Flu, RSV, COVID-19, and More: Updates on the 2025 Respiratory Virus Landscape

As respiratory virus season continues, cases of norovirus, respiratory syncytial virus (RSV), influenza, and COVID-19 are rising across the country, resulting in hospitalizations, school closures, and other disruptions. In addition, recent reports of a tuberculosis (TB) outbreak and the lingering uncertainties around H5N1 avian influenza highlight the importance of staying informed on emerging public health concerns.¹

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The surge in viral cases is not uncommon or a surprise to health care providers. Every year during the colder winter months, cases of these viruses surge due to more time spent indoors with others. In previous years, the crossover of COVID-19, influenza, and RSV cases was referred to as a “tripledemic.” With the additional increased cases of norovirus, the media has labeled it the “quad-demic.”^1,2

“This is not new,” said Asha Shah, MD, director of infectious diseases and epidemiologist at Stamford Hospital, in an interview with AJMC. “I know the media really tries to make this story every winter, but even prior to the pandemic, this is respiratory virus season. We are in the thick of it, so the trends that we're seeing in RSV, flu, COVID-19, and norovirus are not alarming to infectious disease specialists because these are the normal viruses that circulate around this time of year.”²

Although these terms can make seasonal virus surges sound alarming, it is critical to remember that respiratory illnesses historically circulate more frequently in the winter months. What has changed is public awareness and access to testing, which allows for more precise tracking and reporting than in the past. Increased visibility of case numbers can create a sense of heightened concern, but it also helps individuals and health officials make informed decisions about prevention and care.²

One virus seeing a significant surge this season is norovirus, a common, highly contagious gastrointestinal infection that causes painful stomach cramps, nausea, vomiting, and diarrhea. Cases have spiked across the country, leading to hospitalizations and even school closures. In Polk County, Georgia, the district closed all schools on January 31, 2025, and moved to virtual learning due to 800 student and 61 administrative cases of norovirus, as well as widespread cases of influenza. In New Jersey, state health officials reported a 350% increase in cases compared with 2023.^3,4

“This year, the number of reported norovirus outbreaks has exceeded the numbers that we’ve seen recently and in the years before the pandemic,” a CDC spokesperson told NJ.com.³

Rates of RSV are declining whereas influenza rates are up. For the week ending on January 25, 2025, 44 states had high or very high virus activity, including New Jersey, New York, New Hampshire, Louisiana, South Carolina, and Tennessee. According to the CDC, there were 16 more pediatric flu deaths, pushing the total to 47. The overall level of flu-related mortalities remains steady at 1.6%, but hospitalizations are increasing in all age groups, making up 7% of all emergency department visits.^5,6

COVID-19 cases have risen post-holidays, with wastewater levels now high, especially in the Midwest. The CDC reports growing activity in the Southeast, West, and parts of the Northeast, though test positivity is holding at 5.4%. Emergency visits remain low but are highest in young children and older adults, while hospitalizations and deaths, though declining, remain most common in seniors. Despite this, booster uptake is low, with only 21% of adults and 10% of children vaccinated.^5,7

Alongside the normally circulating seasonal viruses, other outbreaks have also gained significant attention. In Kansas City, Kansas, officials reported an outbreak of TB, with a reported 2 deaths. Of the cases, 67 patients had confirmed active TB infections and 79 had confirmed latent diagnoses. The source of the outbreak is unknown, but public health officials are working with the CDC to support increased testing and screening efforts.⁸

The H5N1 avian influenza continues to be a significant public health concern across the United States, with 67 confirmed human cases and one death as of January 31, 2025. While human infections remain rare, the virus is spreading among commercial, backyard, and wild birds, prompting the culling of infected flocks. The virus has also been detected in other animal species, such as domestic cats and dairy cattle, raising concerns about its potential to adapt and spread further. Infections have been reported in over 500 species, including 485 avian and at least 70 mammal species.^9,10

Compounding these challenges, the Trump administration has paused the release of key health data, including the CDC's Morbidity and Mortality Weekly Report (MMWR), delaying the dissemination of critical research findings. This lack of timely information could hinder effective public health responses to the ongoing outbreak.¹⁰

As multiple viruses continue to circulate, staying informed and vigilant remains crucial, and pharmacists play a vital role in patient education and prevention strategies. Proper hygiene, including hand washing, is essential to prevent the spread of germs and bacteria. Staying up to date on vaccinations, recognizing early symptoms, and understanding when to seek medical care can help reduce the burden on health care systems.²

“In general, it is respiratory virus season, so get vaccinated, wash your hands, have respiratory etiquette, stay home when you're sick—all of those basic public health prevention measures I think are really important, whether you're talking about avian influenza or seasonal influenza or RSV or COVID-19 or norovirus,” said Shah. “All of those things are still relevant.”²

As respiratory viruses and emerging infections continue to circulate, public awareness and preventive measures remain key to protecting vulnerable populations and minimizing the impact of seasonal outbreaks.

REFERENCES

1. ‘Quad-demic’ hitting US with flu, COVID-19, RSV, norovirus surging. Forbes. January 26, 2025. Accessed February 3, 2025. https://www.forbes.com/sites/brucelee/2025/01/26/quad-demic-hitting-us-with-flu-covid-19-rsv-norovirus-surging/

2. Avian influenza: prevention, progress, and public health priorities. AJMC. January 24, 2025. Accessed February 3, 2025. https://www.ajmc.com/view/avian-influenza-prevention-progress-and-public-health-priorities

3. This nasty stomach bug is spreading in N.J., health officials warn. NJ.com. January 4, 2025. Accessed February 3, 2025. https://www.nj.com/healthfit/2025/01/this-nasty-stomach-bug-is-spreading-in-nj-health-officials-warn.html

4. Georgia school district closes all schools due to flu, norovirus outbreak. WYFF4. January 31, 2025. Accessed February 3, 2025. https://www.wyff4.com/article/georgia-school-district-closes-all-schools-flu-norovirus/63633875

5. US flu activity climbs, with more deaths in kids. CIDRAP. January 31, 2025. Accessed February 3, 2025. https://www.cidrap.umn.edu/covid-19/us-flu-activity-climbs-more-deaths-kids

6. Weekly US influenza surveillance report: key updates for week 4, ending January 25, 2025. CDC. January 31, 2025. Accessed February 3, 2025. https://www.cdc.gov/fluview/surveillance/2025-week-04.html

7. Covid surges across US after holidays amid low booster uptake. The Guardian. January 3, 2025. Accessed February 3, 2025. https://www.theguardian.com/us-news/2025/jan/03/covid-surges-us-low-booster-uptake?utm_source=chatgpt.com 

8. Two dead, dozens sickened in Kansas tuberculosis outbreak. CNN. January 28, 2025. Accessed February 3, 2025. https://www.cnn.com/2025/01/28/health/tuberculosis-outbreak-kansas/index.html

9. H5 bird flu: current situation. CDC. January 31, 2025. Accessed February 3, 2025. https://www.cdc.gov/bird-flu/situation-summary/index.html

10. Bird flu crisis enters new phase. Axios. February 3, 2025. Accessed February 3, 2025. https://www.axios.com/2025/02/03/bird-flu-crisis-new-phase