The 2025 Flu Season: Overview of Severity and Emerging Respiratory Risks

Following a delayed onset, flu activity surged, resulting in a sharp rise in outpatient visits and hospital strain. According to the CDC’s latest estimates, between 47 million and 82 million flu illnesses occurred, leading to 21 million to 37 million medical visits, 610,000 to 1.3 million hospitalizations, and 27,000 to 130,000 flu-related deaths during the 2024–2025 season ^[1].

In parallel, COVID-19 continues to circulate, with new variants leading to localized outbreaks. Though overall cases have declined, older adults and immunocompromised individuals remain at higher risk for severe outcomes ^[2,3].

RSV also heavily impacted healthcare systems, especially within pediatric facilities. This season, the highest RSV-associated hospitalization rate rose to 3.8 hospital admissions per 100,000 people, slightly lower than the previous season’s peak of 4.3 per 100,000. These trends highlight the ongoing burden of RSV on pediatric health care facilities [4].

As of early July 2025, the CDC reports that respiratory virus activity remains low nationally, which is typical during summer months. However, preparations are underway for the 2025-2026 flu season. Based on the World Health Organization’s recommendations, the FDA has selected updated influenza strains for the 2025-2026 vaccine. Public health officials anticipate a gradual increase in flu activity beginning in October, with a potential seasonal peak between December and February ^[1,2].

COVID-19 and RSV activity remains at baseline levels, but both viruses are expected to follow seasonal patterns similar to previous years. Older adults and individuals with underlying health conditions should consult with healthcare providers about updated COVID-19 booster recommendations and the availability of RSV immunization ^[2-4].

In light of current global trends and the severity of the 2024-2025 flu season, healthcare organizations and clinicians should proactively review vaccination protocols, resource planning, and staffing models to ensure readiness for a potentially high-impact respiratory virus season.

As flu, COVID-19, and RSV activity begin to decline, other respiratory viruses have emerged, raising additional concerns for healthcare systems.

Avian Influenza (Bird Flu)

Across the U.S., the H5N1 strain of avian influenza has been detected in wild bird populations, poultry farms, dairy farms, and more. While human infections remain minimal, the CDC advises healthcare providers to test hospitalized flu patients for potential exposure to avian influenza in order to prevent further spread ^[5,6].

Measles Outbreak

Measles activity has surged across the United States in 2025, with more than 1,200 confirmed cases reported in 34 jurisdictions as of June. Texas remains the most affected, accounting for more than half of all cases and two of three measles-related deaths this year ^[7-10].

The CDC attributes the outbreak to declining MMR (measles, mumps, rubella) vaccination coverage and emphasizes the importance of routine childhood immunizations. States such as Maryland, California, and Connecticut have also begun piloting wastewater surveillance as an early detection tool for measles outbreaks ^[9].

Healthcare professionals are urged to remain vigilant, particularly in areas with low vaccination rates. The CDC recommends immediate isolation of suspected measles cases in airborne infection isolation rooms (AIIRs), where available, and the use of N95 or higher-level respirators and full PPE for clinical staff ^[12,13].

The CDC continues to recommend infection control and prevention measures to help reduce the spread of respiratory illnesses. Healthcare providers are encouraged to maintain hygiene protocols, optimize ventilation in patient care areas, and use appropriate personal protective equipment (PPE) in high-risk settings ^[11].

The use of high-quality protective equipment remains important, particularly for healthcare workers treating patients with respiratory illnesses. HALYARD* N95 Particulate Filter Respirators and Surgical Masks, which are NIOSH-approved, provide protection in flu-related environments. Their four-layer construction and flat-fold pouch style offer breathable and effective coverage for extended wear.

To mitigate the spread of avian influenza (H5N1), the CDC advises avoiding direct contact with wild birds and ensuring poultry is properly handled. Use personal protective equipment when handling poultry and promptly report any sick or dead birds to local or state health departments.

Measles is highly contagious and spreads through respiratory droplets when an infected person coughs or sneezes. The CDC reports that up to 90% of unvaccinated individuals who come into close contact with an infected person will also contract the virus. In healthcare settings, it is crucial for professionals to implement rigorous infection control measures to reduce the risk of transmission. The CDC recommends the use of PPE, including N95 or higher-level respirators, and airborne precautions for patients with suspected or confirmed measles, which involves promptly isolating them in an airborne infection isolation room (AIIR) if available ^[12,13].

Continued monitoring of emerging concerns, adherence to infection prevention measures, and resource management will remain priorities in the evolving public health landscape.

1. Centers for Disease Control and Prevention (CDC). (2025). Weekly U.S. Influenza Surveillance Report: 2024–2025 Influenza Season Week 24. https://www.cdc.gov/fluview/surveillance/2025-week-24.html
2. Centers for Disease Control and Prevention (CDC). (2025). Respiratory Viruses Surveillance Data. https://www.cdc.gov/respiratory-viruses/data/activity-levels.html
3. Centers for Disease Control and Prevention (CDC). (2025). COVID-19. https://www.cdc.gov/covid/index.html
4. Centers for Disease Control and Prevention (CDC). (2025). Respiratory Syncytial Virus (RSV) — Burden Estimates. https://www.cdc.gov/rsv/php/surveillance/burden-estimates.html
5. Centers for Disease Control and Prevention (CDC). (2025). Avian Influenza (Bird Flu). https://www.cdc.gov/bird-flu/index.html
6. Centers for Disease Control and Prevention (CDC). (2025). Health Alert Network Advisory for Avian Influenza A(H5N1). https://www.cdc.gov/han/index.html
7. Centers for Disease Control and Prevention (CDC). (2025). Measles: About Measles. https://www.cdc.gov/measles/about/index.html
8. Centers for Disease Control and Prevention (CDC). (2025). Measles Data & Research. https://www.cdc.gov/measles/data-research/index.html
9. Centers for Disease Control and Prevention (CDC). (2025). Measles Public Health Guidance. https://www.cdc.gov/measles/php/guidance/index.html
10. Centers for Disease Control and Prevention (CDC). (2025). Health Alert Network Advisory for Texas Measles Outbreak. https://www.cdc.gov/han/2025/han00522.html
11. Centers for Disease Control and Prevention (CDC). (2025). Infection Prevention and Control. https://www.cdc.gov/infectioncontrol/index.html
12. Centers for Disease Control and Prevention (CDC). (2025). Causes and Transmission of Measles. https://www.cdc.gov/measles/causes/index.html
13. Centers for Disease Control and Prevention (CDC). (2025). Infection Control: Measles in Healthcare Settings. https://www.cdc.gov/infection-control/hcp/measles/index.html