Time to Rethink Predicting Pandemic Infection Rates?

Forecasting cannot foresee COVID-19 infection rates peaking or plateauing.
American Institute of Physics (AIP)

Newswise — WASHINGTON, November 24, 2020 -- During the first months of the COVID-19 pandemic, Joseph Lee McCauley, a physics professor at the University of Houston, was watching the daily data for six countries and wondered if infections were really growing exponentially. By extracting the doubling times from the data, he became convinced they were.

Doubling times and exponential growth go hand in hand, so it became clear to him that modeling based on past infections is impossible, because the rate changes unforeseeably from day to day due to social distancing and lockdown efforts. And the rate changes differ for each country based on the extent of their social distancing.

In AIP Advances, from AIP Publishing, McCauley explains how he combined math in the form of Tchebychev’s inequality with a statistical ensemble to understand how macroscopic exponential growth with different daily rates arise from person-to-person disease infection.

“Discretized ordinary chemical kinetic equations applied to infected, uninfected, and recovered parts of the population allowed me to organize the data, so I could separate the effects of social distancing and recoveries within daily infection rates,” McCauley said.

Plateauing without peaking occurs if the recovery rate is too low, and the U.S., U.K., and Sweden fall into that category. Equations cannot be iterated to look into the future, because tomorrow’s rate is unknown until it unfolds.

“Modelers tend to misapply the chemical kinetic equations as SIR (Susceptible, Infectious, or Recovered) or SEIR (Susceptible, Exposed, Infectious, or Recovered) models, because they are trying to generate future rates from past rates,” McCauley said. “But the past doesn’t allow you to use equations to predict the future in a pandemic, because social distancing changes the rates daily.”

McCauley discovered he could make a forecast within five seconds via hand calculator that is as good as any computer model by simply using infection rates for today and yesterday.

“Lockdowns and social distancing work,” said McCauley. “Compare Austria, Germany, Taiwan, Denmark, Finland, and several other countries that peaked in early April, with the U.S., U.K., Sweden, and others with no lockdown or half-hearted lockdowns -- they’ve never even plateaued, much less peaked.”

He stresses that forecasting cannot foresee peaking or even plateauing. Plateauing does not imply peaking, and if peaking occurs, there is nothing in the data to show when it will happen. It happens when the recovery rate is greater than the rate of new infections.

“Social distancing and lockdowns reduce the infection rate but can’t cause peaking,” McCauley said. “Social distancing and recoveries are two separate terms within the daily kinetic rate equations.”

The implication of this work is that research money could be better spent than on expensive epidemic modeling.

“Politicians should know enough arithmetic to be given instruction on the implications,” McCauley said. “The effect of lockdowns and social distancing show up in the observed doubling times, and there is also a predicted doubling time based on two days, which serves as a good forecast of the future.”


The article, "Pandemic infection rates are deterministic but cannot be modeled," is authored by Joseph Lee McCauley. The article will appear in AIP Advances on Nov. 24, 2020 (DOI: 10.1063/5.0015303). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0015303.


AIP Advances is an open access journal publishing in all areas of physical sciences—applied, theoretical, and experimental. The inclusive scope of AIP Advances makes it an essential outlet for scientists across the physical sciences. See https://aip.scitation.org/journal/adv.



Filters close

Showing results

110 of 4573
Released: 15-Jan-2021 5:40 PM EST
Research Links Social Isolation to COVID-19 Protocol Resistance
Humboldt State University

As health officials continue to implore the public to wear masks and practice social distancing, recent research by Humboldt State University Psychology Professor Amber Gaffney provides key insights into connections between social isolation, conspiratorial thinking, and resistance to COVID-19 protocols.

Newswise: Rapid blood test identifies COVID-19 patients at high risk of severe disease
Released: 15-Jan-2021 5:35 PM EST
Rapid blood test identifies COVID-19 patients at high risk of severe disease
Washington University in St. Louis

Scientists at Washington University School of Medicine in St. Louis have shown that a relatively simple and rapid blood test can predict which patients with COVID-19 are at highest risk of severe complications or death. The blood test measures levels of mitochondrial DNA, which normally resides inside the energy factories of cells. Mitochondrial DNA spilling out of cells and into the bloodstream is a sign that a particular type of violent cell death is taking place in the body.

Released: 15-Jan-2021 2:55 PM EST
COVID-19 deaths really are different. But best practices for ICU care should still apply, studies suggest.
Michigan Medicine - University of Michigan

COVID-19 deaths are indeed different from other lung failure deaths, according to two recent studies, with 56% of COVID-19 patients dying primarily from the lung damage caused by the virus, compared with 22% of those whose lungs fail due to other causes. But, the researchers conclude, the kind of care needed to help sustain people through the worst cases of all forms of lung failure is highly similar, and just needs to be fine-tuned.

Released: 15-Jan-2021 2:50 PM EST
45% of adults over 65 lack online medical accounts that could help them sign up for COVID-19 vaccinations
Michigan Medicine - University of Michigan

As the vaccination of older adults against COVID-19 begins across the country, new poll data suggests that many of them don’t yet have access to the “patient portal” online systems that could make it much easier for them to schedule a vaccination appointment. In all, 45% of adults aged 65 to 80 had not set up an account with their health provider’s portal system.

Released: 15-Jan-2021 1:30 PM EST
New England Journal of Medicine publishes COVID-19 treatment trial results
University of Texas at San Antonio

A clinical trial involving COVID-19 patients hospitalized at UT Health San Antonio and University Health, among roughly 100 sites globally, found that a combination of the drugs baricitinib and remdesivir reduced time to recovery, according to results published Dec. 11 in the New England Journal of Medicine.

Released: 15-Jan-2021 12:40 PM EST
DNA test can quickly identify pneumonia in patients with severe COVID-19, aiding faster treatment
University of Cambridge

Researchers have developed a DNA test to quickly identify secondary infections in COVID-19 patients, who have double the risk of developing pneumonia while on ventilation than non-COVID-19 patients.

Released: 15-Jan-2021 12:30 PM EST
Fight CRC To Present Research Findings on The Impact of COVID-19 on the Colorectal Cancer Community at 2021 GI ASCO
Fight Colorectal Cancer

Fight Colorectal Cancer presents abstract at Gastrointestinal Cancer Symposium highlighting the need to address the barriers and opportunities for care within the colorectal cancer community during the COVID-19 pandemic

Released: 15-Jan-2021 12:25 PM EST
Technion to Award Honorary Doctorate to Pfizer CEO Dr. Albert Bourla
American Technion Society

Israel's Technion will award an honorary doctorate to Pfizer CEO and Chairman Dr. Albert Bourla, for leading the development of the novel vaccine against SARS-CoV-2, the virus that causes COVID-19. The honorary doctorate will be conferred at the Technion Board of Governors meeting in November 2021.

Released: 15-Jan-2021 11:30 AM EST
UW researchers develop tool to equitably distribute limited vaccines
University of Wisconsin-Madison

Researchers at the University of Wisconsin School of Medicine and Public Health and UW Health have developed a tool that incorporates a person’s age and socioeconomic status to prioritize vaccine distribution among people who otherwise share similar risks due to their jobs.

Showing results

110 of 4573