A new analysis, using H1N1 deaths in the United States in the spring and projecting likely outcomes for this fall, shows that a typical -- or possibly even a milder flu season than average -- should have been expected.
The finding begs the question: Has swine flu been oversold?
The new study, done by researchers at Harvard University and the Medical Research Council Biostatistics Unit in the U.K., says swine flu cases in the spring indicated a flu season that might be, at worst, slightly worse than normal.
"It would have been great to have that back in June," said Philip Alcabes, an associate professor in the program in urban public health at Hunter College's School of Health Sciences. "There would have been one more bit of evidence behind my assertion six months ago" that people were overreacting to H1N1.
He added, "I'm not saying they could have done that [analysis] even faster."
Around the time that swine flu first started making headlines, Alcabes' book, "Dread: How Fear and Fantasy Have Fueled Epidemics From the Black Death to Avian Flu," was published, and he said the circumstances surrounding H1N1 provide an apt case study.
"I think that it was, from the very beginning, created as a crisis and overstated as a real threat," he said, adding that he did not want to understate the seriousness of influenza.
"Flu is a serious illness, it kills people," he said. But, he added, "It does a disservice to public health when, in the name of a preparedness crusade, people create a narrative of crisis or catastrophe before we have enough data that this is happening."
Alcabes said that while public officials, in the early going, admitted to having little data on the virus and resisted calls to close the borders. But as time went on, he said, officials took many steps he feels were unnecessary, including mass, rather than targeted vaccination.
While the new paper suggests swine flu was unlikely to create a severe epidemic, the researchers, disagreeing with Alcabes, say they do not think public health officials overreacted.
"In the early on, we would not have been able to estimate severity. We were going with what was known at the time," said Anne Presanis, a statistician with the Medical Research Council Biostatistics Unit.
"I don't think it's been oversold," he said. "I think you have to prepare for the worst and then be gratified that it wasn't as bad as it was."
While H1N1 affected different age groups from a typical flu, the intensity of that difference was not yet known in the spring.
"When it first hit, nobody knew how severe it could be or that population aged 60 and over would be relatively spared," said Schaffner. "Had this virus had an impact in the age 60 or over, it would have been vastly more injurious than seasonal influenza. We were fortunate in that regard, but we didn't know that at the time."
Public health officials faced a tough choice in May and June, said Robert Field, a professor of health management and policy at the Drexel University School of Public Health. Had they done little and an epidemic occurred, they would have been blamed for doing nothing. If they did a lot and there had been no major outbreak -- or even if their efforts stopped a potential outbreak -- they would have been blamed for wasting money.
"The attitude of public health is better to be safe than sorry, and to some extent, we may be seeing a milder epidemic than we feared because of the vaccine and other measures people are taking," Field said. "It's so easy to be a victim of your own success -- no one ever sees the disease that's being prevented, you just see the one that appeared and then got cured. It's a consequence of any disease that you develop a vaccine for and more broadly, of any disease that you're able to prevent."
It is not clear how H1N1 will act in the coming months. While swine flu cases have hit their peak, public health officials are saying they expect another peak of influenza in winter, around the time when flu season typically peaks.
On the East Coast, the winter cold has just settled in, so it is unclear what effect that will have on swine flu numbers.
"I am concerned that as more H1N1 vaccine arrives, people won't be as motivated to spend the time and energy to get it," said Schaffner. "We'll begin to see the vaccine left in the refrigerator while the virus continues to get people sick. H1N1 seems to persist because so many people are susceptible."
Such a phenomenon is typical for flu season, where vaccination peaks before Thanksgiving, but the majority of cases come in January and February.
"We're now beginning to enter the period of time of the regular seasonal influenza viruses," said Schaffner, explaining that he expects a mix of seasonal flu and H1N1, but is not sure of the proportions.
"I'm a little unsure of the relative proportions."
Schaffner does not believe that current responses will hurt the credibility of public health officials in the future.
"I would not think so," he said. "This has been an illness that has been pretty widespread throughout the country. Almost everyone knows someone who has been affected."
But Alcabes said while he does not know how people will respond to the directives of public health officials in the future, he thinks it is a concern.
"This was mild, and that's no relief to the families of people who died from it," he said."One feels terrible for them, but people do die of flu. People die from flu every year."
Because we do not yet know what will happen as flu season continues, Field noted, it is probably too early for Monday-morning quarterbacking.
"The game isn't over yet, it seems to be waning, but we don't know for sure," he said. "You could say it's not over till it's over."