Author: Will Humble

Updated 4/14/20

Should the Best Available Data or Worst Case Scenarios Drive Public Health Policy?

Imagine you’re an elected official and you need to increase hospital capacity to respond to a pandemic.

Imagine you don’t have a national health system like the UK, so you need to issue executive orders to compel the hospitals you regulate to increase capacity at their own expense.

How do you decide what to order the facilities to do? What percentage increase in their bed and ICU capacity should you require them to implement?  How many ventilators should you acquire?

State-of-the-art modeling using the best available data may be your best bet for informing important policy decisions.

At the beginning of an epidemic there may be unreliable data with which to use in the model. As the epidemic progresses more data becomes available, it allows you to refine your model and your policy directives.

That’s where we are right now.  It’s time to use better modeling to improve the evidence base for policy directives.

On March 26, the governor issued an executive order directing AZ hospitals to increase their bed and ICU capacity by 50% by April 24.  Half of that increase needs to be in place by yesterday (April 10). The media release announcing the Order said that it’s based on a worst-case scenario.

But is it best to base public policy on a worst-case scenario?

That depends on who is paying the invoice, doesn’t it?  If you’re a hospital that’s responsible for complying with the order, perhaps you’d rather see it based on more likely scenarios using models with contemporary data.  If you’re an elected or appointed official who’s not paying the bill, perhaps you’d rather see the Order based on a worst case scenario to cover your downside risk. 

Our elected and appointed health officials and public health staff are busy putting together a host of response plans designed to minimize the health impact of the virus.  Modeling should be a key element in those plans.  It’s always best to use evidence-based criteria in planning, especially when you’re asking private hospitals to expand their capacity at their own expense.

New evidence suggests our interventions are working

Indeed, there’s evidence that our social distancing interventions are working, providing new information that our policy-makers should consider as they consider their interventions.

For example, an Arizona public health associate professor has released a COVID-19 disease outbreak outlook that suggests our Arizona interventions are working. Joe K. Gerald, MD, PhD, acting in a personal capacity, studied data from Arizona COVID-19 cases and states…  “Mounting evidence indicates that social distancing, including the current stay-at-home order, is slowing the spread of new infections.” He also says the “lag between new infections and hospitalizations and ICU admissions means that the pace of these outcomes will increase for the next 1-3 weeks before slowing.” Here’s the analysis and discussion (results from 4/14/20).

The results also suggest that our aggregate hospital system is already adequate to handle the peak number of cases. With that in mind, does it still make sense to require hospitals to cancel all of their elective procedures and increase their bed and ICU capacity by 50%? Those directives are putting intense financial stress on our hospital system and at this point are likely doing more harm than good (as long as folks still continue to practice good social distancing).

We urge our policy makers in Arizona to tap our University expertise (like Dr. Gerald) and use their analyses to adjust their interventions and directives.  Evidence based policy-making demands it.

P.S. Here’s a good article from the Arizona Republic that talks about the financial impact that these Executive Orders are having on our hospital systems.

P.S.S. Here’s a good high-level 10-minute You Tube video about how models are developed and can (and should) be used.

P.S.S.S. The ADHS began displaying COVID-19 cases by Primary Care Area or ZIP Code ion 4/12, including hospital capacity data. That data is posted here.

State and local officials are looking for emergency response volunteers to help with the COVID-19 response.  Your knowledge and skills can make a difference.  If you’re interested in volunteering you can register with the “Arizona Emergency System for the Advance Registration of Volunteer Health Professionals” (AZ-ESAR-VHP) at Arizona Emergency System for the Advance Registration of Health Professionals.

The State Disaster Medical Advisory Committee met last week and approved Crisis Standards of Care Staffing Guidance for Short-Term Acute Care Facilities; COVID-19 Pre-Hospital Triage Guidance; and COVID-19 Guidance for Expansion of Healthcare Facility Staff.

If you go to those links you’ll see that the guidance provides suggestions for how to go through the decision-making process for alternate care standards rather than actually making alternate standards care decisions.  

Here’s the Roster of people on that committee.

The University of Pittsburgh School of Medicine published a peer-reviewed paper this week in EBioMedicine suggesting that their COVID-19 vaccine candidate produces antibodies specific to SARS-CoV-2 (in mice), at quantities thought to be sufficient for neutralizing the virus.  The vaccine would be delivered through a fingertip-sized patch. This is the 1st peer-reviewed study that describes a candidate vaccine for COVID-19.

The paper titled, “Microneedle array delivered recombinant coronavirus vaccines: Immunogenicity and rapid translational development” is in EBioMedicine.

The anti-vaccination crowd sure has been quite these days, don’t you think?

Last week the FDA issued an emergency use authorization for hydroxychloroquine and chloroquine as treatments for COVID-19. The authorization allows the drugs to be donated to the Strategic National Stockpile and distributed as well as prescribed by doctors to hospitalized adult COVID-19 patients as appropriate.  They could have been used off-label before the authorization, but this determination remove the SNS administrative barrier.

On Saturday the governor issued an executive order limiting hydroxychloroquine prescriptions to people that need it for treatment (e.g. Lupas or COVID) and clarified that it can’t be used for prophylaxis (prevention).  Good idea.

The CDC has a web page that summarizes the trials underway including for Remdesivir, which is an investigational intravenous drug with broad antiviral activity that inhibits viral replication through premature termination of RNA transcription and has in-vitro activity against SARS-CoV-2 and in-vitro and in-vivo activity against related coronaviruses.  More information on trials can be found at:  https://clinicaltrials.gov/.

Is There Evidence for this Intervention?

• People that have respiratory symptoms or fever should stay home and not be out and about right now (with or without a mask).

• Cloth masks or home-made masks and scarfs are fine for asymptomatic persons to wear in the community (but likely provide little protection for the wearer or community members).

• Members of the community should not wear manufactured medical masks if they are asymptomatic. Doing so puts additional pressure on the PPE supplies and putting additional strain on health care workers.

• However, cloth masks might remind people to stop touching their faces and also remind people to keep their distance from others (perhaps the mask can provide a visual queue to keep some distance).

The CDC is now recommending the voluntary use of cloth face masks by everyone in the community regardless of whether they’re sick. 

There is some evidence to support the use of cloth masks for people that have any respiratory symptoms (during this pandemic) as a recent study supports the use of surgical face masks to prevent coronavirus transmission from symptomatic individuals.  There’s widespread consensus that people working in healthcare and people that have any respiratory symptoms in the community should wear facemasks.   But- there’s little if any evidence to support the use of face masks for those who are not symptomatic in the community.  

Given the shortage of PPE in healthcare settings and the demand that would be placed on the supply chain from widespread use of manufactured medical masks, the only reasonable recommendation is for people without symptoms to wear cloth masks, scarves or homemade masks- not manufactured medical masks.

There’s very limited data on the efficacy of cloth masks. There are some small studies (1, 2, 3) showing that cloth masks can provide some level of marginal protection against particles which can contain viruses. If a covering gets wet (even from the moisture emitted when a person exhales) the fabric could be more likely to transmit the virus.

One randomized trial compared medical masks, 2-layer cotton cloth masks, and usual practice in hospital health care workers (n=1607).  The cloth masks were 2-layer cotton masks.  Participants were asked to wash them daily with soap and water.  The study found that the highest rates of influenza-like illness were in the cloth mask group (RR =13.0 compared to the medical mask wearers).

Infections were also higher in the cloth mask group compared to the usual practice group. Cloth masks also had higher rates of laboratory confirmed virus in participants (RR 1.7 compared with the medical mask group).  Penetration of cloth masks by particles was almost 97% compared to 44% in medical masks.

Arizona has now received 75% of our allocation of personal protective equipment (gloves, masks, gowns, hoods) from the Strategic National Stockpile.  The goods come in to the ADHS warehouse from the SNS and are shipped to the county/tribal health departments, who then prioritize where the PPE will go.  Most are continuing to prioritize inpatient facilities.

In the mean-time, individual hospitals, community health centers, skilled nursing facilities and healthcare providers of all sizes are continuing to pursue PPE from their usual wholesalers.  I presume that the state of Arizona is doing the same.

The bottom line is that there is only so much PPE in the world and it is in super high demand everywhere.  The primary manufacturers are in China, which is now just in the process of getting their manufacturing industries up and running.

It’s unfortunate- but for the duration of the pandemic healthcare providers of all types won’t have the personal protective equipment that they have been accustomed to having their entire career. 

The CDC has a website with some practical guidance to help healthcare providers conserve their PPE  – they call it strategies to optimize the use of PPE. The site has separate guidance for masks, gloves, gowns, respirators, and ventilators.  There’s also a PPE Burn Rate Calculator to help facilities calculate the use as they go.

Most facilities are probably already using Contingency Level conservation methods- and there is a good chance that’ll progress to the Crisis Level at some point in the next few weeks.  Here’s a link to the state’s Contingency PPE Guidance.

Last week The Lancet published a new study examining the case and infection fatality ratios for the pandemic.  The case fatality ratio is an estimate of the fraction of people that have been confirmed to have the disease that end up passing away.  The infection fatality ratio on the other hand is the fraction of people that pass away that have been infected with the virus (the infection fatality ratio includes asymptomatic cases).

The author’s best estimate of the case fatality ratio is 1.38%. Of course, there’s a big difference in the case fatality ratio by age. The ratio was a lot bigger in older age groups, with a CFR of 13% among people aged 80 years or older.  Their estimated overall infection fatality ratio is 0.66%, also with an increasing profile with age.