'Tripledemic' Waning In PA Despite Early Boom: Here's Why

PENNSYLVANIA — Following two straight winters of exploding case rates and overcrowded hospital rooms that sickened and killed thousands in Pennsylvania and around the nation, the threat of viruses seems to be waning in 2023.

That's despite early warnings of a "tripledemic," the confluence of COVID-19, seasonal flu, and respiratory syncytial virus, or RSV, potentially crippling healthcare systems across the nation.

These warnings were largely in place due to what health officials are now calling an "early peak" of both RSV and the flu. Both illnesses reached historic levels in November and early December in Pennsylvania, but have steadily trailed off since then. Health officials say the reason is "immunity debt" incurred by people who were protected their immune systems from everything, including germs that would build immunity to diseases like flu and RSV, over the past two years.

“Population immunity was very low against these viruses," virus expert Scott Hensley, with the University of Pennsylvania's Perelman School of Medicine, said in a university publication Wednesday. "Once the spark occurred, there was just this huge, immunologically naïve population out there. That’s why RSV and influenza viruses have spread so rapidly."

In early November, Pennsylvania's five week average of RSV cases spiked to as high as 710.7 cases, according to data from the Centers for Disease Control and Prevention. That's higher than it's ever been.

And in early December, Pennsylvania's number of laboratory confirmed flu cases soared to around 1,450 a week, far higher than it typically is that early in the winter. Even though COVID-19 cases had remained low at that point, health experts had every reason to believe a potential superstorm of viruses could overcrowd hospitals and emergency rooms in particular — especially after coronavirus had done it all alone the previous two years.

It was enough for the alarm bell to be run. Pennsylvania's Acting Health Secretary Denise Johnson said the flu season had the potential to be "severe."

And while cases have plummeted since then, they weren't wrong. Increased hospitalizations due to the flu and RSV spikes backed up emergency rooms in Pennsylvania and elsewhere that had been strained since the pandemic began. At Children's Hospital of Philadelphia, beds were near or at capacity for weeks. As of early November, Pennsylvania hospitals were faring worse than the rest of the nation, data from Johns Hopkins University showed. Some 79 percent of beds were taken at that time, including 76 percent of ICU beds.

Illnesses have been more severe this year, too, especially among children.

"We have definitely seen more kids with flu this year, and many of those kids are more sick because of the flu than they have been in the past," Jackie Calhoun, a pediatric critical care nurse practitioner at the UPMC Children’s Hospital of Pittsburgh, told Patch.

Experts say that the massive push towards vaccinations helped limit the damage, and has helped cases of all three infectious diseases plummet even in the midst of the winter.

In Pennsylvania, RSV cases are now at just 71 for a five week average, according to the CDC, down from that November peak of over 700. Flu cases are at about 300 a week, the Pennsylvania Department of Health said, down from over 1400 in December, declaring last week that "seasonal influenza activity in Pennsylvania and the United States is moderate."

COVID-19, meanwhile, never materialized with a fall or winter surge this year in Pennsylvania like it has for two consecutive years. The seven day average of cases is 1,563, according to the latest statistics, about as low as case rates have been over any point of the past nine months.

However, experts warn that we're not out of the woods yet. Winter and flu season aren't yet over, and there is the potential for a second peak of influenza. This is because there are two common types of the flu, influenza A and influenza B, and B is what often strikes in the spring, Penn scientists said.