• Respiratory illnesses, including influenza, COVID-19, and RSV, are on the rise in the United States, according to CDC reports.
• Norovirus, commonly associated with cruise ship outbreaks, has also been linked to a significant number of cases in recent weeks.
• Older adults and young children are identified as the most vulnerable groups for severe respiratory illnesses that may result in hospitalization.

Understanding the Current Surge in Illnesses

This flu season is shaping up to be more than just a typical cold season, as a mix of respiratory viruses—including influenza, COVID-19, and respiratory syncytial virus (RSV)—is spreading rapidly across the United States. This scenario, compounded by a surge of the highly contagious norovirus, may give the impression that nearly everyone is falling ill.

Data from the CDC shows a marked increase in influenza cases since December, indicating a significant upward trend nationwide. Other respiratory viruses, such as COVID-19 and RSV, are also experiencing high levels of activity, with expectations for further increases as winter continues.

“Influenza is certainly on the rise. We’ve seen an upward trend over the past month,” stated Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, in an interview with Healthline.

Norovirus, often referred to as “winter vomiting disease,” is responsible for a notable number of outbreaks. In the first week of December alone, health departments across various states reported 91 outbreaks of norovirus, significantly higher than the average in previous years.

Despite this wave of viral activity, experts suggest that this year’s situation aligns closely with what has been observed in previous years, excluding the anomalies caused by the COVID-19 pandemic.

“The current season isn’t dramatically worse than in years past,” commented Dr. Dean Winslow, an infectious disease expert at Stanford Medicine. “It’s a return to what we typically see.”

The Impact of COVID-19 on Seasonal Illness Patterns

Flu season has always been a predictable part of the annual cycle, but the COVID-19 pandemic that began in 2020 altered this pattern. Since then, COVID-19 has remained an underlying presence, surfacing intermittently alongside flu but not necessarily following the same seasonal timeline.

“Now, COVID-19 is integrated into our viral environment, much like other seasonal viruses,” noted Schaffner.

However, it’s important to recognize that COVID-19 tends to peak twice a year—once in the summer and again in the winter, while flu, RSV, and other common cold viruses typically see increased activity during the winter months.

While emergency department visits for COVID-19 remain relatively low compared to flu and RSV cases this year, they are gradually rising, as reported by the CDC.

Dr. Judith O’Donnell, section chief of Infectious Diseases at Penn Presbyterian Medical Center, described the trends observed in respiratory viruses as “very typical.” Currently, RSV is a leading cause of respiratory-related hospitalizations, affecting an estimated 80,000 children under five each year.

“Our primary concern lies with RSV in infants under six months, as they can become severely ill and develop bronchiolitis, which is an infection and inflammation of the small airways,” warned Winslow.

Norovirus: A New Challenge This Winter

This winter, a novel strain of norovirus, GII.17[P17], has emerged, leading to multiple outbreaks. This highly transmissible virus is known for causing severe gastrointestinal symptoms, including intense diarrhea and vomiting.

Dr. O’Donnell noted that this strain of norovirus has become more prevalent this winter compared to previous years. Reports indicate that 70% of patients linked to recent outbreaks tested positive for this new strain, as opposed to the previously dominant GII.4 strain.

“Unlike respiratory viruses, norovirus primarily affects the gastrointestinal system, targeting your stomach and intestines. It spreads rapidly between individuals and can persist on surfaces for extended periods,” explained Schaffner.

Norovirus is particularly prone to causing outbreaks in crowded environments such as cruise ships, nursing homes, senior centers, schools, and prisons, where close quarters facilitate its transmission. The cruise industry, in particular, faced a challenging year for norovirus outbreaks, with the CDC confirming six outbreaks in December alone.

Staying Healthy Amidst Rising Cases

As the number of respiratory illnesses rises, it’s important to adopt a comprehensive approach to protect yourself. Vaccination remains the most effective strategy for preventing COVID-19 and flu infections or at least mitigating their severity. While an RSV vaccine is available, it is currently limited to specific populations.

Your healthcare provider may also prescribe antiviral medications if you contract COVID-19 or flu, with Paxlovid recommended for COVID-19 and Tamiflu (oseltamivir) for the flu.

Additionally, practicing good hygiene can help reduce the spread of both respiratory viruses and norovirus. Regular handwashing is essential, and wearing a well-fitting mask can be beneficial if you are in crowded places and concerned about illness. Avoiding large gatherings and staying home when sick are also critical measures.

While sanitizing gels and sprays can help limit the transmission of respiratory viruses, they are generally less effective against norovirus. “Most hand sanitizers are alcohol-based, which are not reliable against norovirus,” Winslow cautioned. “Thorough handwashing is your best defense.”

As respiratory illnesses like influenza, COVID-19, and RSV continue to rise, the current figures are comparable to those of previous years. The emergence of the GII.17[P17] strain of norovirus has compounded the issue, highlighting the importance of vaccination and preventive measures to maintain health during this challenging season.