27 December 2020 Blog Post: On Rapid Antigen Testing

27 December 2020 Blog Post: On Rapid Antigen Testing

As those of you who have visited our offices during the COVID-19 pandemic will know, we have relied on rapid antigen testing as both a screening and diagnostic tool since they became available. There are a number of advantages to rapid antigen testing – but the main one is in the name – they’re rapid.  With results in 10-15 minutes, rapid antigen testing was a cornerstone in our ability to reopen our office safely and confidently.

The major concern with antigen testing, unlike PCR which gets sent out to a lab and can take days to return, is reliability.  Because antigen tests  look for antigen proteins on the surface of the virus instead of traces of the virus’s RNA, they simply are less accurate.  But how much less accurate?  And, equally importantly, if used as a measure of one’s infectiousness (i.e. ability to transmit the virus), do we need a test to be as remarkably sensitive as PCR?

We have performed hundreds of antigen tests in the preceding months, and for a subset (a total of 144) of these we collected and sent concurrent PCR samples.  Of the 144 that we collected, 2 had positive antigen results which were both subsequently confirmed by PCR.  But, there were 2 additional samples that tested negative on the antigen test but later returned positive from PCR.

Two primary characteristics describe the clinical utility of a diagnostic test.  The first is sensitivity – which is the probability that a test result will be positive when the disease is present (true positive rate).  The second is specificity – which is the probability that a test result will be negative when the disease is not present (true negative rate).  In our sample, the sensitivity of the rapid testing is poor, only 50% (error range: 6.8% to 93.2%) but the specificity is 100% (error range: 97.4% to 100.0%).  

In a low prevalence population with a 2% infection rate, the rapid antigen test functions quite well.  A positive test result would be expected to be a true positive 100% of the time.  A negative test result would be expected to be a true negative result 99% of the time. Overall accuracy:  99%

However, in a high prevalence population, such as we are in now, with a 16.6% infection rate, this testing modality becomes significantly less accurate but not useless.  A positive test remains 100% predictive but a negative test likelihood drops to 90.9%.  Overall accuracy:  91.7%.

Our primary concern moving forward would be to substantially decrease the number of missed infections. For example, in our experience we have missed two times as many infections as led to believe. On the other hand, we successfully identified 140 of 142 negative infections. To quote Dr. Meagan Fitzpatrick writing in the Lancet (link: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32635-0/fulltext):

“Should rapid testing become a viable, trusted screening strategy for control of COVID-19, performance characteristics should be well understood and screening strategies should be designed with test imperfections clearly in mind.”

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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26 December 2020 Blog Post: What Is Happening in Los Angeles? Looking at Prevalence and Why It Should Scare You

26 December 2020 Blog Post: What Is Happening in Los Angeles? Looking at Prevalence and Why It Should Scare You

Prevalence is one of the earliest concepts covered in an introductory Epidemiology course is that of prevalence. Defined, prevalence is “the proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time.”

Determining the true population frequency of COVID-19 would be a massive, time consuming and expensive undertaking.  It would require public health officials to conduct periodic large-scale surveillance testing via random sampling.  Fortunately, Drs. Chiu and Ndeffo-Mbah from Texas A&M University found that prevalence rate for COVID-19 can be predicted, with a 7-day lag, by the geometric mean of reported case and test positivity rates averaged over the previous 14 days.

So how does this apply to Los Angeles County?  Well I did the analysis – and it’s scary.

RIght now, when you read press reports or watch television or even read this blog, you are inundated with the massive case rate.  But as these numbers rise higher and higher, the practical impact is lost.  Or, as Dr. Naomi Wolf commented on my Twitter – “un-annoted ‘curve’ w/steep upper right is often being used to wave at people’s faces to scare them without data.”  Prevalence is a much more relevant number, and one that illustrates the magnitude of our public health crisis here in Los Angeles.

My intention with Figure 1 below is, in fact, to scare you.  But with data.

The current prevalence in Los Angeles County stands at 16.6%.  This means that 16 out of every 100 individuals in our County right now, as you read this, has COVID-19.  Has it as in they are actively infected, shedding virus and able to infect others.  Get 10 people together, two people have it.

During the summer “peak” of cases, the prevalence peaked at 2.6%.

The biggest predictor of an individual’s risk of acquiring COVID-19 is the population prevalence.  This current number of 16.6%  should scare you.  The slope of the prevalence curve  which has absolutely skyrocketed since mid-November should scare you.  The fact that there are two approved available vaccines that are not being distributed widely or rapidly should scare you as vaccination is our only way out of this mess.

These data – should scare you.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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19 December 2020 Post: Los Angeles Mortality Rate

19 December 2020 Post: Los Angeles Mortality Rate

Los Angeles County continues to (dubiously) seek higher and higher ground when it comes to COVID-19 incidence and mortality rates (Figures below) This week, we have 3.7 times more cases than we did over the summer. Mortality rates reached a new high at 0.53 daily deaths per 100,000 population – the previous maximum was 0.44 in late July. Not sure there is any good news here as the County reported significant delays and backlogs in testing. Although the slope of this week’s curve flattens slightly compared to the week prior, it may simply be due to under-reporting. Hospitals and ICUs are swamped. And yet another round of holiday travel is upon us.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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15 December 2020 Post: Healthcare workers receiving their COVID-19 vaccine

15 December 2020 Post: Healthcare workers receiving their COVID-19 vaccine

Today social media and press reports will be flooded with pictures of healthcare workers receiving their #Covid_19 vaccine. While an accomplishment worth celebrating, the reality for the rest of us looks like this. Test, trace, isolate.

More cases —> more hospitalizations —> more ICU transfers —> more deaths

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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13 December 2020 Blog Post: COVID-19 Update in Los Angeles County

13 December 2020 Blog Post: COVID-19 Update in Los Angeles County

Not that long ago I read Hans Rosling’s book “Factfulness” which asks simple questions about global trends and compiles the generally wrong answers given by a wide variety of generally well informed groups.  In the book, the author outlines concrete steps that we can all take to ask questions, take perspective, test our ideas and welcome complexity.  One of the concepts that I find myself returning to is one of comparing numbers  As Rosling puts it:

“Never leave a number all by itself. Never believe that one number on its own can be meaningful. If you are offered one number, always ask for at least one more. Something to compare it with.”

Here in Los Angeles County, local health officials told us that yesterday, another 70 deaths and 11,476 new cases of the coronavirus were recorded. In total, 512,872 cases have been reported and 8,269 people have died of the virus.

I prefer my “other” numbers in the form of a rate.  Readers of my blog will be familiar with the epidemic curve which I have been presenting since March.  Our previous maximum case rate before this surge was the reporting week ending 7/14/2020 – and that rate was 29.59 new daily cases per 100,000 population.  For this most recent reporting week, ending 12/8/2020 that rate was 88.75 (Figure 1 below).

By graphing this week’s numbers, it is immediately obvious how unprecedented the current rise in cases has been.  Even more concerning is the velocity of the rise with the current uptrend starting in the first week of November.  Public health officials seeing a doubling of cases from 11/3 to 11/10 (nearly matching the mid July peak) should have implemented a safer-at-home order, rather than waiting until after Thanksgiving (which was politically expedient but a public health disaster).

There remains a small cadre of voices who care less about case numbers but concern themselves only with mortality rates.  Granted, mortality rates have gone down likely as a consequence of improved in hospital treatment.  However, there is a well worn path of increased cases → increased hospitalizations → increased ICU utilization → increased mortality rates seen since March and demonstrated dramatically when Italy’s health system became overrun early in the pandemic.

Mortality rates in Los Angeles are at similar highs seen in early May and again in late July (Figure 2).  Given that mortality rates tend to lag by several weeks, we will no doubt set new records in the County.

Also yesterday was a protest march from Hollywood to Beverly Hills- to call for a rollback of COVID-19 restrictions [Link:  https://ktla.com/news/local-news/business-owners-supporters-march-through-l-a-calling-for-rollback-of-covid-19-restrictions/]

Here again, Rosling’s advice is enormously helpful – from understanding that “human beings have a strong dramatic instinct toward binary thinking” and that “there’s no room for facts when our minds are occupied by fear.”

Instead Rosling proposes the following equation:  Risk = danger × exposure. 

He goes on to say, “the risk something poses to you depends not on how scared it makes you feel, but on a combination of two things. How dangerous is it? And how much are you exposed to it? •   Get calm before you carry on. When you are afraid, you see the world differently. Make as few decisions as possible until the panic has subsided.”

I cannot think of better and more succinct advice at this time in our County.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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10 December 2020 Blog Post: On COVID Vaccines

10 December 2020 Blog Post: On COVID Vaccines

In a small glimmer of hope in what has been a rapidly deteriorating epidemic in the United States, the FDA yesterday voted 17-4 (with one abstention?) to approve the Pfizer/BioNTech coronavirus vaccine through an Emergency Use Authorization (EUA). This is the same approval process that has brought various testing modalities for COVID-19, including antigen and antibody tests, to market. A full Biologic License Application (BLA) would be much further down the line and require at least six months of follow-up in a substantial number of clinical trial participants. Before today, the Pfizer/BioNTech vaccine had already been approved for use in the United Kingdom, Canada and Bahrain.

I have spent the last several weeks answering questions about this vaccine and other vaccine candidates and will outline the main questions I have been getting below:

How and when can I get the Pfizer vaccine?  Will you have it in your office?

This is a difficult question to answer and I have not heard any concrete plans. Distribution of the Pfizer vaccine is complicated and requires an ultracold chain of storage at -70°C. Vaccines will be sent out via a specialized thermal shipping container. Upon opening the shipping container, the vaccine can be stored refrigerated at 2-8°C but must be used within 5 days. GIven that the minimum lot size is 1000 doses, only large medical centers with adequate storage capacity and the clinical infrastructure to deliver 200 doses a day (and then 200 doses to the same individuals three weeks later) will be suitable sites.

Specifics for distribution beyond transportation from Pfizer’s facility in Michigan to distribution sites have not been well articulated. Tweets from Governor Newsom suggest that California had ordered over 300,000 doses of Pfizer’s vaccine (which would effectively vaccine 150,000 individuals – again if distributed without error)   Those shots are expected to arrive around Dec. 15, Newsom said Monday.  Seven California hospitals will be among the first in the United States to get the vaccine when it becomes available. Cedars Sinai Medical Center, Los Angeles; Mercy Medical Center, Redding; Rady Children’s Hospital, San Diego; UCD Health, Sacramento; UCSF Medical Center, San Francisco; Valley Children’s Healthcare, Madera; and Zuckerberg San Francisco General Hospital are on a list provided by the California Department of Public Health. Health officials are quick to point out that these initial shipments will not be sufficient to vaccine healthcare workers and prioritization will be made for those taking care of vulnerable populations.

It does appear that private industry will also be involved in the distribution of the vaccine.  McKesson Corporation, the major source of medical supplies and well known for their logistics and robust supply chain management, has been identified as a “preferred vendor” by the US Government.  Pfizer, however, has taken pains to specifically not use McKesson and instead said in press releases that they would deliver the vaccine directly to healthcare providers. Also, there has been some discussion that CVS and Walgreens will store and distribute doses of the vaccine destined for long-term care facilities.  Each dose has been estimated to cost about $20 (it will be interesting to see what insurance companies actually reimburse upon delivery).

I do not anticipate having the Pfizer particular vaccine available in my office and have received no communication from our usual vaccine suppliers. In fact, I have not even received communication about how I myself might obtain one as a healthcare worker – not from the State, County or the hospital where I am on staff. But I do think that the Moderna vaccine (detailed below) and potentially the AstraZeneca will be much more viable in-office solutions and, for those over the age of 65, may even be available as early as January.

The other limiting factor in generalized availability of the Pfizer vaccine is that the US government has declined to purchase additional doses beyond the original 100 million doses (which would effectively vaccinate 50 million Americans if distributed perfectly) negotiated in July. In the interim, other countries have stepped in to order the vaccine and would now be prioritized before the US. This includes the UK (40 million doses), Japan (120 million doses in preparation for the Summer Olympics), and the European Union (200 million doses with an option for 100 million more). Additional Pfizer vaccines would most likely not be available to the US until June or July.

For those who are not frontline healthcare workers or long-term care facility residents, the wait for a Pfizer vaccine will likely be considerable. There are at least 18 million health care workers in the US (1.7 million in California). There are 1.3 million long-term care facility residents (400,000 in California). Given that each vaccination series is two doses, separated by three weeks and that clinical studies suggest that protection is attained fully at week 5 from the first dose. I think most realistic estimates suggest that late Spring or early Summer will find the vaccine available for the general population.  It is also important to remember that the vaccines have yet to be evaluated for safety in those under 18 or in pregnant or breastfeeding women.

Fortunately, there are other options.

What about the Moderna vaccine?  And will you have that available in the office?

Although there has been a general outcry about the US not purchasing additional Pfizer vaccine (spearheaded by Dr. Scott Gottleib, former FDA commissioner and now a Pfizer board member – clearly not an unbiased voice), the good news is that there are other effective vaccine candidates that are also near FDA approval.

The next candidate will be the Moderna vaccine which was developed in partnership with the National Institutes of Health (NIH),  It, like the Pfizer vaccine, is also on an mRNA platform and is a series of two injections spaced 3 weeks apart.  The FDA will review Moderna’s application on December 17th and a quick approval is expected.  Both the Pfizer/BioNTech and Moderna vaccines have been shown in large trials to reduce the risk of developing symptomatic Covid-19 infection by more than 90% and severe disease by 100%.  

The Moderna candidate vaccine has far less stringent cold chain requirements. Moderna’s vaccine remains stable for six months at negative 20°C and for 30 days in a standard medical refrigerator.  That difference makes Moderna more suited for distribution in individual physician offices as well as rural areas which have been decimated by a preference for large, metropolitan regional hospitals.

Cost?  $32-37 per dose.

What about the AstraZeneca vaccine? 

The vaccine immediately on the heels of the Moderna vaccine is AstraZeneca’s candidate developed in conjunction with Oxford University. It is also given in a two shot series, separated by four weeks. Unlike the Pfizer and Moderna vaccines, AstraZeneca says its vaccine can be stored, transported and handled at normal refrigerated conditions for at least six months and administered within existing health-care settings. Also, unlike the other two vaccines which were developed on an mRNA platform, the Oxford–AstraZeneca vaccine is made from the common cold-causing adenovirus that was modified so that it no longer replicates in cells. 

Its cost is expected to be $2.50 per dose.

The raging controversy, however, with this vaccine candidate is that its efficacy is quite different depending on the strength of inoculation given.  One dosing regimen showed an effectiveness of 90% when trial participants received a half dose, followed by a full dose at least one month apart. The other showed 62% efficacy when given as two full doses at least one month apart.

The combined analysis from both dosing regimens found an average vaccine effectiveness of 70%. No hospitalizations or severe cases of the disease were reported in participants receiving the vaccine. The difference in the two dosing regimens was not deliberate, but was actually a manufacturing mistake. It is still not clear why there is such a difference in effectiveness – some have suggested it may simply be a statistical fluke in the data (the half dose/full dose group did not include anybody over the age of 55). However, others have suggested that the lower initial dose may actually ‘prime’ the immune system making it a more effective way to vaccinate.  I wonder if then the first half strength dose would only be $1.25.

What sort of timeline are we looking at? 

This is a good question and one subject to all sorts of conjecture. In my search for something concrete, the timeline most easily understood came from the State of Massachusetts pictured below (Figure 1)

On their website, the Massachusetts Department of Public Health notes that “the timeline reflects several priorities: protecting our most vulnerable, maintaining health care system capacity, and addressing inequities in health care access and COVID-19 burden.”  Unknowingly their timeline also reflects an essential public health underpinning which is that you want to prioritize those settings responsible for continued spread of the virus such as congregate care settings (corrections and shelters). Each phase will undoubtedly be broken down further.  For example, in Phase One: healthcare workers and support staff working in ICUs should be prioritized before those working in an outpatient setting.  In Phase Two, it is more likely that age groups will be subtiered as 85+, 75+, 65+ and so on.

But in general, I think this timeline will hold with much of the US public having vaccine availability in late Spring or early Summer.  But that’s still a very long time away, particularly as the pandemic accelerates in our community.

What about vaccine side effects? 

Two healthcare workers in the United Kingdom who received Pfizer’s newly approved COVID-19 vaccine did develop a severe allergic reaction after their first dose.  Of interest, both have a history of significant allergies (perhaps to medications or to an environmental trigger like a bee sting), and both carry EpiPen injectors at all times. Although these individuals are recovering well, the UK NHS has advised that those with a history of significant allergic reactions not receive the vaccine at this time as further investigation is undertaken.

It is important to note that vaccine trials rely on the participation of healthy adults and individuals with a significant allergy history would have not been eligible for participation.  Similarly, the medications have yet to be studied in adolescents (although those clinical investigations are now ongoing), or among pregnant or breastfeeding women.

The good news for the general public is that healthcare workers will function as a large scale trial before the vaccines are distributed more widely.  A diverse workforce with (presumably) a close connection to healthcare providers, they should be able to identify and manage any adverse effects from the vaccine and reliably pass that information on to the public.

How do you think things will go from here?

To have any vaccine within a year’s time from the start of the pandemic is an astonishing accomplishment – and even better we now have one approved, one that is nearly approved and one that seems to be a viable candidate. Taking a moment to reflect on the collaborative steps that were required – from the identification of the viral genome, to a narrowed focus on the viral spike protein as a vaccine target, to the recruitment and participation of tens of thousands of volunteers – gives us a sense of just how massive of an undertaking this has been. Typically, vaccine development takes about a decade.

Unfortunately, we are now experiencing an absolutely massive and unprecedented (even by US standards) surge in cases. Some epidemic modeling experts (covid19-projections.com) have estimated that the post-Thanksgiving surge will be 2-3 times our July peak.  I actually think that this is an underestimate and that we will see 10 times the cases we had over the summer with a real potential to overwhelm our medical system. 

Although there have been improvements in in-hospital care leading to decreased mortality, there have not really been any significant advances in outpatient treatment.  And, as we learned from Italy’s experience in March, an overwhelmed health care system significantly worsens survival rates.  Just yesterday in Los Angeles there were over 12,000 reported cases – and only a few months ago there was discussion that if the County could drop below 700 daily cases, that we could move into a less restrictive tier.  Governor Newsom’s careful planned tier system is moot when we now have extensive and accelerating community spread.

Adding onto this already perilous situation is the upcoming Holiday season where, again, we will see Americans traveling and visiting family.  This isn’t smart, it isn’t right and will only serve to flare cases again. I have not yet seen numbers for expected travel over the winter holidays but would expect these to be in line with what we saw over Thanksgiving.

It will be some time before a large enough percentage of the American public is vaccinated to begin to slow community spread. President Elect Biden has promised 100 million doses in his first 100 days – an ambitious goal.  Even if achieved, 100 million doses covers 50 million Americans or 15% of the population. Add to that an estimated 15% of the US population that has natural immunity (assuming here that we do not vaccinate those who have already recovered from COVID-19 which we most certainly would and should do), a maximum of 30% of the population would then be immune to the virus. Most estimates expect that a necessary population threshold to significantly impact community viral spread is a 60-70% “herd” immunity.  Day 100 of a Biden administration takes us to the first week of May – by then we would only be halfway to our goal population immunity threshold

We still have a very long road ahead of us. Most of it along depressing landscape that we have seen before.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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5 December 2020 Blog Post: COVID-19 Update, It Matters What You Do, But It Also Matters When You Do It

5 December 2020 Blog Post: COVID-19 Update, It Matters What You Do, But It Also Matters When You Do It.

On the eve of another mandatory stay at home order, with cases skyrocketing to new daily highs and ICUs reaching their breaking point here in Los Angeles County – an otherwise quiet Saturday seems to be a good day for some reflection.

In my Introduction to Epidemiology course (which I took in the Fall of 1993), we were presented with a standard epidemiologic curve which shows progression of illnesses in an outbreak over time.  It looks something like Figure 1 below.

My professor wryly noted that it was best that an epidemiologist arrive as the outbreak was on its downward slope.  This served two purposes – the first to ensure that the outbreak did not propagate further and,the second, to make it appear as if you had actually done something. In fact, for many outbreaks, they would have tapered off on their own.

The epidemic curve of COVID-19 in Los Angeles County today looks like this:

So by this point in time, we’ve had a couple of go rounds at this epidemic.  From the first wave, to the mid-July surge and now in the current mess we find ourselves – far outpacing our prior peaks. So what have we done wrong?  Why are we not learning anything?

The first shelter-in-place order occurred on 3/23/2020 when the new daily case rate was – wait for it – 2.29.  Restrictions were lifted on 6/12/2020 when the rate was 12.86.  Does anybody notice a problem already? Cases increased 6 fold but we’ve decided to go ahead and open up.

Statewide closure of all indoor activities occurred on 7/13/2020 when the case rate had (predictably) risen to 29.59.  Closure of gyms, indoor dining, bars, movie theaters, and museums was re-imposed, this after most indoor businesses, including bars, restaurants, wineries, and movie theaters had already been shut down two weeks earlier.  Case rates began to decline thereafter.

On 8/28/2020, Governor Newsom unveiled a new set of guidelines for lifting restrictions, titled a “Blueprint for a Safer Economy” and cases were down to 11.95 ultimately dropping to a new low of 7.8 the week of 9/8/2020

On 10/1/2020 Los Angeles County Public Health announced their timeline for sector reopenings within the rubric of the Governor’s blueprint.  Except by that point, our case rates had crept back up to 9.61 and, you guess it,, rose even further as restrictions were loosened making a steady upward march and then a rocket-like acceleration to the current rate of 45.14.

All I have done so far is describe what has happened in Los Angeles, without going into any of the details of sector restrictions or the myriad of questions that ensue. Questions like: If nail salons can be open, how full can they be? Can we dine indoors or outdoors or only have take out?  Are parks opened or closed? Can we go to the beach?  Can we hike? Can I work out with a trainer outdoors? Can I take an indoors exercise class? Can I go to choir practice? Can I practice my faith indoors or outdoors? Drive in movies? What about trick or treating?  Basketball?  Tennis?  Swimming?  Griffith Observatory? Are golf courses open? Can I go bowling?  Is the entertainment industry an essential business? Do I need to disinfect my groceries? Can I go to the farmers market? Can I visit my neighbors in their home?  In their backyard? Can my kids go back to school? Can I have a drink at my local bar? Can I go dancing? Are preschools open? Can I visit a family member in the hospital? In a skilled nursing facility?  In a residential care facility?

Let’s break this down as if we were students in a first year epidemiology course… not only does it matter what you do, it matters when you do it.

You can ask a paragraph of specific questions or you can leave the public with the simple truth – your risk of becoming infected with COVID-19 is a function of three factors:  prevalence, proximity and duration.  The more people infected in the population – the more likely you are to catch it.  The closer you are to an infected individual – the more likely you are to catch it.  The longer you are around an infected individual – the more likely you are to catch it.

At every single point we ‘reopened’ the County, cases were rising. So the specifics of what we did were overridden by ill considered timing.  The same way that a rising tide lifts all boats, a rising prevalence rate increases your chances of becoming infected.  We reopened into the tide of rising cases in June and again in October.  When we have closed, we never had the patience to stay closed or never had the capacity to identify and shut down specific locations of where cases were transmitting, even at a low level.  When we had COVID-19 pinned down in September, we all went away for Labor Day holiday and spread the smoldering embers around again.

So, to our public health officials, this isn’t rocket science. You want to show up and do something, anything, when cases are decreasing. You want to keep people away from one another and, if that is not feasible, limit the time that they interact.  If you cannot limit the time that they interact (say like in their place of employment), then you need to provide them with daily testing. If people need to eat, they need to do so by taking their food away from the establishment that serves it. If people need to party, they should do so outdoors. If they need to sing, they can sing in the shower.

The public instead has been worn down by the minutiae of how many households can gather in an empty field and the nonsensical closure of parks and outdoor recreational facilities. Quite frankly, we don’t have the stamina for it anymore.

So practically, what can you as an individual do to limit your risk as we stagger towards a vaccine?  It’s a simple three part answer.

  1. Know the population prevalence.  You can’t do much to influence this other than not becoming part of the problem. With case rates hitting historic highs, that should be a cue to be even more vigilant than before.  If you’re asking yourself “is it too much that I am spraying the groceries I have delivered with 10% bleach?” – right now, it’s probably not a bad idea and  it certainly can’t hurt.
  1. Proximity.  How close am I to people I don’t know? If the guy behind you in Peet’s seems a bit too close for comfort, tell him to back off.  Better yet, make your coffee at home.
  1. Duration.  Am I in an enclosed space or in a situation where I cannot physically distance for a long time?  Honestly, I’d be thinking in seconds rather than minutes.  Can I be out of here in 30 seconds?  For what it is worth, I don’t ride the elevator at work.  If you need to shop at a grocery store, be sure to keep moving while you are there – grab what you need and move on.  Preferably stores should have a one way pathway through the store.  If not, shop elsewhere.

Prevalence, Proximity and Duration.  Everything else is just window dressing.

That’s it.  

That’s the blog post.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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2 December 2020 Blog Post: COVID-19 Update, Worse Just Keeps Getting Worst

2 December 2020 Blog Post: COVID-19 Update, Worse Just Keeps Getting Worst

I have a Peanuts coffee cup which quotes the ever morose Charlie Brown as saying “Just when you think things can’t get worse, they get worse.” Los Angeles County is experiencing an unprecedented, asymptotic rise in cases (Figure 1 below). In one month, incident rates have gone from 12.54 new daily cases per 100,000 population to 45.14. The rise has been so dramatic that my trusty epidemic curve now needs a whole new axis, having blown past the previous July 14th high of 29.59. Don’t be reassured by the apparent flattening of the curve in the last week, no doubt there exists a tremendous backlog of cases from the Thanksgiving Holiday.

Deaths, too are rising (Figure 2). And, again, don’t be fooled by the apparent dip this week as reports are most likely delayed from the Holiday.

So here is what is strange – the last case I have seen in my clinic was on August 28th and we have tested hundreds of samples since that time. This is all the more perplexing because we experienced the same rise in cases in March/April and then the same July peak as the rest of Los Angeles (and the country). But I have not seen the increase in cases after Labor Day, the much maligned championships of the Lakers and Dodgers and the massive upswing we are now experiencing. So why is that?

First off, my practice does skew towards those that are older – about 30% of the practice are patients over the age of 65 years. And this is a group who are, undoubtedly, redoubling their precautions given higher risk and the very real prospect of a vaccine around the corner. When looking at LA County’s cumulative rates, those 18-49 years of age do contribute more cases relative to their total population. Those 65 years and above contribute fewer cases than would be proportionately expected from their population size (Link: http://dashboard.publichealth.lacounty.gov/covid19…/).

Location wise, the majority of patients in our clinic (based in Santa Monica) are from the Westside of Los Angeles. And while Santa Monica (274 cases per 100,000 population in the past 14 days) and Pacific Palisades (230.1 cases) are clearly visible on the LA Times’ plot of cases by neighborhood (Link: https://www.latimes.com/…/californi…/los-angeles-county/), these numbers are far lower than Athens Village (1490 cases) and Duarte (2213 cases).Los Angeles County has been non-communicative about the specific activities implicated in this current surge. A thorough search of their available data is essentially non-revealing, although their abysmal contact tracing percentages (60.3% in 7 days) would leave any data nearly useless because of missing information.

However, a recent study (Chang, S et a. Nature 2020: https://doi.org/10.1038/s41586-020-2923-3) of mobility networks based on cell phone data from 98 million US residents does give us significant insight into those setting which disproportionately drive additional infections. These are:

  • Full service restaurants
  • Gyms and fitness centers
  • Cafes and snack bars
  • Hotels and motels
  • Limited service restaurants
  • Religious organizations
  • Physician offices
  • Grocery stores

As I write this, Mayor Garcetti has now announced a new stay-at-home order for the City of Los Angeles.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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