As summer 2020 ended, U.S. hospitals filled with COVID-19 patients and health officials worried over a second health threat on the horizon - severe seasonal influenza.
The anticipated "twindemic" would cause hospitals to burst at their seams and overrun already over-burdened health care workers.
Health officials worried the existing pandemic would discourage the public from seeking seasonal influenza vaccinations.
However, the influenza season has persistently been subdued this year, maybe unlike any previous year in Missouri.
The state is normally nearing its flu activity peak at this time, said John Bos, Missouri Department of Health and Senior Services bureau chief for communicable disease and prevention.
"The why is a great question. I'm not certain it can be explained at this time," Bos said.
It's likely efforts to slow the spread of COVID-19 - reduced travel, social distancing, focuses on hygiene and mask-wearing - played roles, he said.
The 2020-21 flu season will be studied for a time to come, he said.
To date, Cole County only had 21 reported cases of the flu this season, according to data provided by the Cole County Health Department.
At the same time last year, the county had seen 1,316 cases of Influenza A and 2,086 cases of Influenza B. The entire flu season last year accounted for 1,721 cases of Influenza A and 2,292 of Influenza B in Cole County.
Health care providers distributed more flu vaccines in 2020 than in the past, but not enough to fully explain the drastic turnaround in the numbers. For example, St. Mary's Hospital provided about 5,000 flu shots in 2020. It had provided about 4,000 in 2019, according to data the hospital provided.
Data show only 24 laboratory-confirmed cases of the flu showed up in Missouri hospitals during the week ending Feb. 20. That was a far cry from 2019-20, when nearly 13,000 cases appeared in the state's hospitals. That season, which was late by any account, peaked about the first week of March, when about 14,000 cases showed up in hospitals.
The previous year, also a relatively late year, saw about 7,000 new cases during the week. It peaked about five weeks later.
Typically, flu season monitors designate Oct. 1 as the beginning of the season. The Missouri Hospital Association dashboard, which includes seasonal influenza data, indicates on Oct. 1, 2020, there were 73 new cases of "influenza-like illnesses" (or ILI) that arrived in emergency departments in the state, compared to 93 the year before.
On the same day, state emergency departments saw 314 new cases of COVID-19-like Illnesses (CLI).
A week later, on Oct. 8, 2020, Missouri had 76 new cases of ILI in hospital emergency departments. The year before, there were 107. The state reported 399 new cases of CLI in emergency departments on Oct. 8, 2020.
In 2020, ILI in emergency departments peaked Feb. 17 at 587 visits.
This year, influenza has been a flat line all season. It peaked Nov. 16 at 127 cases of ILI showing up in emergency rooms.
The most recent data show only 36 new cases were reported in the state Feb. 17.
"Missouri is consistent with the national trend," Bos said. "All states reported minimal activity for the flu this week."
Every other state in the nation is experiencing "sporadic" influenza activity at its worst. The Centers for Disease Control and Prevention posts a weekly page that - normally this time of year - paints a multi-colored map of the United States, with each state splashed in varying degrees of vibrant ominous yellow, orange or red, indicating influenza spread as low, moderate, high or very high outbreaks within each state.
But the entire map is green, indicating the sporadic nature of influenza spread.
The CDC website notes, "Seasonal influenza activity in the United States remains lower than usual for this time of year."
In Missouri, only one influenza-associated death has been reported this season, according to DHSS's weekly surveillance report.
As of the third week of February last year, Missouri had seen 29 deaths. Two flu outbreaks had been reported, and four schools had to close because of influenza. There were 64 deaths by the same time in 2019 and eight outbreaks with five school closings.
With the COVID-19 pandemic looming over the nation late this summer, there was a big effort to increase vaccinations for influenza as soon as the anticipated influenza strains were identified, Bos said.
Until data can be scrutinized, it's important to continue efforts to mitigate COVID-19, he said.
"If they do impact the transmission of flu," Bos said, "it's a positive."