By Donald Gilpin

As the fall flu season hits earlier and with more than its usual force, it threatens to converge with a new surge in COVID-19 cases and higher-than-ever levels of the respiratory syncytial virus (RSV) in children.

Public health officials have warned of the possibility of a “tripledemic” of flu, COVID-19, and RSV, with colder weather approaching, more indoor gatherings on the schedule, and most masking and social distancing restrictions relaxed.

In a November 1 email, Princeton Deputy Administrator for Health and Human Services Jeff Grosser reported that local emergency department visits associated with influenza-like illnesses are higher this week than last week and higher than they were this week last year, that RSV cases have been increasing rapidly through the month of October, and that reported COVID-19 case numbers have been moving upwards — New Jersey cases up 15 percent in the past two weeks —though Mercer County and Princeton have recently remained on the “low” level of CDC COVID-19 community transmission.

Grosser discussed possible causes for the increased threats from the three most prominent viruses currently circulating.  He cited “the de-escalation in pandemic-related community precautions,” like mask wearing and physical distancing, as “likely a huge driver in why we are seeing this increase in respiratory illnesses.”

Grosser also noted the vulnerable immune systems of many babies, who are most susceptible to RSV. “A highly vulnerable population of babies and children may have been sheltered during pandemic lockdowns, which has led to immune systems that might not be as prepared to fight various respiratory viruses,” he said.

Before COVID-19, in worse influenza and RSV years, the country would see more than 35,000 hospitalizations and 3,000 deaths per week, Grosser pointed out. “We witnessed a remarkable decline in respiratory illnesses like RSV and flu as the pandemic shut down schools, day cares, and businesses,” he said. “But as public gatherings increased and locations opened, we observed an increase in these cases back in the summer of 2021, even though we typically see these illnesses as fall and winter viruses.”

RSV is a common respiratory virus that usually causes mild, cold-like symptoms, Grosser explained. But it can be serious, especially for infants and older adults. It is the most common cause of bronchiolitis and pneumonia in children younger than 1 in the United States. One or two out of every 100 children younger than 6 months of age with RSV infection may need to be hospitalized. 

Older adults who get very sick from RSV may need to be hospitalized. Because of weakened immune systems older adults are at greater risk for serious complications from RSV.

Grosser offered advice for Princeton residents and others who are eager to combat these three and other infectious diseases. “Much of the population knows how to reduce COVID-19 transmission,” he wrote. “The community has heard from us on how to do this, and many residents, businesses, and schools have gone above and beyond keeping outbreaks and disease transmission from happening. This is a great thing and exactly what we as a health department would hope the community would do, especially since many of these precautions are also effective against other respiratory infections like RSV and flu.”

He continued, “Masking, indoor air ventilation and filtration, physical distancing, and of course staying home from school or work or other gatherings if you’re not feeling well are measures that will help curb community transmission.”