Dr. Gerald’s Latest Epidemiological Analysis for Arizona

Here’s a link to Dr. Gerald’s latest Epi report for Arizona. Below is his introductory paragraph. You can go to the full weekly report at this link.

For the week ending October 25th, 7221 new Covid-19 cases were diagnosed in Arizona (Figure 1). This represents a 19% increase from last week’s revised tally of 6064 cases. Reporting delays continue to be minimal.

Accordingly, last week’s tally of 5779 new cases was only upwardly revised by 5% (285 cases) this week. Some of this backfill was also attributable to moving this report earlier in the week. Case counts continue to increase among all age groups (Figure 2 following page). Rising case counts warrant reappraisal of government policies as well as individuals’ adherence with face masks, physical distancing, and hand hygiene practices. Current transmission levels are just shy of those observed during the first week of June when 8239 cases were diagnosed. A mere 3 weeks later, Arizona’s case count reached a peak of 27796 cases.

Given the possibility of exponential growth, current conditions could deteriorate rapidly.

HHS Approves State Authorized Pharmacy Interns to Administer SARS CoV2 Vaccines

HHS issued guidance this week that will allow state-licensed pharmacists and state-authorized pharmacy interns under their supervision to administer COVID-19 vaccines and tests authorized or licensed by the Food and Drug Administration, subject to certain requirements. The guidance also clarifies that pharmacy interns authorized under earlier guidance to administer vaccines to children need not be licensed or registered with the state board of pharmacy.

FDA Approves remdesivir to Treat COVID-19

The FDA approved a remdesivir medication called “Veklury” to treat COVID-19 in people 12 years and older (and weighing over 88 lbs.).  The medicine is only approved for COVID-19 treatment if it’s administered in a hospital or other acute inpatient care facility.

This is the first medication that has been fully approved for the treatment of COVID-19. Many other medications have been given Emergency Use Authorization for use in patients with COVID-19 but this is the first med to be fully approved for treatment. The drug appears to help some patients recover more quickly but it hasn’t been shown to improve survival chances.

A clinical trial found that it accelerated recovery among patients that had advanced disease. It was a randomized, controlled trial involving 1063 patients.  The study found that patients who got remdesivir recovered 31% faster than the people that got the placebo (p<0.001). The median time to recovery was 11 days for patients treated with remdesivir compared with 15 days for the placebo group.

Here’s one of my previous blog posts that walks you through how the FDA processes work when evaluating and approving medications. Here’s where you can read FDA’s press release on the remdesivir approval.

State Health Department Changes School Metric Recommendations

Was it a good decision?

The main drivers for managing COVID-19 risks in Arizona schools are the mitigation measures that are in place to prevent the spread of the disease in schools. The other important factor is the level of community spread within the district. Both are important factors for school governing boards to use as they make these important decisions.

Earlier this week the ADHS quietly changed the criteria that they recommend school districts use to make decisions about whether to use in-person, hybrid or virtual instruction. Arizona uses three different metrics for the benchmarks: percent positivity, cases per 100,000 and something called COVID-like illnesses reported by hospitals.

The first 2 metrics are solid benchmarks. Both percent positivity and cases per 100,000 are routinely reported across the public health system now- and both rely on firm diagnoses. Covid-like illness, on the other hand, is voluntarily and sporadically reported and largely subjective. It comes through a voluntary system called “Biosense”.

The guidance that was established a few months ago stated that “Schools should start preparing for virtual learning when one or more of the benchmarks are in the substantial spread category”. Under the guidance established this week, the Department now says that “district leaders to move from hybrid to virtual learning if all three benchmarks move to substantial for two weeks”.

The problem with that change from my perspective is that it puts decision-making emphasis on all three indicators even though only 2 of the indicators are solid ones (case rates and percent positivity). Covid-like illness is only a syndromic surveillance indicator that is subjective and sporadically reported. Putting Covid-like illness on par with the others and stating that all 3 indicators need to be in the ‘substantial’ range before going to virtual instruction puts more emphasis than is reasonable for that indicator.

Members of school governing boards may not understand that the Covid-like illness is a flimsy metric and may very well make decisions based on the assumption that it is a good indicator of community spread. It is not.

Take Graham County as an example right now. Both their cases per 100,000 and percent positivity are well within the substantial range and have been for 2 weeks… yet Covid-like illness is firmly in the ‘good’ range. This new guidance could give the impression to Graham County governing board officials that their decision to keep in-person rests on good evidence (the fact that Covid-like illness is still in the ‘good’ range) when in fact that indicator is unreliable.

Perhaps the decision to keep the guidance developed this week will be reviewed after additional scrutiny.

New Report Shows Low Risk of COVID Transmission in Airplanes

Can you trust the results?

Perhaps you heard about a report last week that attempts to demonstrate that jet aircraft are very safe environments with respect to COVID transmission. I went to the new report (conducted by the US Department of Defense & United Airlines) which concludes that there is very low risk of transmission of the SARS CoV2 virus on commercial jet aircraft.

One of the things I check when I’m looking at a study is the professional affiliation of the main authors and the funding source for the study. Not that the author’s institutions and the funding source that paid for the study are the end all and be all of credibility…  but it does help me to think through whether there’s a chance that the investigators may have a conflict of interest that led them to put their hand on the scale. This report was jointly conducted by the DOD and United Airlines. I’ll just leave it at that.

The study occurred onboard United Airlines aircraft. The report states that fast onboard air recirculation, downward designed air ventilation, and efficient HEPA filters “make the cabin of a United airplane one of the safest indoor environments in the world”. Quite a statement indeed!

The investigators used fluorescent aerosol tracers between 1-3 µm (micron) and optical sensors, coupled with DNA-tagged tracers to measure aerosol deposition. They tested planes for 8 days (both inflight and ground tests) on Boeing 777-200 and 767-300 airframes.

Tracer aerosols were released from a simulated infected passenger in multiple rows and seats to determine their risk of exposure and penetration into breathing zones of nearby seats.  Over 300 aerosol release tests were performed, releasing 180M fluorescent tracer particles from the aerosol source (simulated virus aerosol), with 40+ Instantaneous Biological Analyzer and Collector (IBAC) sensors placed in passenger breathing zones for real-time measurement of simulated virus particle penetration.

Their results found that there was a 99.7% reduction of 1 µm simulated virus aerosol from the index source to passengers seated directly next to the source. An average 99.99% reduction was measured for the 40+ breathing zones tested in each section of both airframes.

The authors attribute aerosol reductions to the dilution, mixing and purging of aerosol from the simulated source due to high air exchange rates, downward ventilation design, and HEPA-filtered recirculation.

They concluded that “… transmission model calculations using the measured aerosol breathing zone penetration data indicates an extremely unlikely aerosol exposure risk for a 12-hour flight when using a 4,000 virion/hour shedding rate and 1,000 virion infectious dose”. 

They also conclude that there is “… virtually zero risk of COVID-19 transmission on airplanes when a passenger is seated and wearing a mask, as on average only 0.003% of infected air particles could enter their breathing zone, even when every seat on the plane is occupied”. Alrighty then.

Remember, this is one report, and it’s not published in a peer-reviewed journal. Furthermore, it doesn’t use epidemiological or observational human data or observations. Rather, it is a study that simulates virus aerosols and records the percent reduction of those particles over time. It does not establish whether the SARS CoV2 virus behaves nor what the likelihood is that particles from an infected passenger will infect fellow passengers.

To be honest, when I read the following statement in their executive summary, I had pretty much made up my mind whether I trust these results.

The study occurred onboard United Airlines aircraft found that “… fast onboard air recirculation, downward designed air ventilation, and efficient HEPA filters make the cabin of a United airplane one of the safest indoor environments in the world”. C’mon.

State Submits SARS CoV2 Vaccination Plan

Arizona turned in a draft COVID-19 vaccination plan to the CDC this week. The 51-page plan covers the processes they plan to use to make decisions when the time comes to roll out SARS CoV2 vaccine. The plan includes things like how allocation decisions will be made, how initial priority populations will be identified, logistical decision-making regarding specific requirements for vaccine deployment, and how providers will be recruited and enrolled for the COVID-19 vaccine.

Importantly, the draft version includes county health departments and tribal governments as key decision-makers in the planning and execution of the plan. Local health leaders will be responsible for allocating a vaccine by priority. The priorities will include pharmacies, long-term care facilities, pre-designated clinics or hospital locations, then prioritized target groups, and lastly the general population.

Much of the analysis and recommendations will come out of a state Vaccine and Antiviral Prioritization Advisory Committee (VAPAC) which consists of “… Subject Matter Experts who are responsible for reviewing the CDC, Advisory Committee on Immunization Practices, and National Academies of Sciences, Engineering, and Medicine guidance and providing recommendations to the Department to develop a state vaccine allocation plan.”

The members of the VAPAC committee are listed on the last page of the report (page 49).  As you read the plan, pay particular attention to the importance that is placed on the VAPAC committee recommendations.

The document is important in that it lays out a process for decision making when the vaccines arrive- but it doesn’t provide the detail the likes of which one would see in an Operational Plan.  Once the FDA, CDC, ACIP make some key decisions about the vaccine’s approval, vaccine recommendations, cold chain requirements, and recommended priority populations I’ll expect to see a final Operational Plan which will flesh out many of the details.

Stephanie Innes wrote a good detailed article about the Plan in the Arizona Republic this weekend.

Dr. Gerald’s Latest Analysis of AZ’s COVID Trajectory

Dr. Gerald is now producing his weekly epidemiological review mid-week so you can expect to see these posts on Friday now instead of Sundays. Here’s the full report and the narrative intro discussion (below):

“This past week, case counts have continued to trend upwards along with hospitalizations. If these trends continue, it will be a rough Thanksgiving – Christmas – New Year holiday.  While a bit semantic, I would not characterize current growth rates as exponential. The increases, so far, seem moderated as compared to early this summer. Admittedly, the potential for such growth exists and circumstances could change abruptly.

I can’t point to a specific policy change that underlies this resurgence. It seems to be a combination of “pandemic fatigue” and slow normalization of social interactions among families, friends, schools, and businesses. In this regard, specific solutions are not abundantly clear.”

AHCCCS Scores $31M Opioid Grant

AHCCCS has been awarded a 2-year $31M grant from HHS to provide prevention, treatment and recovery services to individuals affected by opioid use disorders and/or stimulant use disorders.

Contracted health plans and community partners’ efforts will focus on populations that have identified unmet needs, including individuals in rural and isolated areas; veterans, military service members and military families; pregnant women and parents with opioid use disorder; individuals experiencing homelessness; tribal populations; individuals who have experienced trauma, toxic stress or adverse childhood experiences and individuals re-entering the community from correctional settings.

A Proposal to Reorient Contact Tracing for COVID

– By Bob England MD

Background on the trends, behavior & transmission of COVID

The events of the past week involving the White House, and the news coverage of them, have demonstrated all too well the continuing ignorance of basic truths regarding the COVID pandemic.  More than 7 months into this, concepts as simple as incubation time, infectiousness, quarantine, and isolation remain misunderstood by public officials and newscasters alike.  Conflicting perceptions are not only the result of inattention to information, but are fueled by deliberate distortion of that information to suit individual interests. 

All of this, combined with a natural exhaustion from social mitigation measures, have driven many to disregard simple protective actions and to engage in truly reckless behavior.  Young people, with their natural sense of immortality, have engaged in unprotected partying.  Both young and old have flocked to high-risk settings such as indoor bars and restaurants, theaters, and gyms.

Others, taking their cue from leaders who proclaim the pandemic to be a hoax or at least a minimal threat, have participated in church services, political rallies, or other mass gatherings with little or no protection.  Still others, responding to social and political pressures, have taken to the streets in mass protests that involve, at best, sporadic social distancing and masking.

All of these, as exemplified by the now infamous White House gathering held to formally announce the latest Supreme Court nomination, have created ample opportunities for so-called “super spreader” events.  What is not generally appreciated by the public, and not adequately addressed by public health agencies, is that the entire pandemic may be primarily driven by such events.

Much has been made of the overall transmission rate, the R0, of the COVID pandemic. But the R0 is merely the mean transmission rate — how many new infections, on average, result from a single existing infection.  That’s an important statistic, and it is true that if the R0 is greater than 1, the epidemic curve is increasing, while if it is less than 1, the number of new infections is decreasing.  But like all averages, there can be a lot of meaningful differences between the mean, median, and mode.

In the case of this pandemic, it appears that many people infected with the virus do not transmit the infection on to anyone else.  In other words, the median and mode of the transmission rate are smaller than the mean.  Perhaps that is due to all the attention to this disease and the desperate desire of most infected persons to not infect others in their family or immediate social sphere.

Rather, most new infections may be occurring in clusters, either in these so called “super-spreader” events or smaller clusters of several infections among participants in group gatherings, wherein a small number of infected persons manage to infect several others at a single opportunity.

This has huge implications for the control of the epidemic, including the appropriate use of contact tracing.

Basics of Contact Tracing

Contact tracing was developed as a public health tool primarily for diseases in which there was a useful intervention for persons known to be exposed.  If we had a preventive treatment that could be given to exposed persons while they were still incubating the infection but not yet ill, we could use contact tracing to find them and treat them, preventing cases of disease.  Examples include tuberculosis, certain sexually transmitted infections, bacterial meningitis, and so forth. 

Even if we didn’t have such a preventive treatment, we sometimes use contract tracing to inform and educate exposed persons if either:

  • they could watch for symptoms and avail themselves of early treatment;  or

  • modify their behavior or even quarantine themselves so that they didn’t further transmit the disease to others until enough time had passed that we were sure that they could no longer do so. It is with the latter objective that we might try contact tracing with COVID to lessen spread of the disease. That’s the basis for the 14-day quarantine period for those known to have significant exposure to a person with COVID.

However, contact tracing has always been more effective with diseases that are relatively less common, well diagnosed, and thus easier to track.  We’ve never tried contact tracing with influenza, for example, even though it kills an average of 20,000 Americans each year, and sometimes 60-80,000 or more.  It’s simply too widespread, and too often unrecognized, for us to attempt to identify contacts. 

Instead, every year, we declare that there is “community-wide spread” of flu, and we tell everyone to behave as if they may be exposed every single day.  Now we are in a situation where at times, there are more active COVID infections and more community-wide spread than in any typical flu season.  

So how do we use contact tracing to address COVID?

The Reality of COVID Numbers & Contact Tracing

During the peak of COVID transmission in Arizona, we were reporting more than 1,000 cases per day.  All indications are that we should expect new infections in that range during the winter months, soon to come.  Early on, the unavailability of testing, combined with the predominance of asymptomatic or mildly symptomatic infection, led to estimates of perhaps 50-times the number of true infections to reported cases.  This was borne out by early seroprevalence studies in California. 

As testing became more available, estimates from CDC indicated perhaps a ten-fold incidence of true infections to those reported.  For the sake of argument, the rest of this paper will assume that this has been further cut in half, so that the number of true infections to those reported is only 5-fold. This is an optimistic assumption, given wide variability in the sensitivity of tests, the rate of truly asymptomatic infection (varying from 20% to 50%, depending on the study), the continued barriers which exist to testing, and the reporting issues that persist from the increasingly common point-of-service tests.

So let’s assume that as we again approach 1,000 case reports per day in Arizona, we are actually experiencing 5,000 new infections per day. Let’s say that if we attempt traditional contact tracing, we’ll somehow interview all of those 1,000 reports and identify 5 close contacts per case.  So that’s 5,000 contacts per day, whom we should then contact and tell to stay in quarantine for 14 days from their last exposure to the case.  5,000 contacts x 14 days means that on any given day, we would have approximately 70,000 people, or ~1% of the entire population, in quarantine.  And that’s an ideal number. 

But each of the 4,000 real infections that we don’t know about will also, in reality, have the same 5 contacts each.  So there will be an additional 20,000 contacts, each and every day that we cannot notify, or 280,000 contacts at any one time who should be in quarantine, but that we can’t know about.

Thus, we’ll only ever be able to notify 20% of those we should, and that’s if every single reported case responds to our call, and divulges every single contact.  That’s far from reality.  In reality, under the best of circumstances, with such a widespread infection and typical compliance, we’ll be lucky if we can notify even 10% of those exposed.

In addition, most of those contacts will be well-known to the reported individual.  Often they will be family members, even living in the same household.  They will mostly have already been informed by the reported case.  If requested, the case will usually also be willing to notify most others.  Thus, simply educating the case and asking him/her to notify those who may have been exposed will usually satisfy.

In other words, while it’s not a bad thing to notify exposed persons, it will have little to no effect toward containing the pandemic.  It’s just not possible to use a traditional contact tracing strategy to turn the epidemic curve around.  Infections must be much less frequent, and nearly always identified, before we can use it effectively in that manner.

The proposed new look-back contact tracing method

So instead, let’s put our effort toward making more of a difference.  Given that most (some estimates are up to ~80%) of infections are due to mass events, let’s ask about them, and pursue them.  Doing so might spur testing and identification of many attendees who would otherwise never have been identified, allowing them to self-notify their own contacts.

In addition, it will draw attention to the otherwise unpublicized events causing mass infection, and may therefore cause behavior change to limit their existence in the future. Even if it doesn’t fully impact behavior in the desired manner, it’s certain to have a better chance at doing so than our current strategy of remaining blinded to the consequences of mass gatherings.

So, rather than always looking forward, and asking each case who they may have exposed from two days prior to symptoms or positive test result and onward, let’s simply tell them that they need to notify such persons themselves.  Then ask the following:

During the 2 weeks prior to your onset of symptoms (or if asymptomatic, 2 weeks prior to positive test):

  • Did you attend any group gatherings?  (Such as a party, reception, wedding, funeral, church service, political rally, political protest, sporting event, attendance at a bar, or a restaurant, etc.)

  • If yes,

  • Roughly how many people were present?  (Not just at your own table, for example).

    1. How long did it last?  How long were you there?

    2. Indoors or outdoors?

    3. Was everyone masked?  Or how many?  Were you?

    4. Who organized it?   Or what was the venue?  (e.g., bar or restaurant)

Then it’s up to the jurisdiction how to pursue.  Ideally, we would contact the organizer to get more details, contact info, and follow-up with each attendee.  More likely, depending on the threshold decided upon by the jurisdiction (see options below), make a public announcement.  To wit:

“Anyone who attended X event at X location on X date should be aware that COVID transmission likely occurred there. You should quarantine yourselves for 14 days from the date of the event, seek testing now and at the completion of the 14 days, and if you have any symptoms, contact your healthcare provider for advice.”

The threshold for such an intervention might be a single case identifying a suspect event, or two or more case reports naming the same event. 

This is a real opportunity for education that might strike home.  It’s purely anecdotal, but in my own experience working in STDs, patients who should have well understood their own risk behaviors and risk factors would suddenly sit up and take notice when notified that they were a contact to HIV.  I was surprised that they were surprised, but there is something in human behavior that we take notice once it becomes more personal.   

So tell people.  “If you were at Restaurant/Bar X on Date Y, it appears that some persons there contracted COVID.  You should….” 

Not only will that make those at a particular bar on a particular night take notice, but anyone who has been foolish enough to patronize the same location on other nights, or any other crowded venues, will also take notice, and hopefully not do it again. I think this would be especially helpful for bars, where large numbers of people congregate seemingly without concern.  Publicize several dates at several bars, and people will think twice before patronizing them again. 

I know this is a long shot.  Not particularly politically correct during a time when the emphasis is on re-opening.  But we need to reopen without ridiculously risky venues being open indoors, without social distancing or masks, or the sporadic superspreading events will continue to fuel our infection rates, and may force the elected officials to shut everything down again. 

Backwards contact tracing won’t just identify more missed cases, it may help communicate the true risks going forward.