Coronavirus epidemic: How long can it go on?

Paul Sisson
San Diego Union-Tribune

So, here we are.

Pretty much nobody’s going to school, thousands are working from home, stores are struggling to stock their shelves and health officials are scrambling to respond to an unknown number of patients who will be taken ill with COVID-19.

Unprecedented actions taken since Wednesday to halt the spread of the coronavirus, from the total shutdown of K-12 school districts to significant curtailment of public gatherings, will surely have significant social and economic costs.

A downtown Bethesda, Md. restaurant is closed as Maryland Gov. Larry Hogan's executive order takes effect, closing bars, restaurants, gyms and movie theaters across the state in response to coronavirus, Monday, March 16, 2020.

Especially hard hit will be those in the service industry who may not get paid in the near future, or who must now try to find child care while they continue to fill essential jobs in health care, law enforcement, logistics and retail.

The question is, what does all of this swift action buy? How does it change the end game for the COVID-19 epidemic? How long will it take for the highly contagious virus to run its course? There are several factors at play.

Judging by the studies now coming out of China and other nations that have already taken such measures, infectious disease experts seem universally confident that having as many people stay as far away from each other as they can for several weeks in a row will make a significant difference.

But it’s tough, they add, to say how much novel coronavirus will still be circulating in the community come New Year’s Day, or even the Fourth of July, because we have not yet done enough testing to know with confidence how much is here already.

Dr. Robert “Chip” Schooley a UC San Diego infectious disease specialist and editor of the medical journal Clinical Infectious Diseases, noted that testing in the United States has been reserved mostly for those who have traveled to countries where COVID-19 outbreaks started months ago.

It will not be until significantly more people who have not traveled are tested that there will be a robust-enough measure of how broadly the disease has spread from person to person in communities, he said.

“We need to be in a situation where we have a larger number of people being tested for a wider variety of symptoms, and that will begin to fill in the blanks about how much virus is actually circulating,” Schooley said.

But that’s not to say, he added, that the data we do have indicates that the actions taken in America were an overreaction.

“Every day we see more and more of these dots that are lining up to make it clear that this virus is actually pretty widespread, and we really do need to be taking these actions,” Schooley said. “These are not carelessly thought out things that are being done just because we can do them. They’re being done because we need to do them.”

In the past seven days, the phrase “flatten the curve” moved from discussions among a select group of forward-thinking epidemiologists to the common lexicon, popping up on social media as results from ongoing studies in other places began to show the power of broad, unified action designed to prevent people from passing infections to each other.

Graphs showing the slow-growing number of cases over time in Singapore and South Korea, and a reversal of the out-of-control pattern in China, arrived just as America’s numbers spiked, reaching 1,280 by Wednesday and 2,174 by Saturday, according to Johns Hopkins University.

Many quickly learned that the commonality among these nations has been significant social distancing campaigns that are able to break chains of transmission by ruthlessly canceling public events, keeping kids home from school and being relentless about spotting new cases early and isolating the infected quickly, even if it means keeping them separate from their families.

While the pace and longevity of the epidemic is an open question, everyone already knows that reaching a state of herd immunity in communities across the nation will bring its true end. Herd immunity is a hard-earned state in which a large enough percentage of a population has already established immunity to a disease that it’s difficult to sustain long chains of person-to-person transmissions. When many of the people an infected person encounters are already immune, outbreaks tend to stay small.