COVID in New Mexico

I live in New Mexico, a state that has been ahead of the curve in COVID testing.  We have had some of the best testing from early on during the outbreak, and have now reached the point of having enough tests for anyone who wants one.  Our state posts daily statistics, which I have been closely following and eventually started a spreadsheet on. 

A few comments on what I have observed.

Our number of tests performed has been increasing at an impressive rate.  When I started the spreadsheet (May 9), we had slightly under 100,000 tests done.  The number is now nearing 300,000.  In a population of 2.1 million, that will amount to one test per seven people.  (Although some people may be tested more than once).  In the time I have been keeping track, the number of people being tested has typically risen by something more than 4,000 people per day.  In the meantime, the typical number of positive tests has been rising by around 100 to 150 per day.  On good days, we have had less than 100 positive tests and on bad days more than 150, but I have seen only very few days with increases over 200 and only two with increases over 300.

The effect has been that our rate of positive tests have fallen, even as the number of positives continues to rise at a fairly steady rate.  The rate of positive tests was nearly five percent (4.92%) when I started my spreadsheet and has since fallen below for percent (3.6% today).  The positivity rate in new tests has been noisy, but consistently less than the total positive rate, so the cumulative positive rate continues to fall.

That being said, I do not believe that our increase in testing is uncovering a lot of mild or asymptomatic cases that were going undiagnosed at the beginning.  The reason I think that is that if we were uncovering more mild or asymptomatic cases than before, one would expect the mortality rate or hospitalization rate (as a percentage of infected people) to go down.  Instead, the mortality rate has been holding steady at about 4.5% of infected people and the hospitalization rate has been holding steady at about 17% of infected people.*

The infection rate has been unequal across the state.  Unsurprisingly, Bernalillo County, the county that includes Albuquerque, and by far the most populous county in New Mexico, has counted for a considerable share of the infections, but less than its share of the population.  With approximately 30% of the population of New Mexico, Bernalillo County's share of the total infections has fallen from 23% on May 23 to 17% today.  Positivity rate has fallen from about 3.5% to under three percent.  There does not appear to be any significant increase following the protests, but I am still warily watching.

Dona Ana County is New Mexico's second most populous with about 10% of the population.  Although Dona Ana County originally appeared to be doing well, it had a recent outbreak among its colonias (roughly rural slums).  I am not fully confident that the outbreak is behind us, but at least it does not appear to be running out of control.  The total positive rate in Dona Ana County is now below 3%, with the positive rate among new tests noisy, but rarely above 5%.

Santa Fe County, with a population of about 150,000, has had over 18,000 tests and only 196 positives, for a rate slightly over 1%.  Santa Fe County is doing fine.

The hardest-hit counties in New Mexico have not been its urban areas, but San Juan County (population 124,000) and McKinley County (population 72,000), two counties in the northwest of the state with large Navajo populations.  Both have greater absolute numbers of cases than the much more populous Bernalillo County.  Positive test rates have run as high as 15% in San Juan County and perhaps even 19% in McKinley.  It should also be noted that McKinley County, despite its smaller population, has had more tests done than San Juan County -- the number exceeds 20,000, or about 28% of the population.  There is some sign that the worst may have passed in San Juan County; positivity is noisy but has fallen to single digits for something over a week.  But McKinley County continues to have positive rates in double digits.

Sandoval County also deserves mention.  Home to many Indian Pueblos, it looked alarming early on during the outbreak.  It was showing positive cases far in excess of its population (slightly smaller than Santa Fe County), with a rate of about 7%.  There are now only a handful of new cases per day, and the positive rate fell below 3% for the first time today.  I don't know what the pueblos have done, but it appears to have worked.

The other (mostly rural) counties are doing well.  And, incidentally, not all Native American populations have been hit hard.  Rio Arriba County has the Jicarilla Apaches and Otero County has the Mescalero Apaches and both are doing fine.

Deaths and recoveries are also interesting, although the recovery rate comes with the warning that the number of recoveries may be understated because not everyone who has recovered informs the Health Department.  Recovery rate is useful, because it tells us when the worst is past.  The recovery rate for the state as a whole is currently 44.34%.  For Bernalillo County the rate is 62.88%.  The overall death rate has consistently been around 4.5%.  That rate has not gone down with increased testing, suggesting that increased testing has not uncovered a lot of mild or asymptomatic cases that were being missed. 

San Juan County's mortality rate has been 7%, which seems excessive.  I thought this might be a sign that we were missing cases in that state, but the positivity rate is going down, and the recovery rate is up to 52/4%.  These are signs that the worst may be passed, yet the mortality rate remains high.  McKinley County's death rate is edging up and now exceeds 5%.  Nor is the worst over.  Positivity remains high in new tests, despite extremely widespread testing.  And, worse, only 35.5% of all people diagnosed with the disease are known to have recovered.

Meanwhile, Dona Ana County's mortality rate remains anomalously low, at less than one percent, or six deaths out of 718 total cases.  When the outbreak began there, I waited for a upsurge in deaths, but so far it has not materialized.  And a little over half the people diagnosed in Dona Ana County have now recovered.  This would seem like a hopeful sign, that we have become more effective in treating this disease, except that death rates continue to rise in San Juan and McKinley Counties.

There has definitely been a recent upsurge in cases in New Mexico, focused on a prison in Otero County, though without apparent spread to the general community.  There have been 828 positive tests in a very short period of time.  Only six people have died so far, but only ten have recovered.  Today the prison diagnoses were 30% of total new cases and 15% of all active cases. 

Finally, although 1,746 people have been hospitalized for COVID in New Mexico, there have never been more than 223 active hospitalizations at a time, which is manageable.  The number of active hospitalizations peaked on May 15 and has been steadily declining since June 10.  But I expect an increase soon as a result of the prison outbreak.

Stay tuned.

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*There has been a recent drop in the hospitalization rate to 16.53% of infected people, but i suspect that is because of a recent surge in cases at a prison, with hospitalizations still lagging diagnoses.