Hospital epidemiologists warn that rising vaccine hesitancy and lagging immunizations may heighten clinical burdens as seasonal virus transmission nears.
RT’s Three Key Takeaways:
- Declining Immunization Rates: Less than 44% of people in the US received a flu shot during the 2025-2026 season, down from 52% in 2021, according to the CDC.
- Severe Inpatient Burden: Influenza resulted in roughly 710,000 hospitalizations and 45,000 deaths across the US during the 2024-2025 season, highlighting the clinical importance of timely fall vaccination.
- Emerging Vaccine Platforms: The Food and Drug Administration (FDA) approved the first mRNA influenza vaccine in August 2026, providing a potential tool to better match circulating viral strains in future cycles.
Whether the coming respiratory virus season proves mild or severe could depend significantly on community vaccination numbers rather than viral mutations alone, according to infectious disease specialists at Cedars-Sinai.
“As we get further away from the COVID-19 pandemic, we’ve seen an increase in vaccine hesitancy, and this flu season could be much worse if too few people get vaccinated,” said Michael Ben-Aderet, MD, medical director of hospital epidemiology at Huntington Health and associate director of hospital epidemiology at Cedars-Sinai Medical Center.
According to data from the Centers for Disease Control and Prevention (CDC), influenza vaccination coverage across the US dropped from an estimated 52% in 2021 to less than 44% during the 2025-2026 flu season.
This drop in uptake arrives after a notable clinical toll in recent years. CDC estimates indicate that the influenza virus caused approximately 45,000 deaths and 710,000 hospitalizations in the US throughout the 2024-2025 season, demonstrating the capacity of the pathogen to place immense strain on inpatient and critical care healthcare teams.
“The flu shot remains the most powerful tool available to help prevent serious illness caused by the influenza virus,” said Ben-Aderet, medical director of hospital epidemiology at Huntington Health and associate director of hospital epidemiology at Cedars-Sinai Medical Center, in a news release. “I urge everyone eligible to receive the vaccine to get it.”
Timing and Clinical Recommendations
Physician organizations such as the American Medical Association recommend annual influenza immunization for eligible adults and children older than 6 months, according to Cedars-Sinai. Healthcare professionals note that September and October represent an optimal vaccination window before community viral spread typically escalates in November or December. The human body requires approximately two weeks following vaccination to mount an adequate protective immune response, according to the health system.
For adults aged 65 and older, clinicians advise administering a high-dose flu vaccine when available, as vaccine-induced immune responsiveness tends to decline with advancing age.
Advancements in Vaccine Technology
The upcoming respiratory illness season also marks a transition point for influenza immunization technology. The Food and Drug Administration (FDA) approved the first mRNA flu shot in early August 2026, according to Cedars-Sinai.
Vaccines produced using mRNA platforms can be manufactured and updated more rapidly than conventional egg-based formulations, which may enable closer antigenic matches if circulating viral strains mutate during the season. However, it remains uncertain when the new mRNA shot will become widely available to healthcare providers or which specific patient populations will be eligible for its initial rollout.
Inpatient Escalation and Antiviral Timing
Influenza transmission typically presents with fever, body aches, cough, sore throat, fatigue, headaches, and nasal congestion, while pediatric presentations frequently involve gastrointestinal symptoms like vomiting and diarrhea. Individuals infected with influenza can transmit the virus one day prior to symptom development and up to five to seven days after symptom onset, according to Cedars-Sinai clinical guidance.
While uncomplicated infections in low-risk individuals can often be managed through supportive care, hydration, and fever reducers, antiviral medications such as oseltamivir (Tamiflu) should be initiated within two days of symptom onset to maximize clinical efficacy among high-risk demographics, including immunocompromised individuals, older adults, and patients with underlying chronic cardiopulmonary disorders.
Healthcare providers also advise immediate in-person evaluation or urgent care referral for patients presenting with high fever, respiratory distress, persistent fluid intolerance, and unimproving clinical trajectories to prevent acute respiratory decline and minimize critical care admissions.
