5.01.2020

Two Years

The coronavirus pandemic has drastically altered the planet since first appearing in late 2019, infecting more than 3 million and resulting in the deaths of at least 230,000 people. As some parts of the world ease stay-at-home and lockdown orders, a new report says the pandemic could last up to two years.

The report, put together by the Center for Infectious Disease Research and Policy at the University of Minnesota, notes the similarities between COVID-19 and influenza pandemics, including both having asymptomatic cases and the global population having "little to no pre-existing immunity," which results in "worldwide susceptibility."
Though there are differences between SARS-CoV-2 and influenza, the researchers gleaned from past pandemics that the length "will likely be 18 to 24 months, as herd immunity gradually develops in the human population."

"This will take time, since limited serosurveillance data available to date suggest that a relatively small fraction of the population has been infected and infection rates likely vary substantially by geographic area," the researchers added. "Given the transmissibility of SARS-CoV-2, 60 [percent] to 70 [percent] of the population may need to be immune to reach a critical threshold of herd immunity to halt the pandemic."

The researchers also warned that control measures and other factors could impact the length and duration of different waves of COVID-19 cases.
Three different scenarios were laid out by the researchers:
  • The first wave of cases is "followed by a series of repetitive smaller waves that occur through the summer and then consistently over a 1- to 2-year period, gradually diminishing sometime in 2021." The researchers noted this could vary based on geographies and mitigation measures put in place by public health officials and lawmakers. 
  • The first wave is followed by a "larger wave in the fall or winter," with one or more subsequent waves in 2021, similar to the 1918-1919 influenza pandemic that resulted in an estimated 500 million cases and 50 million deaths worldwide.
  • The first wave is followed by a "'slow burn' of ongoing transmission and case occurrence, but without a clear wave pattern," also influenced by geographies and mitigation measures.
"Whichever scenario the pandemic follows (assuming at least some level of ongoing mitigation measures), we must be prepared for at least another 18 to 24 months of significant COVID-19 activity, with hot spots popping up periodically in diverse geographic areas," the researchers concluded. "As the pandemic wanes, it is likely that SARS-CoV-2 will continue to circulate in the human population and will synchronize to a seasonal pattern with diminished severity over time, as with other less pathogenic coronaviruses, such as the betacoronaviruses OC43 and HKU1, past pandemic influenza viruses have done."