Enlarge / The influenza virus from an image produced from an image taken with transmission electron microscopy. Viral diameter ranges from around 80 to 120 nm. (credit: Getty | BSIP)

Key indicators of seasonal flu activity declined in the first week of the year, signaling a possible reprieve from the high levels of respiratory virus transmission this season—but the dip may only be temporary.

On Friday, the Centers for Disease Control and Prevention released its latest flu data for the week ending on January 6. Outpatient visits for influenza-like illnesses (ILI) were down that week, the first decline after weeks of rapid increases. Flu test positivity and hospitalizations were also down slightly.

Percent of outpatient visits for respiratory illnesses by week. (credit: CDC)

But transmission is still elevated around the country. Fourteen states have ILI activity at the “very high” level in the current data, down from 22 the week before. And 23 states have “high” activity level, up from 19 the week before. (You can see the week-by-week progression of this year’s flu season in the US here.)