Tag: Masks

Categories
COVID-19

State of The Disunion

A look today at how we’re doing with COVID-19. First let’s look at my home region, Riverside County. Like much of the country Riverside is seeing significant increases in new daily cases. Over the last week or so we’ve been seeing over 500 new cases each day on most days. Yesterday, Riverside saw its highest daily increase yet with 631 new cases in 24 hours. That compares to fewer than 100 cases per day on most days in mid-April after the initial surge and when social distancing orders were in place. Other metrics are moving in the wrong direction as well: hospitalizations and ICU admits are up but still manageable, the percent-positive rate is up, and doubling-time (time it takes for cases to double) is down. The doubling time maxed out at around 33 days in Riverside a few weeks ago but has now slipped to around 28 days. This is perhaps the most worrisome signal that we’re losing control of the virus in this region. If this trend continues we’ll edge closer and closer to the risk of exponential growth we faced at the beginning of the pandemic. A discussion of exponential growth is beyond the scope of today’s post but at the bottom I’ll post a video of an excellent and understandable explanation of exponential growth and why it isn’t intuitive for most people. The percent-positive rate (rate at which Riverside County’s COVID-19 tests are coming back positive) is at 10%. This is up from a low of around 5 in early May. What this indicates is that our increase in cases is not merely due to increased testing as some political leaders suggest but in fact a true representation of increased prevalence of the virus in the community. Hospitalization rates are an important factor to watch. Daily new cases can be affected by testing rate and the reporting of daily new cases often lags behind as reporting may be slower from sone agencies. Rising hospitalizations show in real-time how a region is doing because it’s a measure of how many people are quite sick, now. Keep an eye on hospitalizations. More people don’t get sick enough to be hospitalized because we test more, more people get really sick because there’s more infection out there.

RUHS Coronavirus/https://www.rivcoph.org/coronavirus
RUHS Coronavirus/https://www.rivcoph.org/coronavirus

What about the rest of the country? We’re seeing increasing cases in a number of hotspots around the country. The New York Times tracks where the virus is increasing and we’re seeing significant increases in several hotspots around the country.

NY Times map showing areas with increasing numbers of cases of COVID-19

The South was the first region to begin reopening after stay-at-home orders and they’re now the region with some of the most noticeable growth in the last two weeks with 10 states in the region on an increasing trajectory including Texas, Florida, Georgia, North Carolina, Louisiana, Tennessee, Alabama, South Carolina, Mississippi, Arkansas and Oklahoma. Overall, the most concerning regions in the country right now are Florida (reopening began May 4), Arizona (reopening began May 8), Texas (reopening began April 30) and Oklahoma (reopening began April 24). Florida had an 86% increase in new cases over one week and a doubling of their percent-positive rate to 11% in recent days. According to the Sun Sentinel, 75% of adult ICU beds in South Florida are now occupied. The state has had to walk back some of its reopening to address the rising cases there. Arizona has seen their percent-positive rate leap to 20% with an increase in new cases of 90% in a one week period. Oklahoma saw the biggest one week increase with a jump of 111% in new cases. Texas has seen similar increases in percent-positive rate (now at 10%) and new cases (up 86% in a week). More worrisomely, Texas has seen a 60% increase in new hospitalizations. NPR reports that Texas Children’s Hospital in Houston is now admitting adults with COVID-19 to help with the surge, this in spite of the fact that Houston is home to Texas Medical Center, the largest hospital in the world. The growth of the virus in Texas has led some regions within the state to begin mandating facial coverings and Governor Greg Abbot to implore the state’s residents to do so to help keep business open.

“Wearing a mask will help us to keep Texas open.”

Texas Governor Greg Abbott

States that reopened early are not the only states of concern right now and certainly other factors contribute to surges in a region like the recent protests and outbreaks at inpatient institutions. But there are some simple facts that seem to be lost on a significant percentage of Americans: SARS-CoV-2 is here, it’s a dangerous virus that can spread exponentially through an almost completely vulnerable population and no amount of hiding our collective heads in the sand about these previous two facts is going to make it go away. Perhaps the simplest and most effective thing Americans could do to prevent the spread would be to wear a mask when in indoor public spaces and outdoors when social distancing isn’t possible. If the majority of Americans wore a face covering under these circumstances, the spread of SARS-CoV-2 would be significantly limited and businesses would be much less at risk of new closures. As I discussed in a previous post, wearing a mask isn’t for your own protection. The science on masks shows us that if the majority of a population wears face coverings, we, the wearers, spread the virus to fewer people. Wearing a mask protects your neighbor, particularly the most vulnerable, it isn’t to protect you. Your neighbor wears a mask to protect you. If more of us do it, we protect more people. So let’s be neighborly and wear a mask to keep the economy open by stopping the exponential spread of COVID-19, which is starting to happen…again.

Here’s the video that nicely and understandably explains the math of exponential growth.

Categories
COVID-19

Why You Should Be Wearing a Mask, Starting Yesterday

Early on in the COVID-19 crisis, the US government, CDC and Public Health made an important error. US citizens were told that they should not wear masks. This mistake wasn’t completely without support in the scientific literature. Studies looking at mask-wearing as a way to prevent getting infected with a virus weren’t very convincing. Additionally, there’s evidence that people who wear masks may touch their faces more, a definite risk factor for becoming infected. Mainly though, in the early days we wanted to make sure that masks got to those who need them most–first responders and healthcare workers on the front lines.

It wasn’t very long after, however, before evidence started to mount that the US was looking at masks in the wrong way. Rather than focusing on the mask as protection for the wearer, studies were indicating that wearing a mask protects your neighbors from infection if you’re asymptomatic or presymptomatic. The virus is largely spread through respiratory droplets from coughing, sneezing, talking, singing or yelling. Wearing a mask, even one made from cloth, can be surprisingly efficient at trapping your infected droplets thereby preventing spread to others.

A widely sited recent study by De Kai, Guy-Philippe Goldstein, Alexey Morgunov, Vishal Nangalia, and Anna Rotkirch utilized a dynamic network-based compartmental model and individual agent-based modeling to study how masks can slow the spread of SARS-CoV-2. Compartmental models are a type of computational model that imitates how humans in different groups or “compartments” interact and similarly, agent based modeling follows the course of a disease through an individual or “agent” and tracks that agent’s interactions throughout the group or community. They’re fancy, they’re really cool and I have to admit they’re largely beyond me. This group of computational researchers, however, showed with these models that the spread of SARS-CoV-2 is significantly reduced when 80% of the population is compliant with mask-wearing in public by about day 50 of the pandemic. Their models also found that the response was nominal and basically unhelpful when only 50% of the public complies or if populations don’t start wearing masks in time. Similar to herd immunity from vaccination, in order to reap the benefits of masking and stop the spread of SARS-CoV-2, a significant majority of the population has to commit to complying in order to protect the larger community. When compliance slips we see viral outbreaks. If you’d like to better understand their methods, take a look at the author’s fascinating and compelling explanatory video.

To further examine the results of their modeling, the researchers compared them to real-world examples. They contrasted the response to the virus in countries and regions that adopted the practice of mask-wearing early and comprehensively with countries that don’t encourage or mandate universal mask-wearing. The correlations they found supporting their computational modeling were considerable. Countries and regions like Macau, Beijing, Shanghai, Hong Kong and Taiwan who made universal masking mandatory early saw a dramatic reduction of the disease from their peak and they generally avoided large-scale, strict lockdowns. On the other hand, countries with late or poor mask compliance demonstrated meager reduction of disease from peak even with the enactment of strict lockdowns.

De Kai, Guy-Philippe Goldstein, Alexey Morgunov, Vishal Nangalia, and Anna Rotkirch (2020) Universal Masking is Urgent in the COVID-19 Pandemic:
SEIR and Agent Based Models, Empirical Validation, Policy Recommendations/Used with permission

Similarly, the researchers looked at daily growth curves to show that countries with universal masking culture or early and comprehensive adoption of masking had significantly flatter disease curves than countries that don’t wear masks to any large degree.

De Kai, Guy-Philippe Goldstein, Alexey Morgunov, Vishal Nangalia, and Anna Rotkirch (2020) Universal Masking is Urgent in the COVID-19 Pandemic:
SEIR and Agent Based Models, Empirical Validation, Policy Recommendations/Used with permission

Finally, the researchers placed countries into a quadrant map showing percent reduction from peak on the x-axis and daily growth on the y-axis. Countries in the bottom right of the graph had the largest percent reduction from peak disease and the lowest daily growth–less spread, quick recovery. Countries in the top left quadrant have had the smallest reduction in disease from peak and the highest daily growth–more spread, slow recovery. The United States sits squarely in this quadrant but countries with universal mask wear sit alone in the best quadrant of the graph.

De Kai, Guy-Philippe Goldstein, Alexey Morgunov, Vishal Nangalia, and Anna Rotkirch (2020) Universal Masking is Urgent in the COVID-19 Pandemic:
SEIR and Agent Based Models, Empirical Validation, Policy Recommendations/Used with permission

The evidence for universal mask-wear is now decidedly compelling. We should all be wearing masks and we should start yesterday. So convincing is the science that on May 14, over 100 health experts wrote a letter imploring governments to mandate the wearing of cloth masks to stop the spread of SARS-CoV-2. While some states have taken this to heart, only 15 have actually passed laws mandating the wearing of masks in public. Most of those states are on the Eastern Seaboard. The science here is quite clear; wearing masks will significantly reduce viral spread. If enough people embrace the practice and we don’t wait until it’s too late, we can even stop the virus in its tracks. I think the greatest argument in favor or mask-wearing for those who oppose it on political or personal freedom grounds are the potential benefits for business. If we work to effectively quarantine our noses and mouths, we may not have to quarantine our bodies when this virus begins to surge again. And it will surge again. It’s what viruses do.

My family and I will be wearing our masks to protect you and your family. I’d be really grateful if you returned the favor.

I’d like to thank De Kai from the Hong Kong University of Science and Technology and the International Computer Science Institute at UC Berkley who graciously allowed me to use the three figures and graphs from his excellent article cited above. Please see these additional links provided by the author for more information on his study and the importance of universal masking.

Categories
COVID-19

Thoughts on COVID-19 May 19, 2020

Olgierd Rudak / CC BY (https://creativecommons.org/licenses/by/2.0)
  • Governor Newsom relaxed California’s requirements for accelerated reopening. The new criteria focus less on how many deaths a county or municipality have and more on the number of cases. The new criteria will allow for up to 25 cases per 100,000 members of the population and no more than an 8% positive test rate. This was a major sticking point for larger counties as the previous criteria required a county have no deaths before they could reopen. It’s estimated that 53 out of 58 counties could be eligible to accelerate their reopening under these new requirements.
  • Drug maker Moderna announced yesterday that its COVID-19 vaccine passed an important test. This early phase included 8 people and results have demonstrated that the vaccine was safe for them and that it produced a strong anti-COVID-19 antibody response. The company then studied those antibodies in the lab and found that they had a neutralizing effect on SARS-CoV-2 in vitro (scientific term for in a test tube). This is a standard approach and generally bodes well for an antibody’s ability to neutralize the virus in vivo (scientific term for in a living organism). Moderna’s approach to vaccines is different. Traditionally a vaccine contains inactivated virus or virus proteins which when injected into the body fool the immune system into thinking a real virus is present. The body then starts making antibodies to the harmless version of the virus. Once antibodies are present, they can mount an effective immune response when exposed to the real thing. Moderna instead uses something called an RNA vaccine. Instead of injecting virus bits or inactivated virus, they inject actual mRNA (genetic material) which codes for specific proteins on or in the virus itself (e.g. spike protein important for viral entry into a human cell). If Moderna had injected DNA into the the body there might be a risk of that DNA disrupting the body’s normal genetic code, but mRNA doesn’t incorporate into our genes, it only gets read to make protein. Once the vaccine mRNA is in the body actually starts creating the protein from the pathogen and expressing it on cell surfaces which is then recognized by memory cells allowing an immune response to a virus that the body has never actually seen. When a real virus invades, the body is ready for it and attacks it before it can do real damage. This type of vaccine has some advantages over traditional vaccines. They can be produced more quickly and more cheaply, they are less dangerous for patients since there’s no virus being used for the immune response and they can be scaled up quickly for mass vaccinations during a pandemic. Moderna plans to move on to their next phase of testing which will be an expansion to around 600 patients. Very good news indeed, but remember it’s still a long way to knowing for sure that this vaccine works and is safe.
  • More and more data is showing that we could very effectively control the virus if we quarantined our mouth and nose more effectively. If 80% of the population was fully compliant with wearing masks whenever in public, the data shows we could stop the spread of this virus. This, of course, could have major implications for reopening our society and getting businesses back up and running. For an excellent dive into the importance of masks take a look at this must-read.