Many Seeming Routes for Efficient Spread of COVID-19 in Santa Clara County, California

In spite of and even because of the stay-at-home, lockdown and other restrictions by health authorities in Santa Clara County, California (USA), there are many plausible routes for rapid efficient spread of the SARS-COV-2 virus presumed to cause COVID-19 in the county. Despite this, total deaths attributed to COVID-19 in the year 2020 remained remarkably low, comparable to expected deaths from pneumonia and influenza in prior years. This may of course change in the coming year.

Many probable routes of transmission are discussed and illustrated with pictures below.

Many Seeming Routes for Rapid Spread of the Disease

Santa Clara County, California (United States) continues to authorize many luxury apartment and other construction projects with teams of workers in close proximity five full days per week, after a brief 3-4 week shutdown in May. The lockdown herds large numbers of citizens into a few gigantic stores such as Safeway, Walmart, and Target, enabling what would seem like an efficient route for rapid spread of the disease. The lockdown also confines a large proportion of residents to large apartment complexes with many seemingly easy routes of transmission. “Essential” workers and others continue to use the county bus service which confines workers and others to an enclosed shared space for many minutes each day.

Ongoing Construction Projects

Santa Clara County continues to authorize many luxury apartment and other construction projects with teams of workers in close proximity five full days per week, after a brief 3-4 week shutdown in May — several weeks after the original lockdown order. On a personal note, a four-story luxury apartment building construction project with at least a dozen workers every weekday from about 7:30 am to 4:30 pm has continued across the street from my apartment building since the original lockdown order except for the brief shutdown in May.

Santa Clara County Allows Construction Projects Despite COVID-19
Over a Dozen Construction Workers Arriving for Work on Luxury Apartment Project in Santa Clara County, CA (August 6, 2020)
Construction Workers in Close Proximity (Santa Clara County, Dec. 7, 2020)

Herding Residents into Big Box Retail Stores

The lockdown continues to herd large numbers of citizens in Santa Clara County into a few gigantic stores such as Safeway, Walmart, and Target, enabling what would seem like an efficient route for rapid spread of the disease.

Safeway with Over Thirty Cars in Parking Lot (about 9:30 AM, December 7, 2020, Santa Clara County)

These giant “Big Box” retail stores have heavily used shared spaces and surfaces where one would expect the virus will rapidly spread. These include the entry/exit door areas, checkout counters, and refrigerators with popular products such as milk purchased by a large fraction of the customers and with door handles that all purchasers must use. These large stores often have hundreds of patrons in the store at the same time — all day, seven days per week.

Milk and other dairy products in a refrigerator with door handle that customers must use

In Santa Clara County, the lockdowns have closed or heavily curtailed restaurants, popular with the large population of single people and leading to a large increase in demand for microwave dinners often found in store refrigerators with door handles that must be used by the customers.

Microwave dinners in store refrigerator with door handle that customers must use

Several other specific scenarios exist for rapid efficient spread of the virus through these giant retail stores.

Bus Service for “Essential” Workers and Others

Santa Clara County also has a bus service, the VTA or Valley Transportation Authority, in widespread use with patrons, often “essential workers,” sharing an enclosed space and seats.

VTA Bus in Operation on December 7, 2020, Santa Clara County, California

Giant Apartment Complexes are Common in Santa Clara County

The lockdown shelter in place and stay at home orders confine “non-essential workers” to numerous generally large apartment complexes, often with hundreds of tenants, possibly thousands in some cases. In Mountain View, California — site of Google’s headquarters — about fifty-eight percent of residents (Town Charts, see Figure 5) are renters, most in large complexes. These complexes feature shared trash chutes/rooms, laundry rooms, hallways and lobbies with exterior doors and fire doors that must be opened by hand in most cases, providing many shared surfaces and spaces for spread of the virus.

Typical Trash Chute Room with Fire Door in Santa Clara County — Note Door Handle (December 7, 2020)
Typical Trash Room Interior with Trash Chute (Note Handle) in Santa Clara County (December 7, 2020)
Typical Laundry Room Door with Handle in Santa Clara County (December 7, 2020)

Note that fire regulations require closely spaced closed fire doors in the interior hallways — with handles or knobs that all residents must use to open the fire doors.

The large apartment complexes common in Santa Clara County provide numerous shared spaces where aerosol virus particles can collect and linger in the air as well as shared surfaces such as door handles that all residents must touch.

Gloves are not required. Gloves would have to be handled carefully and sterilized before and after each or nearly each use to avoid spreading the virus, something probably impractical and certainly currently NOT done by most residents.

In general, the apartment complex support staff cannot clean each door handle after each use. The shared support staff themselves are a high risk of both becoming infected and spreading the infection to other residents. Almost none have training or experience in bio-safety measures.

Conclusion

Despite hyperbolic headlines and reasonable expectations, deaths attributed to COVID-19 have remained remarkably low in 2020, although that may — of course — change. We will see if the usual winter surge in cases and deaths from respiratory illnesses subsides for COVID-19 or not. Prediction is notoriously difficult — especially about the future. As demonstrated above, this appears to have been in spite of rather than because of the stay-at-home and lockdown measures.

The reasons for this remarkably low death rate in Santa Clara County in 2020 remain unknown. Possible explanations include the bright sunny climate — among the most pleasant in the world, close long term past contact with China contributing to a high pre-existing immunity or resistance to SARS type coronaviruses in general, some genetic or cultural difference in Santa Clara County’s heavily Asian population (death rates in Japan and other Asian nations have been quite low compared to the United States or Europe if official figures are to be believed), better treatment of patients such as avoiding intubation, higher consumption of vitamin D by the health conscious residents, or some other cause.

(C) 2021 by John F. McGowan, Ph.D.

About Me

John F. McGowan, Ph.D. solves problems using mathematics and mathematical software, including developing gesture recognition for touch devices, video compression and speech recognition technologies. He has extensive experience developing software in C, C++, MATLAB, Python, Visual Basic and many other programming languages. He has been a Visiting Scholar at HP Labs developing computer vision algorithms and software for mobile devices. He has worked as a contractor at NASA Ames Research Center involved in the research and development of image and video processing algorithms and technology. He has published articles on the origin and evolution of life, the exploration of Mars (anticipating the discovery of methane on Mars), and cheap access to space. He has a Ph.D. in physics from the University of Illinois at Urbana-Champaign and a B.S. in physics from the California Institute of Technology (Caltech).