Drowning in Coronavirus Research, Part 69

By August 22, 2020 Commentary

A couple of comments on items from readers.  MG tells me his personal experience of deferred care.  He was not able to receive his normal regular physical exam.  By the time he got in, he was diagnosed with cancer.  Fortunately it sounds as though it is being dealt with, but delays in diagnosis are often associated with worse outcomes.

Physician readers have told me that they have patients who go for CV tests, get tired of waiting so they leave before ever being tested.  They then get notices telling them they tested positive!!  Apparently the state is treating anyone who shows up for a test but leaves before the sample is taken as a positive result!!

Finally, a mother writes about the requirement that young children, in this case a 5 year-old, are expected to wear masks in school.  This is horrifying to me and completely unnecessary.  What message are we sending these children?  How can their facial reactions be understood, or those of teachers or classmates.  What health issues are we creating for them.  Just more of the insanity around what we are needlessly doing to children.  Hate to always point to Sweden, but school for young children kept going, no masks or other nonsense and no issues with cases.

Kind of an interesting study that relates to cross-reactivity among families of respiratory viruses.  (Infl. Article)  The authors examined whether infection with earlier waves of H1N1 flu virus strains offered protective immune responses against the severe 2009 swine flu H1N1 epidemic.  Older individuals experienced less infection and less severe illness due to these earlier infections that created adaptive immunity.

And one note on the coronavirus briefing by Minnesota officials yesterday.  A question was asked about the effect of the mask mandate.  And again we got the answer about it being hard to pin down the effect of any one intervention, cases have stabilized, maybe would have grown without the mandate, but there is no precise way to differentiate effect of masks, etc.  A very, very different explanation that the one we got when the mandate was put in place, which was that this single step would stop the epidemic dead in its tracks, just like it has elsewhere.  Oh wait, that actually hasn’t happened anywhere.

Another study that bears on mask effectiveness.  (JAMA Article)  This one is in the context of what is an acceptable alternative for health care workers if they run out of N95 masks.  The standard is 95% filtration of certain sized particles.  The researchers found that expired and reused and sterilized N95 masks still met the standard.  Wrong sized N95 masks did not.  Surgical masks with ties were well below the standard and ones with ear loops were far below the standard.  The last mask type is commonly used by people in the community.  The tests were conducted on people doing normal activities like speaking, nodding, turning their heads, etc.

The seasonal variability of coronavirus infections is unclear.  Here is another study looking specifically at the impact of temperature.  (Medrxiv Paper)  The researchers compared temperatures and case rates in 50 countries in the Northern Hemisphere from January 22 to April 6.  Daily minimum temperature and dew point were collected on a daily basis.   They found a significant effect in which a decrease in temperature led to more cases and an increase in temperature to fewer.  The effect of humidity, as measured by dewpoint, seems to be correlated with the effect of temperature.  Hard to explain the case surges in the southern US if it is solely temperature that creates the seasonal effect.

Couple of modeling-related studies.  This one again cautions about the need to recognize variation in susceptibility, with a focus on the mathematics showing that failure to do that produces model results that greatly over-estimate the effect of an epidemic.  (Arxiv Paper)  We are familiar with that concept in Minnesota.

The second paper deals with the effects of “super-spreaders”; those persons who are highly infectious and have lots of contacts.  (Arxiv Paper)   This is another variation on the theme of heterogeneity in susceptibility and infectiousness.  The authors’ analysis also suggests that modeling incorporating these concepts is more consistent with the course of this epidemic.

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