Los Angeles County Data: Stay at Home Health Orders are Working to Slow the Spread of COVID-19


LOS ANGELES – The Los Angeles County Department of Health Services (DHS) released today its COVID-19 Hospital Demand Modeling Projections showing that physical distancing is slowing the rate of COVID-19 transmission in the county. The projections indicate that if current levels of physical distancing are not maintained, there will be an exponential rapid increase in the rate of infection, severely hampering the ability of the hospital system to meet that demand.

The insights from this modeling effort in large part informed the County of Los Angeles Dept. of Public Health’s decision to extend the ‘Safer at Home’ order until May 15, 2020.

“Physical distancing has ‘flattened the curve’ by slowing the rate of transmission of the virus. Because of this, our healthcare system is able to meet the demand for treatment for COVID-19 patients, providing quality lifesaving services to all those who need them,” DHS Director Dr. Christina Ghaly said. “However, we need to remember that while, yes, transmission is slowing, we are still on a growth curve, and thus need to maintain the public health interventions in place. Physical distancing is the single biggest action we can take to continue to fight this virus. If we went back to life as normal today, by late summer the vast majority of Los Angeles County residents would likely have experienced infection with the virus, putting excessive strain on the healthcare system.”

The modeling team was tasked with taking available data and making the best possible predictions regarding the spread of COVID-19 in Los Angeles County and associated demand for hospital-based care including hospital beds, intensive care unit (ICU) beds, and ventilators. The team assessed the effectiveness of current physical distancing efforts in slowing the spread of COVID-19 and “flattening the curve.”

The predictive analysis which models the impending surge provides a depiction of the best- and worst-case scenarios for Los Angeles should physical distancing efforts continue and to what degree. The model projects that if we reverted to pre-order physical distancing behavior now, by August 1, 95.6% of Los Angeles County residents will likely have been infected over the course of the pandemic. Under this worst-case scenario, Los Angeles County would face an infection rate at such magnitude that the healthcare system would not be able to treat patients who need hospitalization, underscoring the need to continue to maintain current levels of physical distancing.

To learn more about LA County Department of Health Services, visit dhs.lacounty.gov.

The modeling presentation produced by LA County Department of Health Services can be found here.

About the Modeling Team

The modeling was completed under the guidance of DHS Director Dr. Christina Ghaly, in partnership with a multidisciplinary team of clinical, epidemiological, and statistical experts led by Roger J. Lewis, MD, PhD, the Chair of Emergency Medicine at Harbor-UCLA Medical Center in Torrance and an accomplished statistician.

The statistical modeling work was performed under the leadership of Dr. Roger Lewis by statisticians from Berry Consultants, LLC, Austin, Texas. Joseph Marion, PhD, Kert Viele, PhD, and Todd Graves, PhD supported the effort by performing all modeling of epidemic and healthcare resource data for Los Angeles County related to the COVID-19 epidemic.

In addition to Dr. Lewis, the modeling team also included Juliana Tolles, MD, MHS (Emergency Physician, Harbor-UCLA Medical Center), M. Claire Jarashow, PhD, MPH (Acting Director, Vaccine Preventable Disease Control and Chief, Epidemiology and Data, Acute Communicable Disease Control, Los Angeles County DPH), Fei Wu, PhD (Office of the Chief Information Officer, Los Angeles County CEO Office), and Frederic Schoenberg, PhD (Professor of Statistics, UCLA). Important insights and guidance were received from others, including personnel at the California Department of Public Health, as well as other modeling teams addressing the COVID-19 epidemic across the country.

Berry Consultants, LLC is a statistical consulting company specializing in the Bayesian approach to medical statistics; this approach changes the way research is done in healthcare. With top tier experts, Berry Consultants leverages innovative clinical trial design and analysis methods, setting a new standard for efficient trials that often operate faster than typical trials, thus potentially bringing life changing treatments, cures and other beneficial interventions to patients sooner than typical approaches.