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    • Apr 23, 2020
    • 6 min read

Pretty Light Knowledge

After more than a 100 days into the new reality of life with the coronavirus, we still don’t understand many aspects of the problem. What’s concerning is that experts working in the field also belong to the “we” category, as they also don’t have enough information to fully understand SARS-CoV-2, at least not at the moment. As far as coronavirus knowledge goes, we are at the early stages of collecting data, running preliminary analyses, and trying to get a better general understanding of how SARS-CoV-2 works. We are still in the position of only being able to make cautious suggestions and offer preliminary hypotheses rather than being able to definitively answer questions. Questions that we all want answered. In this post we are going to summarize our knowledge for some of these questions.


" As far as coronavirus knowledge goes, we are at the early stages of collecting data, running preliminary analyses, and trying to get a better general understanding of how SARS-CoV-2 works."
 

Things we don’t know or are not sure about

Transmission method It is well established that SARS-CoV-2 is transmitted between humans via the “droplet infection” method. But are there other ways how people can get infected? This is where the uncertainty kicks in. Scientists can’t say for sure that SARS-CoV-2 isn’t transmitted through other methods. There are no reported cases of smear infections from contaminated surfaces (as of April 20, 2020). However, it is theoretically possible that viral particles located on the hands may find their way to the mucus tissues of the nose, eyes, or mouth, where they may lead to an infection. Due to the relatively low stability of the coronaviruses, smear infections are only likely to happen shortly after contamination. But it is possible. SARS-CoV-2 survival on different surfaces In general, coronaviruses that infect humans are not very stable on dry surfaces. However, studies on SARS and MERS indicate that these viruses can survive on a range of surfaces including glass, metal, or plastic for up to nine days. They also appear to be more resistant under low temperature and high humidity conditions. Experts believe that the results obtained from these coronaviruses are transferable to SARS-CoV-2. Researchers from the US National Institutes of Health (NIH) at Rocky Mountain Laboratories in Hamilton, Montana recently published a study in which they tracked how long SARS-CoV-2 can survive on different surfaces. According to their results, the virus remains active in aerosols (droplets coughed out into the air) for up to three hours. It can survive for longer periods of time on cardboard (up to 24 hours) and even longer on steel and plastic (up to 2-3 days). All this suggests that even though there are no recorded cases of infections caused by a contact with a contaminated surface, it is not out of the question. We clearly need more experiments and additional data on this subject.

Data from van Doremalen et al., 2020


When will the pandemic end? Predicted dates for the end of this pandemic keep being pushed back. At the beginning - or should we say when we finally started taking the situation seriously - we heard politicians mention mid April as the time when the situation would start improving (which clearly was not realistic). Then the dates shifted to early May, and now we are talking about mid May or June. It does not seem like we have the ability to confidently predict when the situation is going to stabilize. But we do know what indicators we are looking for. We're looking for a steep and consistent decrease in numbers of new cases every day. Only then can we start thinking about cancelling restrictions. For example, in New York City numbers have started to stagnate and finally go down after a few weeks of consistent growth. However, the authorities have not rushed to raise restrictions and ask the public to keep following the guidelines. Only after a few weeks of consistent decreases measures may be taken to loosen some of the restrictions.

Data from https://www1.nyc.gov/, downloaded on April 22, 2020. Information collected by the NYC Health Department

The New York City pattern looks promising but this is still not the case for many places in the USA and countries around the globe. The figure below demonstrates that in some of the countries, the number of daily new cases is on the rise. There may be different reasons for that: (i) the virus reached these countries later, (ii) appropriate testing hasn’t been put in place initially so we don’t have data for the earlier period, (iii) the restrictions measures have not been enforced at the same time as in other countries.


Data from https://www.worldometers.info and https://ourworldindata.org

 

What we do know, sort of


Restriction guidelines are effective. As a society, we have made a number of mistakes in how we handled the virus situation, and we still don’t know much about it. However, the effectiveness of the restriction guidelines is one of the things that there are no doubts about. We know for a fact that social distancing, confinement, and self isolation definitely work and help tremendously to fight the pandemic. One of the main reasons why the number of infected people has started to decrease in certain areas is because strict regulations have been implemented, and more importantly that people have followed them. We also know that time is crucial, the sooner the actions are taken, the better. Implementing and following social distancing guidelines literally save lives. Since we are still missing a lot of essential information about the virus, we can’t say for certain which precautions are necessary and which ones are not strictly obligatory but still advisable. Overall, it seems like being extra careful - probably more so than feels appropriate - would not hurt. Soap helps The most important and effective precaution that we may take is to often wash hands with soap. Our hands always have some natural oils on them, and viruses can stick to the oil molecules via an electrostatic charge. Surface active agents present in most soaps and other household detergents, e.g. dishwater detergents can dissolve fats, damage the virus surface making it inactive, and help physically wash away viral particles from the hands. This is why surgeons pay so much attention to meticulously washing their hands before performing a surgery. Alcohol-based disinfectants and sanitizers are also effective and should be used when soap is not available.




SARS-CoV-2 temperature range resistance Some preliminary data are available regarding the SARS-CoV-2 resistance to different temperatures. Studies performed on coronaviruses similar to SARS-CoV-2 indicate that they are resistant to low temperatures. Both SARS and MERS can survive for long periods of time at +4C and even at -20C. Under certain conditions viruses can also survive at -80°C. It means that simply placing contaminated products to conventional refrigerators and freezers won’t kill the virus. The good news is that coronaviruses appear to be thermolabile, i.e. sensitive to heat. Preliminary results demonstrate that the incubation temperature of 70°C deactivates the SARS-CoV-2 within 5 mins. Therefore, as a general rule, cooking food at higher temperatures is a safer option compared to consuming raw or undercooked products.


" It is not likely that after the official restrictions are lifted, we will be back to our pre-corona lives like we remember them."
 

Life after the pandemic


After we can safely say that the worst is behind us and when we start piecing society back together, it’s going to happen gradually, not all at once. It is not likely that after the official restrictions are lifted, we will be back to our pre-corona lives like we remember them. Bars, restaurants, and coffee shops will not be working at full capacity. If your favorite restaurant could normally sit 50 people, after it reopens it will probably be able to host only 10 or 20. We will be able to travel but not like we used to. If last year it was technically possible to travel virtually anywhere in the world at any given time, the rules will likely be different after the pandemic is over. At least at first. Obviously, these are only minor inconveniences compared to the grand scheme of things. For the moment we need to focus on how to get there, to the post-corona realm. We at Pretty Light Science are committed to washing our hands as often as needed and staying away from other people for as long as required.

 

Glossary


Droplet infection - passing of a pathogen through small, wet particles that stay in the air after coughing, sneezing, or talking.

Smear infection - passing of a pathogen by direct contact with an infected person (direct contact infection) or indirectly by touching contaminated surfaces (indirect contact infection).

 

Works Cited

van Doremalen, N., Bushmaker, T., Morris, D.H., Holbrook, M.G., Gamble, A., Williamson, B.N., Tamin, A., Harcourt, J.L., Thornburg, N.J., Gerber, S.I. and Lloyd-Smith, J.O., 2020. Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1. New England Journal of Medicine.


Günter Kampf, Daniel Todt, Stephanie Pfaender, Eike Steinmann: 'Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents', in: Journal of Hospital infection, 2020, DOI: 10.1016/j.jhin.2020.01.022


Chin, A., Chu, J., Perera, M., Hui, K., Yen, H.L., Chan, M., Peiris, M. and Poon, L., 2020. Stability of SARS-CoV-2 in different environmental conditions. medRxiv.





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