Wednesday, March 18, 2020

Updates on Coronavirus in New Mexico:  March 18
An Argument for Mass Testing for Coronavirus
Why Mass Testing Might be Needed for the Paso del Norte Border Region

Prof. Luigi Zingales is Robert C. McCormack Distinguished Service Professor of Entrepreneurship and Finance, and Charles M. Harper Faculty Fellow at the University of Chicago.  He is not a health care expert, but has studied extensively in Italy, where he grew up.  He posted this in the ProMarket blog this morning (click here).  I can't comment on the reliability of his post, but, if true, it is relevant to t how our health care system responds to the current coronavirus crisis, and particularly here on the US-Mexico border.  Readers might also want to review various statements made recently by experts about the importance of asymptomatic spread of the virus in an article by Elizabeth Cohen for CNN (click here).  It tends to confirm Zingales' argument.
According to Zingales more than 50 percent of COVID-19 cases on the Diamond Princess cruise ship and in Vo'Euganeo, a small town near Padua, Italy, were asymptomatic.  If true, not only in those two limited cases, but here today in the US, the statistic has far-reaching and urgent implications for how the public health system should respond to the coronavirus crisis.

If a large proportion of coronavirus cases are asymptomatic, and if health officials are testing only those with symptoms, then there are a lot of persons walking around believing they are fine but spreading the disease.  And the evidence appears to be strong that asymptomatic persons can spread the disease (see the CNN article above).

Zingales asserts that in Vo'Euganeo by order of the Governor of Veneto all 3341 persons were tested for coronavirus after the first death occurred, persons who tested positive were isolated.  A two-week lockdown was ordered for the entire village.  Before the lockdown 3 percent of the town was infected.  After the lockdown all persons were tested again and only 0.25% were infected.  Once these few infected people were isolated, the town reopened and has experienced no new cases.

By contrast, on the Diamond Princess, one passenger who had symptoms was tested, and was quarantined.  After that passengers and crew were tested only after showing symptoms, and only after testing positive were they taken off the boat.  Only toward the end did authorities test all passengers.  What had started with one passenger infected, ended up with 20% of the people on board.

In one case, argues Zingales, we go from 3% for none; in the other case we go from 1 person to a 20 percent infection rate, with mass testing being the major difference.

Again, Zingales is not an epidemiologist nor an expert on health care, but the CNN article seems to confirm from true experts that asymptomatic persons can spread the virus.

Paso del Norte

President Trump today agreed with Canada to close the border to people, but not to commerce.  He may do the same with Mexico.  But if a even a small proportion of the population (say, 1%) has the virus but, of these, a significant proportion (say, 35%) is asymptomatic and therefore not tested, we are likely to have a rapid regional spread across the borders, probably in both directions, even with a closing of the border to all but truck traffic.  There may be more going on than I know about, but so far the evidence suggests that both Juarez and El Paso and Las Cruces have been testing only people with symptoms and possibly only high-risk persons with symptoms.  If the rate of infection from non-symptomatic persons is significant, we should be testing massively in this region to begin to understand the true dimensions of the spread of the disease.  This understanding would have serious implications about the kinds of policies needed to stem the disease and take care of those who are hit more severely with pneumonia and other complications.  And we don't have a lot of time, since the virus spreads very rapidly.

Regional, cross-border cooperation could help in understanding the true dimensions of the disease.  So far there is no indication that cooperation is taking place.

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