The start of flu season this fall comes with a heightened concern about a "twindemic" — a surge of COVID-19 cases amid a severe flu season.

The fear is that emergency rooms and intensive care units would be stretched to capacity, as both diseases can cause respiratory complications such as pneumonia.

A twindemic is not inevitable, given COVID-19 safety measures and a mild flu season in the southern half of the globe.

Still, health officials are doubling down on efforts to get more Minnesotans vaccinated for influenza.

Typically, about half of the state population above the age of 6 months gets a flu vaccination, according to the Centers for Disease Control and Prevention.

The highest number of doses are given in October, according to state data, and most of the shots are given by the end of November. In the 2018-2019 season, only 15% of the 2.4 million vaccinations were administered after November.

With some people still working at home, workplace flu clinics might get canceled this year, just as many blood drives have been scratched, which has placed pressure on the blood supply.

People might also stay away from clinics for fear of catching COVID-19. Those concerns have led to a decrease in childhood vaccinations, such as measles, mumps and chickenpox.

Minnesota's health systems say they are taking safety precautions in all their facilities and they are avoiding walk-in clinics to control the number of patients in the building.

HealthPartners and M Health Fairview are also offering drive-through flu shots, much like the COVID-19 testing done for vehicle drivers and passengers.

"What we are hoping for is that we will see more people getting flu vaccines this year given that we don't have a vaccine for COVID-19," said Dr. Beth Averbeck, senior medical director for primary care at HealthPartners. "We hope to get enough people vaccinated to the extent that we can at least try to prevent one of the respiratory illnesses and reduce the overall burden."

Flu infections could get tamped down with the COVID-19 safety measures, including masks, social distancing, hand hygiene and staying home while sick.

"All those things work for influenza," said Dr. Tim Sielaff, chief medical officer at Allina Health. "So if we do all those things and we get really good vaccination rates we should be able to control influenza better than we have before."

Another hopeful sign that a twindemic is less likely comes from the flu season in the Southern Hemisphere, which runs from May to October.

"What they have seen in the Southern Hemisphere is very low flu activity," said Jennifer Heath, a public health nurse with the vaccine preventable disease section of the Minnesota Department of Health.

Health officials attribute the low flu numbers partly to COVID-19 safety measures and restrictions on air travel.

"We don't know what is going to happen here in the United States and what happens in the Southern Hemisphere is not always predictive of what we see," said Heath.

Minnesota flu seasons play out in different ways. Last year was relatively mild, with 153 flu-related deaths, but still more serious that the previous season, which had 88 deaths. Over the past six seasons, the most fatal was 2017-2018, which had 440 deaths. Flu seasons run from October through May.

Although deaths were relatively low last season, there were 4,146 hospitalizations, the second highest of the past six seasons.

Last season also started unusually with the "B" strain of the virus, which typically doesn't emerge until the end of the season. That strain particularly affects children and it resulted in 921 school outbreaks, peaking right before Christmas.

The "A" strain of the seasonal flu is the one that is causes global pandemics. Both strains have many variations, which is one reason why flu vaccines are only 40% to 60% effective, according to the CDC.

That's one reason why some people don't get the flu shot, but public health officials typically advise that even though vaccinations can't prevent all infections, it can reduce the severity of symptoms.

Minnesota health systems say that they have good supplies of the vaccine. Manufacturers are expected to produce up to 198 million doses, which would be a record setting amount and a 13% increase from last year, according to the CDC.

The Health Department has doubled the amount of free flu vaccines it is providing, with 400,000 doses available to underserved communities, communities of color and rural areas. They have flexibility this season to use some of the doses for other groups to broaden access, Heath said.

In preparation for COVID-19, many hospitals have taken steps to increase bed capacity if needed.

"We have plans that date back to March and April," said Sielaff. "We are prepared to increase capacity to significant levels if that is warranted by the number of patients who need care."

As the medical community has learned how to care for COVID-19 cases, the number of those needing hospitalization has dropped significantly since late May when there were 606 getting hospital-level care for the coronavirus.

On Thursday, there were 257 COVID-19 inpatients.

Even before COVID-19, severe cases of influenza had the potential to strain hospital resources.

"During particularly bad flu seasons it does tend to stress our hospital bed and ICU capacity, but not to the point where we are unable to care for patients," said Sielaff.

One other encouraging sign is that summer cases of the flu in the United States, although rare, are a fraction of what is typically seen.

Minnesota has had five confirmed flu cases since mid-May.

"This is not unusual and actually lower than we typically see," said Karen Martin, an infectious disease epidemiologist at the Health Department. "While having few cases of flu is good news, we know that flu is unpredictable and we continue our preparations for the season ahead."