It's not time to breathe easy yet, officials with the U.S. Centers for Disease Control and Prevention warn -- but the fact remains that flu-like illness accounted for fewer doctor visits this week than it did last week.
This past week represented the third consecutive week of national decreases in flu reports after four consecutive weeks of sharp increases. As health officials note that nearly all of the influenza that is currently circulating is the novel H1N1 swine flu strain, the downturn has offered hope for some that the country may have turned the corner on this wave of the pandemic illness.
"We might actually be beyond the peak," Dr. Pascal James Imperato, dean of the School of Public Health at SUNY Downstate in New York, told ABC News' David Muir. Imperato, who has studied influenza for 37 years, said the decline in flu activity may indicate "the beginning of a downswing."
Still, Dr. Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases, said Friday that even though reports of the flu may be at a nationwide lull for now, it does not necessarily mean we're out of the woods yet.
"The national average looking lower doesn't mean that in every state or community that it's a little better this week than before," Schuchat said during a press conference. "I wish I knew if we had hit the peak ... even when a peak has occurred, half of the people who are going to get ill haven't gotten ill yet. A peak in outpatient activity is not the same as a peak in hospitalizations and deaths, which often lag."
Forty-three states still have geographically widespread flu activity; 21 flu pediatric deaths were reported this week, 15 of which were confirmed to be due to H1N1. According to the CDC, influenza levels are still well above what is expected for this time of year, and they could surge again.
Meanwhile, health officials and health care providers in many areas of the country are breathing a sigh of relief -- albeit a cautious one -- as the number of confirmed cases of H1N1, as well as flu-related emergency room visits and ICU cases, begins to decline.
In addition to reports from health departments across the country of a decrease in flu activity, ABC News heard from 30 hospitals throughout the country that say flu activity is down.
"The wave has crested in our region. The real question now is how long the wave will continue to roll ashore," said Frank James, health officer for San Juan County, Wash. "We could still be seeing cases into the winter months."
In Maryland, health officials have reported declining levels of hospitalization for swine flu since a spike last month.
"In the last several weeks we are noticing a downturn [and] it appears we have reached a peak in this outbreak," Maryland's secretary of the Department of Health and Mental Hygiene, John Colmers told ABC News.
Two months ago, Dell's Children's Medical Center in Austin, Tex. had to set up tents outside the hospital to handle the influx of as many as 280 flu patients a day, doctors at the hospital told Muir. But as of Thursday, most of these tents are down, as are the numbers of flu cases; the hospital is seeing about 70 flu patients a day now -- one quarter of what they were seeing before.
State data for Pennsylvania also indicate that the fall wave of H1N1 appears to have peaked in late October, says state health department spokeswoman Stacy Kriedeman. Though current activity far exceeds levels seen during normal influenza seasons, the department reports that since the beginning of November, there have been "clear declines in overall reporting from all areas of the state."
In Colorado, state officials also reported in a recent press release that surveillance data indicates that flu levels "peaked" in early October for the Denver metropolitan area. At Denver Health medical center, a hospital spokesperson reports that flu activity has seen a steady decline over the last few weeks and is now at the level one would expect for a normal flu season.
Additionally, health officials in Wyoming, Minnesota, and Nebraska, have all publically noted a decline in flu activity for their regions, according to the AP, and state data released by North Carolina and Rhode Island show a decline in overall flu activity.
The number of flu patients at Rhode Island Hospital and Hasbro Children's Hospital in Providence peaked at the beginning of November and is now dropping off, according to a spokesperson there.
In Kentucky's Barren River district, the district director, Dennis Chaney, said they are seeing a "gradual decline" in confirmed H1N1 cases, including numbers of ICU patients hospitalized with flu complications.
Chaney said, "I really feel that, in general, the community is taking personal responsibility for their behaviors as it relates to staying home if they're sick. Those campaigns for personal responsibility are being effective."
In Hillsborough County, Fla., however, a decline in emergency room visits doesn't necessarily indicate an overall decline in flu cases, according to health department spokesman Steve Huard. The increase in over-the-counter medicine sales tracked by the state suggests that many who come down with a less severe case of flu are "getting the message," Huard said, and treating themselves from home.
Widespread levels of flu in the state are still "chugging along," he said, but there may not be as many people going to the ER.
"We do believe our messages have been heeded by the public," said Kriedeman. " [The Pennsylvania Department of Health] has repeatedly emphasized…that most persons with the flu who…do not have danger signs of illness can generally remain at home and not seek health care."
Antiviral prescriptions, over the counter medicine use, and reports from "sentinel" health providers such as physicians, university medical centers and local health departments, are all additional measures that some states use to gauge the levels of flu activity among those who are not sick enough to merit a trip to the emergency room, or even a visit to their physician.
"Our most effective tracking tool [for San Juan County, Wash.] was real time school reporting of absent students…because most people do not seek medical evaluation with flu symptoms, this is an earlier indication of influenza than physician reporting, and much earlier that ER visits or ICU care," says James.
In Pennsylvania, statewide surveillance includes, among other things, absenteeism for 300 sentinel schools and reports from 150 sentinel health care providers. These systems provide a sense of less-severe flu cases in the state and are showing similar declines to those seen in ER visits and flu hospitalizations, Kriedeman says.
But even with a real decline or leveling out of flu activity, the battle's not over, said Doc Kokol, director of communications for the Florida Department of Health. The state tracks visits to the emergency room and gauges physicians' visits from reports of 100 sentinel physicians throughout the state, and in a press release Tuesday, state officials reported 1,082 lab-confirmed cases of H1N1, and 167 deaths.
"We are beginning to see somewhat of a plateau, but that doesn't mean that flu has leveled off….H1N1 flu, like other [kinds of] flu, goes in waves; this [report] is really only a snapshot in time."
In Maryland, Colmers voices a similar caution: "Why [it's declining], or whether it will be sustained, we don't know…[so] we are all saying that we are not out of the woods yet."