April 04, 2022
Since the beginning of the COVID-19 pandemic, simulation models have been trying to predict the trajectory of the coronavirus. Early on, there was hope that the spread of the virus could be brought under control within a few weeks. More than two years later, it is clear that we will be dealing with COVID-19 for the foreseeable future.
Public officials have grappled with the appropriate time to lift – or reimplement – public health restrictions throughout the pandemic. After the omicron surge last winter, most restrictions have been curtailed, giving people hope for a return to pre-pandemic life.
But returning to a pre-pandemic lifestyle will come at a cost, according to a simulation model that projected the future of the pandemic in every state. It suggests there is no "magic moment" to lift restrictions, like mask mandates and social distancing guidelines, and return to pre-pandemic life.
Rather, any decision about lifting restrictions must come with a risk-benefit analysis, the scientists who designed the model say. And the biggest question will always be how much death is considered an "acceptable" trade-off to return to a life free of COVID-19 restrictions.
"Arguments to remove restrictions must explicitly make the case for lifting restrictions within a cost-benefit framework examining the cost of restrictions versus the cost of COVID-19 mortality," said researcher Jade (Yingying) Xiao, a doctorate student at Georgia Tech.
"At the same time, those who favor maintaining restrictions must recognize that 'just a little longer' will not suffice."
The model was based on the current pace of vaccinations and took into consideration different dates for lifting mandates. Relaxing masking mandates and other restrictions led to some "rebound" in COVID-19-related deaths, researchers found. But delaying the date of lifting mandates did little to lessen that eventual rise.
"The inevitable rebound in mortality was directly attributable to the omicron variant — when we repeated the analysis, assuming the infectivity of the previous alpha and delta variants, the model did not project such rising mortality after relaxing mask mandates," said Benjamin P. Linas, a professor of medicine at Boston University School of Medicine.
The degree of immunity in a community at the time mandates are lifted is one of the strongest predictors of the level of a surge in COVID-19 deaths, researchers found. Communities with a high percentage of residents who are vaccinated or have gained immunity through a prior infection are likely to have lower death rates.
"A difficult trade-off lies on the horizon," said researcher Jagpreet Chhatwal, director of Massachusetts General Hospital's Institute for Technology Assessment.
"While there is ample evidence in our analysis that a March 2022 lifting date leads to rebound mortality in many states, the simulation also suggests that with the omicron variant, whenever states do remove mandates, they will face the same difficult choice between increased COVID-19 mortality and the freedoms of returning to a pre-pandemic norm.
"The one intervention that can mitigate this impossible choice is ongoing COVID-19 vaccination with boosters," Chhatwal added.
The researchers added that if a less transmissible viral strain were to become more dominant, the rebound of infections and death would be substantially lower. This would allow public officials to more safely remove restrictions.
"Policy makers should consider the findings of this analysis as they monitor their state’s progress during the COVID-19 pandemic, project a suitable time to end restrictions, begin to discuss the conditions that must be met before declaring the pandemic over, and keep the public informed by making public health plans both safe and explicit," the researchers wrote in their report.
The research was conducted by scientists at Massachusetts General Hospital, Boston Medical Center and Georgia Tech.
According to the U.S. Centers for Disease Control and Prevention, the number of newly reported COVID-19 deaths will likely decrease over the next month, with 1,300 to 3,600 new deaths likely reported in the week ending April 23. That would the bring COVID-19 death toll in the U.S. to at least 986,000.
Many researchers say the coronavirus will eventually become endemic. Diseases become endemic when they are consistently present in a certain geographic area but relatively predictable in terms of their potential to spread, according to the CDC.
The viruses that cause influenza and the common cold are endemic. So is malaria in the tropics. But even when a disease is endemic, it can lead to life-threatening infections and death. The flu caused anywhere from 12,000 to 52,000 deaths each year from 2010 to 2020.
Dr. Stuart Ray, an infectious diseases expert at Johns Hopkins Medicine, previously told the Washington Post, "Endemic does not mean not harmful. It just means relatively stable and predictable."