Health officials are warning of a potential “viral convergence” this winter as cases of four major respiratory and gastrointestinal infections — COVID-19, influenza, respiratory syncytial virus (RSV), and norovirus — are expected to rise simultaneously, the Daily Mail reports.
This convergence could place additional strain on the healthcare system, especially with lower-than-usual vaccination rates for flu and COVID-19 this year.
The Four Viruses to Watch
- COVID-19: While COVID-19 cases are currently at low levels, experts predict they will rise during the holiday season and into January. Current testing data shows an uptick in positive COVID-19 test results, with positivity rates increasing from 3.9% in early November to 5.4% by early December.
- Influenza (Flu): Flu cases are on the rise, with hospitalizations for flu-like illnesses up 14% in early December compared to two weeks prior. Louisiana and Georgia are currently experiencing high levels of flu activity, while eight other states, including California, Arizona, and Texas, are recording moderate levels. Flu typically peaks between January and March, and experts expect it to follow a similar pattern this season.
- Respiratory Syncytial Virus (RSV): RSV infections are also increasing. Data shows a hospitalization rate of 1.2 per 100,000 people as of November 30, more than double the rate from earlier that month. RSV is a common cause of respiratory illness in children and older adults, with symptoms often resembling those of the flu or COVID-19.
- Norovirus: This stomach bug, often referred to as the “stomach flu,” is spread through contaminated surfaces and person-to-person contact. Reports indicate that norovirus outbreaks are on the rise, with 40 outbreaks reported in the last week of October, higher than levels seen in any year since 2012.
Experts attribute the expected surge in infections to a combination of seasonal factors. As temperatures drop, people spend more time indoors, increasing close contact with others. Holiday travel and gatherings are also a significant contributor, as more people share enclosed spaces on planes, buses, and trains.
“We are in store for increases in circulation in these four [viruses] over the next couple of months, and that would cause what we call epidemics,” said Dr. Joe Bresee, an infectious disease specialist with two decades of experience at the Centers for Disease Control and Prevention (CDC), explained.
He added that every year, respiratory viruses surge after the holiday season as people return home and back to school or work after travel.
One of the biggest concerns this year is the lower vaccination uptake for both flu and COVID-19. Current CDC data shows that only 38.6% of US adults have received a flu shot this year, which is below last year’s vaccination rate of nearly 40% at the same point. COVID-19 booster uptake is also lagging, with only 17.9% of adults having received the updated shot as of early November, down from 22.6% the previous year.
Dr. Bresee and Dr. Bill Schaffner, an infectious disease expert in Tennessee, are urging people to get vaccinated. Adults over 75 are particularly encouraged to get the RSV vaccine, which has shown to be up to 98% effective at preventing severe illness. However, only 43.1% of older adults have received the one-time shot so far.
While mask mandates have largely been lifted, some health authorities in New York City and Sonoma County, California, have advised residents to resume wearing face masks in certain public settings. Dr. Schaffner has suggested that older adults and people with compromised immune systems consider wearing masks as an “extra layer of protection.”
The effectiveness of face masks has been a topic of debate. A review by the Cochrane Institute found limited evidence that masks prevent respiratory diseases, but health officials still see them as a useful barrier against airborne transmission, particularly in crowded settings.
The anticipated “viral convergence” could put pressure on hospitals, especially if large numbers of people are hospitalized for flu, COVID-19, or RSV at the same time. Hospitalizations for flu-like illness have already increased, with 3.3% of patients admitted for flu-like symptoms in early December, up from 2.9% two weeks earlier. RSV and norovirus hospitalizations are also climbing.
While Dr. Barry Hahn, an emergency medicine physician at Staten Island University Hospital, noted that infection levels have not surged as significantly as in past years, he acknowledged a noticeable rise in RSV cases. If these viruses continue to spread at the predicted rate, hospitals could see higher demand for medical care and intensive care unit (ICU) capacity.
Experts recommend several steps to reduce the risk of infection:
- Vaccination: Get vaccinated for flu, COVID-19, and RSV if eligible.
- Masking: Consider wearing masks in crowded, indoor settings, especially during travel or holiday gatherings.
- Hygiene: Wash hands frequently and disinfect surfaces, as norovirus spreads through contact with contaminated surfaces.
- Travel Precautions: Be aware that planes, buses, and other shared transport systems increase the risk of exposure to airborne and surface-borne viruses.
