Physics Questions About the Spread of Viruses

Physics Questions About the Spread of Viruses

I haven’t investigated these questions, but I also don’t yet see definitive answers about them with the new COVID-19 virus.  I was a physicist, but only on a nuclear scale, 10^5 times smaller than an atom.  I am also not a biologist or medical doctor.  But I do see aspects of problems that are Physics.

First, there are questions about the drops from sneezes and coughs and their spread.  This is unfortunately summarized as keeping a safe six foot distance.  Associated with those are the effectiveness of various masks, in either direction, and possible transmission from the mask’s non-hygienic disposals.  These also involve air conditioning systems and filters.  There is also the question whether droplets can be visualized in real time with ultraviolet or infrared light, or at least in special lab conditions.  The range of droplets probably depends on their size, is a statistical distribution, and would be dependent on ambient airflow.

Next are the surface survivability questions.  These should distinguish between types of surfaces.  Even if there are surfaces which can secure viruses, or kill them.  Associated is the effectiveness of various sprays and the size and their droplets and frequency that are needed.  So far, there are no publicized tests on COVID-19, but a literature survey of other viruses showed survival times of from 15 minutes to 9 days.  So the news reported that the COVID-19 could last 9 days.  Clearly it depends on the surface, on the temperature, on the humidity, on the airflow, on the droplet size, and probably on the origin of droplets, and the development stage and seriousness of the infection in a particular patient.

Then there are the questions of human interaction rules.  The prime example is the question whether the crew of the Diamond Princess, who were not quarantined, could have spread the virus in the preparation or distribution of food.  There is also the question why everyone on board wasn’t tested, even before they showed symptoms, which could take five days to appear.  However, the supposedly sure safety interval for quarantine seems to be set at 14 days.  This has to be tested, also.  There has to be a time distribution, and the quarantines may show what this actually is for this specific coronavirus.

Time is of the essence in many of these questions, both in that the answers are probability distributions over time, and that finding timely answers can allow for effective intervention and prevention.

Presumably, many labs have the capabilities of finding these answers.  There are also many infected patients in many countries for samples.  As the viruses mutate, the questions have to be  answered again.

Clearly, personal vaccinations would be the best answer, since they protect the individual themselves, under any external assaults.  Actually, vaccines may not be fully active for prevention, but they can sometimes reduce the impact of the infection.  The other problem is again time:  they take time to develop and test, and then they take a large part of a year to produce.  Even after that, the more seriously spreading viral strain may not be the initial one protected against.  So all of the above prevention knowledge is still very important.

I also still have biomedical questions that I haven’t seen covered in the press.  Is the pneumonia that the most serious cases suffer unique to the COVID-19 virus, or is it one of the three standard ones covered by the two pneumonia vaccines?  Are people who were covered by the pneumonia vaccines less susceptible to serious complications?  What are the differences in seriousness between smokers and non-smokers?  Do even recovered patients still have lung or liver damage that would show up in an MRI or other tests?  We seem to have few studies from the outbreak in China, which may be due to the fact that they are overwhelmed by the size and speed of the outbreak.  The number of new cases now seems to balance the number of recoveries.

A study of China’s coal burning and other fossil fuels has shown that greenhouse gas emissions have been reduced about 25% during the virus outbreak.  Another question is how the smoggy and asthma inducing air in big cities can increase the severity of reaction to viruses.

About Dennis SILVERMAN

I am a retired Professor of Physics and Astronomy at U C Irvine. For a decade I have been active in learning about energy and the environment, and in lecturing and attending classes at the Osher Lifelong Learning Institute (OLLI) at UC Irvine.
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