The seasonal flu is more than just fever, cough, and sore throat. Many individuals, particularly older adults and young children, frequently find themselves hospitalized due to severe flu symptoms, as highlighted by a recent study.

Each year, over 100,000 people are hospitalized in the U.S. due to flu-related complications, and around 4,900 lose their lives. Vaccines that focus on the previous year’s most prevalent flu strains can significantly reduce the risk of serious illness or death.

A study published on Tuesday in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report emphasized the ongoing risks posed by seasonal flu, particularly for those who are unvaccinated.

“People of all ages, including those without any underlying health issues, still face hospitalization risks,” noted Dr. William Schaffner, a co-author of the study and a professor of infectious diseases at Vanderbilt University Medical Center, during an interview with YSL News. “The influenza virus is powerful; it can take a healthy individual and render them hospitalized in just 48 hours.”

Data from the CDC’s flu surveillance system covering the years from 2010 to 2023 indicates that individuals aged 65 and over experienced the highest rates of hospitalization, followed closely by children aged 4 and younger. Generally, these age groups are at a higher risk for infectious diseases.

The research, conducted by scientists from the CDC along with various health departments and universities, reviewed hospitalization data from several regions in the U.S. It is important to note that these findings may not represent the entire country.

Those who suffered severe cases of flu were often found to have pre-existing medical conditions. Among children, asthma, neurological disorders, and obesity were the most commonly associated conditions. In adults, prevalent conditions included hypertension, obesity, chronic metabolic illnesses, chronic lung diseases, and cardiovascular diseases, all of which are common in the United States.

With the onset of the COVID-19 pandemic, there was a noticeable drop in flu hospitalizations. Dr. Schaffner mentioned that strict social distancing and reduced interaction among children during school closures likely contributed to this decrease in flu transmission.

During the 2022-23 flu season, there were 64.4 hospitalizations per 100,000 people, a return to levels seen before the pandemic. However, this was still lower compared to the 2017-18 season, which recorded 102.9 hospitalizations per 100,000 people—the highest during the period studied. The report noted ongoing ICU admissions, need for medical ventilation, and in-hospital fatalities, indicating that “influenza remains a significant cause of serious illness and death.”

Higher hospitalization rates for flu were observed among Black individuals, Native Americans, and Alaska Natives, who also reported elevated rates of ICU admissions.

The findings suggested that lower vaccination rates within these communities may contribute to their increased hospitalization rates when compared to white individuals. The researchers noted that ongoing analysis of these trends is necessary to understand the reasons behind these disparities and to improve prevention efforts in communities of color.

Dr. Siobhan Wescott, the Dr. Susan and Susette La Flesche Professor of American Indian Health at the University of Nebraska Medical Center, remarked that the study uncovers troubling trends in various demographic groups that require further attention. She emphasized that misinformation and reluctance to receive vaccinations increase hospitalization rates.

“It’s important for us to consider these issues,” stated Wescott, who was not involved in the study. “We need to focus on improving vaccination rates and addressing comorbidities, particularly in culturally relevant ways for Indigenous populations.”

The study revealed a decrease in the use of antiviral treatments among patients, dropping from a high of 90.2% in the 2018-19 season to below 80% in 2022-23, with particularly notable declines among children. Antiviral medications like Tamiflu and Relenza can lessen the severity of illness and enhance patient outcomes in hospital settings. The reduction in medication use represents a “worrisome trend that signifies lost opportunities” to prevent complications linked to influenza, as highlighted in the study.

Among hospitalized adults aged 18 to 49, the likelihood of receiving seasonal flu vaccinations was notably low. Vaccination rates peaked at 31.1% during the 2014-15 season, but by the 2022-23 season, it had fallen to only 15.4%.

Patients who had received the flu vaccine had a significantly lower chance of requiring ICU admission and a 31% reduced risk of dying compared to those who were not vaccinated.

A recent CDC study indicated that the current flu vaccine might not be as effective compared to previous seasons, especially regarding the prior winter in the Southern Hemisphere. Nonetheless, it still offers protective benefits and decreases the risk of hospitalization by about 34%, according to the study.

Dr. Schaffner, one of the study’s authors, advised that the optimal time for vaccination is in October and November, when flu season begins. He encouraged anyone who has not yet made arrangements to get vaccinated without delay, emphasizing the urgency of the situation.

Influenza is expected to spread each fall and winter, alongside other respiratory illnesses such as COVID-19 and respiratory syncytial virus (RSV), as noted by Dr. Yvonne Maldonado, a professor of pediatrics, global health, and infectious diseases at Stanford Medicine. These illnesses can all lead to hospitalizations, but Vaccines can play a key role in helping prevent serious illness.

“Why not take the opportunity to safeguard yourself again?” she remarked to YSL News. “We wear helmets and obey traffic signals. Our goal is to focus on prevention. It’s one less concern to have.”

According to data from the CDC, the 2023-24 season saw a particularly alarming increase in flu-related deaths among children, with 199 fatalities, which correlated with a decrease in vaccination rates.

(This article has been updated with the latest information.)