Author: Will Humble

Dr. Gerald updated his modeling analysis today with some concerning (but not surprising) results, given the run-up in all of the dashboard indicators in the last 10 days.. One such conclusion in today’s report is that “… current trends in hospitalizations suggest excess capacity could be depleted by July.”

Hopefully executive branch officials will carefully read the report and implement interventions while there’s still time (see previous blog post). Below are some excerpts from today’s analysis.

Increasing hospital utilization strongly suggests that increasing case counts are attributable to increases in community transmission. If current trends are sustained, excess capacity could be exhausted by July. Banner Health recently reported some of its Maricopa ICUs were already at or near capacity. Because interventions take weeks to take effect, immediate action is needed to avoid exceeding our hospitals’ capacity to provide care.

It is worth revisiting the work of the Arizona State University Covid-19 modeling group (see their preprint). Using an SEIR epidemiological model, they examined various scenarios of physical distancing policies including a comparison of a May 15 (early) versus June 1 (late) re-opening (Figure 10). Dividing their daily estimate of new cases by 4X to derive PCR confirmed cases, they estimated that by the time of this update Arizona would see roughly 1500 confirmed cases per day versus about 7500 per day with early reopening which is roughly tracking current conditions. More worrisome is the future trajectory showing even faster growth without action.

Covid-related hospital utilization continues to increase with excess capacity declining from approximately 30% to <15% over the past two months. While adequate capacity exists, current trends in hospitalizations suggest excess capacity could be depleted by July.

We have good evidence that the Stay at Home Order had been effective at slowing the spread of the SARS CoV2 virus. In each county you’ll see that there had been a slow decline in the ratio of new cases over total cases up until May 26. In pretty much every county that ratio rebounds starting on May 26 and continues today.

The sizable increase in cases, percent positives, ratio of new to total cases, and COVID hospital census in the last 10 days coincides with a week’s incubation period with some time for lab testing since the end of the Stay at Home Order. 

There’s still a little room to spare within most hospitals, but the safety margin continues to decrease. Some hospitals are very close to their ICU bed capacity right now. It’ll continue to be very important to keep an eye on the capacity. When the warning bells go off there won’t be much time to make policy adjustments to increase capacity.

In my opinion there are 5 key interventions that, if implemented immediately, could stem the tide of new cases and hospitalizations:

1. More focus on testing and infection control in assisted living and skilled nursing;

2. Enhance contact tracing;

3. Allow cities to implement mitigation strategies;

4. Require wearing cloth masks in public; and

5. Stronger compliance incentives.

Failing to do the above effectively could result in either a need to implement the hospital surge capacity plan, another Stay at Home Order, or both. 

Note: Saturday night the ADHS changed the way that they calculate available hospital capacity on Hospital Bed and Availability dashboard. Their former approach added theoretical surge beds to both the numerator and denominator (available beds and occupied beds). That approach provided an inaccurate view of what’s really available. The new approach is a better way to portray the data. 

You can see a host of data including several interesting charts on the ASU Biodesign site. There’s more background info in this Horizon clip too.

This week’s journal article addresses the question whether outdoor environments are as bad as indoor environments for spreading the virus. An important question given the outdoor protesting that has been going on- as well as the prolific indoor clubbing that happens in AZ.  

The study below found that indoor SARS CoV2 transmission in indoor environments is 19 times greater than outdoor environments. 

Closed Environments Facilitate Secondary Transmission of Coronavirus Disease

https://doi.org/10.1101/2020.02.28.20029272 

One of the big challenges with the US’ COVID response has been the lack of testing capacity.  In part, those challenges hve been as a result of supply chain issues with the test kits- but also because the test is invasive and requires personal protective equipment. A new test that would be easy to use would make a real difference.  

For the past couple of weeks, ASU’s Biodesign Institute has been pilot testing the saliva-based test.  They have been using comparing results with their new self-administered saliva test to results using the classic nasal swab test.

So far, they’ve found that the saliva-based tests were just as good, if not even better, as those collected from nasal swab tests.

The saliva test is as simple as spitting into a screw-top tube through a straw, making testing way easier and also improving the supply of test kits and bringing the cost of testing. 

A couple of weeks ago several news outlets including The Arizona Republic sued the ADHS arguing that they have a duty to disclose the number of COVID-19 cases and the supply and use of PPE in Arizona nursing homes and assisted living centers. The plaintiffs  believe it’s of particular public interest because the majority of deaths in AZ have come from cases in these facilities.

The state has declined to disclose the information because they believe existing communicable disease confidentiality laws and language in ARS 36-783 (E) prevents them from disclosing the info. That exact language says:

… public health authorities shall maintain as confidential any information or a particular part of information provided under this section that, if made public, would divulge the trade secrets of a person or business or; other information likely to cause substantial harm to the person’s or business’ competitive position.

You can see the ADHS’ response to the suit here. Other arguments made by the agency include that disclosing the information will “Have deleterious effects in the community’s trust that the Department can prevent infectious disease.”

Friday the judge deferred to the Department and ruled that they can continue to not disclose which nursing homes and assisted living centers have cases and how many.  However, CMS has suggested that they will be releasing these data in the coming days

Biotech company Moderna put out a press release this week saying that the initial Phase I results for a small study of 45 volunteers found that their experimental vaccine worked and had minor side effects. On the efficacy side of the table, they found that:

“…Dose dependent increases in immunogenicity were seen across the three dose levels, and between prime and boost within the 25 µg and 100 µg dose levels. All participants ages 18-55 (n=15 per cohort) across all three dose levels seroconverted by day 15 after a single dose. At day 43, two weeks following the second dose, at the 25 µg dose level (n=15), levels of binding antibodies were at the levels seen in convalescent sera (blood samples from people who have recovered from COVID-19) tested in the same assay. At day 43, at the 100 µg dose level (n=10), levels of binding antibodies significantly exceeded the levels seen in convalescent sera. Samples are not yet available for remaining participants.”

“At this time, neutralizing antibody data are available only for the first four participants in each of the 25 µg and 100 µg dose level cohorts. Consistent with the binding antibody data, mRNA-1273 vaccination elicited neutralizing antibodies in all eight of these participants, as measured by plaque reduction neutralization (PRNT) assays against live SARS-CoV-2. The levels of neutralizing antibodies at day 43 were at or above levels generally seen in convalescent sera.”

In other words… among the small number of participants (n=12) for which data are available, there was an immune response that may be immunogenic (it works).

So, the DOW stock market index went up 700 points that day because of this news (traders said that’s why it went up at least). Seems like a pretty tenuous reason for such a rally (on an n of 12!).

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UK COVID-19 Vaccine Project Data Shows Efficacy

Six vaccinated macaques and three unvaccinated control macaques were exposed to the virus a month after receiving one dose of the vaccine. The team saw a significantly lower number of viral particles in liquid and fluid taken from the lungs of the animals in the study that had been vaccinated compared with the controls. Here’s more on that “study”