Originally Published: 21 SEP 21 06:13 ET

By Jacqueline Howard, CNN

(CNN) -- They're a fall staple in most communities across the United States: flu shot clinics.

But this year many will offer something extra -- Covid-19 shots.

As the Delta variant spreads and uncertainty lingers around what the flu season could bring, joint vaccine clinics have emerged in cities and counties nationwide to offer a one-stop choice to receive either a Covid-19 vaccination, flu shot or both.

"I think many of us are concerned about the fact we didn't see much flu last year. Are we going to see convergence of a pandemic plus flu season at the same time, when we're already seeing a crunch in our healthcare facilities?" Dr. Robert Hopkins, chief of general internal medicine at the University of Arkansas for Medical Sciences and chair of the National Vaccine Advisory Committee, told CNN.

Last week, the University of Arkansas for Medical Sciences opened a new vaccine clinic in Little Rock to provide both Covid-19 and influenza vaccines to students, staff or anyone in the community.

"We're trying to, as much as we can, address the needs for both flu prevention and Covid-19 prevention, and as you well know Arkansas' vaccination rates for Covid are not where we'd like to see them by any means," Hopkins said.

"If somebody comes in wanting the flu vaccine and they haven't had a Covid vaccine then we can encourage them to get both, or vice-versa," he said. "If they come in wanting the Covid vaccine and they haven't had the flu vaccine and we can encourage them to do both, we potentially are going to have a greater impact on both disease prevention efforts."

Also last week, a joint Covid-19 and flu vaccination clinic popped up in Lumberton, North Carolina.

Robeson Community College hosted the clinic on Wednesday, in partnership with Walgreens, to administer Covid-19 shots and flu shots to students, faculty, staff and the general public.

The college has signed up with the White House and US Department of Education to be a "vaccine champion" by delivering vaccines to students and the community -- and, so far, helped to vaccinate more than 200 people against Covid-19 through clinics on its campus. Robeson County has some of the lowest vaccination rates in North Carolina, Melissa Singler, president of Robeson Community College, wrote in an email to CNN.

"We felt holding a joint vaccination clinic for both COVID-19 and the flu was the right thing to do," Singler wrote in the email, adding that the clinic is the first offered by the college for both the Covid-19 vaccine and the flu shot.

"Vaccinations are critical in the new school year to help us avoid interruptions," Singler wrote. "There has been an expectation that the flu would be worse this year than in year's past, however our county is at a critical stage with COVID-19 transmission rates being at record levels, so that has been our main focus, in preventing outbreaks and clusters."

In more cities and counties across the country, there have been talks about planning flu shot events alongside Covid-19 vaccine clinics to help get people vaccinated against both influenza and the coronavirus.

'Clinics are happening'

"This is a big area of concern for our health departments who remain worried about the conflation of the flu with the pandemic again -- and whether we should be doing flu and vaccine clinics together to try to get people protected as much as possible," Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials, told CNN.

The US Centers for Disease Control and Prevention and the American Academy of Pediatrics both have said people can receive their flu shots simultaneously with a Covid-19 vaccine.

"There's concern about how we're going to be able to cope with the flu season on top of the pandemic, especially for school-aged children," Freeman said.

"The thing about seasonal flu is you never know what you're going to get with the flu season. You never know what type of flu," Freeman said. "Is it going to be an especially harmful flu that impacts certain populations? The last thing we need is another harsh flu that could impact certain groups of the population, like the elderly or kids, differently."

To make vaccinations convenient for children, some schools have long served as sites for flu shot clinics -- and in many schools across the country, clinics have started work, Linda Mendonca, president of the National Association of School Nurses, told CNN.

"We always are preparing for flu season every year. So, school nurses are engaged in coordinating the school-located vaccine clinics in their school communities," Mendonca said, adding that joint clinics to administer flu and Covid-19 vaccines "make sense."

"We certainly promote vaccines as a way of decreasing risk from preventable disease or virus, such as the flu," Mendonca said. "Clinics are happening."

Still, it remains unclear whether the upcoming flu season could be particularly harsh -- or almost nonexistent, as it was last year.

What the flu season might bring

"It is well known that influenza is unpredictable. We do have some clues on what to expect each year based on what happens in the southern hemisphere and what has happened in other countries during the Covid-19 pandemic," Dr. Flor Munoz, a pediatric infectious disease specialist at Texas Children's Hospital, told CNN.

"I don't think we were very surprised to not see influenza activity last year, because that's exactly what happened in southern hemisphere countries," Munoz said. "There has been still very little influenza in the southern hemisphere this year. It was still another mild winter season in the southern hemisphere, where there wasn't typical high influenza activity. But what we are seeing in the United States is that there has been some low level activity starting towards the end of the summer, which is unusual."

Since there were relatively few flu cases last year, scientists at the University of Pittsburgh Graduate School of Public Health have predicted in a pre-print paper that there will be a "large compensatory" flu season this year. The paper, which has not published in a peer-reviewed journal, was posted to the server medrxiv.org last month.

A model based on previous flu seasons projects in the paper that there could be 102,000 additional hospitalizations this upcoming season due to flu illnesses, which corresponds to a 20% increase compared with the average number of hospitalizations in past flu seasons. The researchers predict some people may have waning immunity due to low levels of flu circulating last year.

"However, higher influenza vaccine uptake would reduce this projected increase in influenza," the researchers wrote in their paper.

'This year the situation could be dangerously different'

The American College of Emergency Physicians issued a statement on Thursday noting that there are "early signs" the coming flu season could be severe and recommending everyone eligible get vaccinated against Covid-19 and flu.

"Last year, more people staying home and covering their faces when they did go out kept flu numbers historically low, but this year the situation could be dangerously different," Dr. Mark Rosenberg, president of the American College of Emergency Physicians, said in the statement.

"Unfortunately, misinformation is rampant, and the risk of getting or spreading either virus increases as more people dismiss proven public health protocols," Rosenberg said. "We should be taking every precaution to protect ourselves and our loved ones from either virus. Getting vaccinated is one of the best ways to avoid the double whammy of flu and COVID."

Dr. David Cennimo, an infectious disease specialist at Rutgers New Jersey Medical School, said in a news release that a "twin-demic" of Covid-19 and flu is "very possible" this year.

"Based on what we are currently seeing for other respiratory infections, like respiratory syncytial virus, which is coming back with a vengeance, I expect we will see a resurgence of influenza at above-average levels this year," Cennimo said in the release.

"It's another reason why flu and COVID-19 vaccinations are so important. Although instances have been rare, you can contract COVID-19 and the flu simultaneously, which could result in a much worse condition. On the health care side, having both viruses circulating makes diagnosis difficult. If you contract the flu, you will have to quarantine and be tested to rule out COVID-19," he said.

"This highlights the importance of children under 12, who cannot yet receive the COVID-19 vaccine, receiving the flu vaccine. Vaccinated children are less at risk for the flu, whose symptoms can be confused with COVID-19 and cause possibly unnecessary school quarantines while awaiting a proper diagnosis."

Doctors recommend flu shot by Halloween

Pediatricians recommend that both adults and children 6 months and older receive their flu vaccinations by Halloween, regardless of what the flu season might look like.

"It's already available, so you can get vaccinated starting right now and ideally by end of October whenever possible," said Munoz, who was an author of the American Academy of Pediatrics' recommendations for the prevention and control of flu.

"It is important to have the option to prevent one of the infections that causes pneumonia -- similar to Covid -- especially in young children, because we still don't have the vaccine for Covid for that age group," Munoz said, adding that for unvaccinated people, there is the potential risk of being infected with both flu and the coronavirus.

"It seems that coinfection with Covid and other respiratory viruses, rhinovirus or RSV and Covid, for example, is common," Munoz said. "Having two viruses at the same time brings young children into the hospital because they can develop viral pneumonia or complications from these infections."