Pasadena, CA - October 12: Allissa Sanchez, LVN, gives her patient a vaccine during a flu and COVID-19 vaccination clinic at Kaiser Permanente Pasadena on Thursday, Oct. 12, 2023, in Pasadena, CA. (Francine Orr / Los Angeles Times via Getty Images)
CNN  — 

The first signs of respiratory virus season are just starting to show in the United States, but experts stress the importance of getting vaccinated now to stay healthy through the winter and reduce strain on the health care system.

Forecasts from the US Centers for Disease Control and Prevention suggest that this respiratory disease season will be similar to last year — which saw hospitals more full than at any other point in the pandemic — and worse than pre-pandemic years once again.

At the peak of the respiratory virus season, there could be between 15 and 25 new weekly hospitalizations for every 100,000 people in the US, according to the analysis. Covid-19 will probably account for half of those new hospitalizations, with flu and respiratory syncytial virus (RSV) combined accounting for the other half.

“With the addition of a third virus (COVID-19) that can cause severe disease, even an average respiratory season can place significant strain on our healthcare system,” the CDC wrote in a summary about the outlook.

For now, respiratory virus levels are relatively low in the US overall.

In the first half of October, combined hospitalization rates for Covid-19, flu and RSV were less than half of what they were at the same time last year, CDC data shows.

Covid-19 hospitalizations have been ticking down for about a month. There were about 16,000 new admissions in the second week of October, which will likely hold relatively steady over the next several weeks, CDC ensemble forecasts suggest.

The CDC also considers flu activity to be low currently, but some regions have seen slight increases. About 2% of outpatient health care visits were due to respiratory illness that included fever plus a cough or sore throat during the second week of October. That’s still below baseline level — but it’s already higher than it was at this point in any season since 2010, excluding last year, according to CDC data.

But it won’t stay that way for long, and experts say that vaccinations will play a critical role in keeping people safe and healthy.

“There are lots of reasons to think about whether there will be an even greater demand on the health care system than there was last year or the year before that,” said Nancy Foster, vice president for Quality and Patient Safety Policy at the American Hospital Association.

“Our number one ask is that people get their vaccines, and now’s the time. It’s been shown in good studies to be the number one thing that keeps patients from either getting the disease — or if they do get it, from getting as sick as they might and needing to come into the hospital.”

This is the first year that the US has vaccines available to protect against all three major respiratory viruses. Everyone ages 6 months and older should get the updated Covid-19 vaccine and this season’s flu vaccine, and the RSV vaccine is recommended for certain groups particularly at risk for severe disease, including infants and some older adults.

The CDC says it’s ideal to get the flu vaccine before the end of October — and flu, Covid-19 and RSV vaccines may be given at the same visit.

“Even with the end of the Covid-19 (public health emergency), our nation is in its strongest position yet to fight the three viruses responsible for the majority of fall and winter hospitalizations — flu, COVID-19, and RSV,” a spokesperson from the US Department of Health and Human Services said in a statement to CNN.

“In addition, HHS has been in constant communication with public health departments, providers, stakeholders, and medical associations for months — through webinars, stakeholder engagement, news appearances, and more — on the importance of vaccination this fall and winter respiratory virus season, when cases are expected to rise, as they do annually.”

As of Friday, nearly 12 million people have gotten the new Covid-19 vaccine since they were authorized last month, according to HHS. That’s millions more than the week prior, but still less than 4% of the US population.

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Vaccination uptake is a key uncertainty in the CDC’s forecasts for this respiratory virus season, Dylan George, director of the CDC’s Center for Forecasting and Outbreak Analytics, told CNN. That uncertainty remains, and the “overall assessment is unchanged, namely that COVID-19 will still likely add significant hospitalization burden this season relative to pre-pandemic years,” he said.

Hospitals always plan and prepare for respiratory virus season, but it becomes more important as respiratory viruses compound amid a system that’s strained for other reasons, too, said Dr. Kedar Mate, president and chief executive officer at the Institute for Healthcare Improvement.

“Emergency rooms are already bursting at the seams. Add to that the respiratory season that’s coming in the next couple of months, and we’ve got a recipe here for a very challenging winter for our hospitals,” he said.

“That’s why getting ahead of this right now with better primary prevention — by getting folks to consider the vaccine — will go a long way to both helping every person individually not have to come into the hospital, but will also help our health systems give the best possible care to the people that need it most.”