Flu activity peaks without post-holiday spike in cases, but respiratory virus season still in full swing

CNN
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Influenza continues to be highly prevalent in the United States, but the first wave of the season, which swept the country weeks earlier than usual, appears to have peaked.

High levels of infections and hospitalizations continued in the weeks following the New Year holidays, but flu activity does not appear to have surged, as many public health experts have warned.

Yet, even after weeks of improvement, data More than 12,400 people were hospitalized with flu in the first week of the new year, and nearly 9% of lab tests were positive for the flu, according to a report released Friday by the US Centers for Disease Control and Prevention.

About 4% of people who visited health care providers last week had symptoms of respiratory virus such as cough and sore throat in addition to fever, almost double the national norm.

Influenza is notoriously unpredictable, with multiple peaks of activity occurring during a single season.

“We’ve clearly had a peak in activity, but that doesn’t mean there won’t be another one,” said Lynette Brammer, leader of the CDC’s National Flu Surveillance Team, last week. “Things can turn around and get back on track.”

Flu vaccination rates are far below ideal levels, hospitals remain overcrowded, and the United States remains vulnerable as the respiratory virus season drags on.

“That’s certainly something we’re really watching closely. We’re keeping an eye on all the data, looking at what virus is spreading, who’s getting sick, what impact it’s having. We’ll have to see,” Brammer said.

“And if you haven’t gotten vaccinated yet, get one. It’s never too late.”

As of December 31, approximately 171 million doses of influenza vaccine have been distributed in the United States, enough to cover about half the population. By the end of November, only 40% of adults had been vaccinated, and by the end of December he had only 48% of children vaccinated, according to the CDC. data.

By January 7, the CDC estimated that there had been 24 million illnesses, 260,000 hospitalizations and 16,000 flu deaths this season.

This season has hit earlier than usual, but at least so far, the results are within the expected range.

“It’s not an unusually high flu season. It seems to be in the moderate to high range, but unfortunately within the range you’d expect to see in a normal flu season,” Brammer said. So basically, except for the timing, this looks like a typical flu season, just a little earlier than usual.”

Overall, influenza and other respiratory virus activity remains “high” or “very high” in about half the states, according to new CDC data, and the U.S. has multiple cases circulating at high levels. We continue to fight against respiratory viruses.

RSV activity also peaked in the United States, reaching a season high in mid-November.But even after a steep decline in trends over the past month and a half, weekly hospitalization rate RSV values ​​remain higher than the recent seasonal peaks.

RSV is particularly dangerous for children, with at least 13 out of 100,000 children under the age of 5 being hospitalized with RSV in the last week of the year, and the cumulative hospitalization rate this season is 5 out of 1,000 children in this age group. became a person .

Meanwhile, Covid-19 activity has been trending upward over the past few months.

Hospitalizations have been on the rise since November, surpassing the latest peak from this summer before the latest booster shots became available. data indicate.

Wastewater monitoring, although case reporting became more irregular over the course of the pandemic data Data from Biobot Analytics also suggests Covid-19 activity is higher than during the delta spike.

The fast-growing Omicron subvariant XBB.1.5 now accounts for an estimated 43% of new Covid-19 cases in the United States, making it the newest infectious strain in the United States, according to the CDC. .

Notably, this is the only variant that has gained support in the United States.

XBB.1.5 was first detected in New York in October. Spreading rapidly across the Northeast, the CDC estimates he accounts for more than 80% of new cases in the region.

From there, XBB.1.5 seems to be gaining momentum along the Eastern Seaboard. Mid-Atlantic states now account for about half of Covid-19 cases, and the Southeast accounts for about one-third of cases.

The rise of XBB.1.5 coincides with an increase in hospitalizations due to Covid-19, especially among the elderly.

XBB.1.5 has important mutations that help it bind more tightly to cells. Experts believe it may be making it more contagious.

Yet only 16% of the US population has received the latest Covid-19 booster shots. Data from October showed that those aged 5 and older who received the latest booster were 19 times less likely to die from Covid-19 than those who were not vaccinated. Those who had the latest booster had a one in three chance of testing positive.