everybody to prevent the spread? Yes, we can – or almost. An effective strategy that allows most of us to return to a mostly normal life should include wearing masks, washing hands and keeping them clean, and an active programme to produce safety materials.
Washing your hands is not enough, you also need to keep them clean
A couple weeks ago, I was at a public toilet with my two young kids. While we were carefully washing our hands, we saw a strange looking guy heading from his toilet cubicle straight to the door as if he was allergic to water and soap. My kids were shocked and...
What can be done if there are not enough testing kits? Use a smart testing strategy!
In Switzerland, authorities say they test only clear cases because they are afraid to run out of testing kits. But is this the best sampling strategy? Shouldn’t we define a strategy that maximises the information we get from the available tests? In epidemiological...
