The Centers for Disease Control and Prevention has issued a health advisory warning U.S. residents about the reemergence of the so-called “swine flu” virus that wreaked havoc in Ohio during a worldwide pandemic in 2009 and 2010.
H1N1 — a subtype of Influenza A flu viruses — has been the “predominant circulating virus” so far this year, according to the Christmas Eve advisory, which noted that the CDC has received numerous reports of people suffering from severe respiratory illness and requiring intensive care treatment after being diagnosed with H1N1.
H1N1 — which can lead to deadly secondary complications, such as pneumonia — was responsible for more than 200,000 deaths worldwide during the 2009-2010 flu season, including at least 52 in Ohio, according to CDC and World Health Organization estimates. The numbers may have been even higher because states are not required to report flu-related deaths of people older than 18 and many of flu-related deaths of young adults may have gone unconfirmed.
The flu virus, which originated in pigs and can be passed directly from swine to people or from person to person, is particularly alarming for health officials because it tends to hit younger, healthier adults harder than older adults and children, like most other flu viruses.
Still, CDC officials were quick to point out that drug companies have developed effective vaccines to fight the virus that were not available during most of the duration of the pandemic, and doctors are generally quicker to diagnose and treat H1N1 as a result of what they have learned from past experience.
H1N1 “was a big concern in 2009 because it was the first time we had seen it in people,” said Dr. Mike Jhung, an epidemiologist in the CDC’s flu division. “Now it’s considered a common seasonal flu virus that we see every year, and we have a flu vaccine that protects against it.”
Despite concerns about H1N1, most areas the United States — including Ohio — have experienced low levels of overall flu activity so far this year, the CDC reports.
“We’re getting off to a mild start,” said Shannon Libby, a spokeswoman for the Ohio Department of Health. “Most of the activity we’ve seen is in northeast Ohio, but it’s still at the local level.”
State health departments report the geographic spread of flu activity on a progressive scale from no activity to sporadic, local, regional, then widespread activity. But in the handful of states — including Louisiana, Mississippi, Alabama and Texas where flu activity is already widespread — nearly a dozen deaths related to the H1N1 virus have been reported.
Local health officials advise anyone 6 months or older who has not been vaccinated yet to get a flu vaccine soon, because flu activity is expected to accelerate during the season’s peak months in January and February.
Charles Patterson, health commissioner for the Clark County Combined Health District, said even if flu activity remains low local residents are still vulnerable to H1N1, especially during the holiday season.
“With all the travel that happens, and people coming in from different regions… this is a time of year when we see some mixing of diseases within regions,” Patterson said, adding that the the health department was actively tracking the spread of H1N1 even though only a handful of flu-related hospitalizations have been reported at Springfield Regional Medical Center —Clark County’s largest hospital.
In Montgomery County, Christmas travel may have contributed to a sharp uptick in confirmed cases of Influenza A, according to John Steele, a spokesman for Public Health - Dayton & Montgomery County.
The number of confirmed cases of Influenza A rose from nine in the week ending Dec. 14 to 65 last week, Steele said, but further testing will be needed to determine whether surge in flu cases was the result of H1N1 specifically or some other subtype of Influenza A.
Most of the confirmed cases were in children or young adults, “which could be an indication” of H1N1 because young adults are the group disproportionately affected by the virus, he added.
Still, the CDC’s Jhung warned against jumping to conclusions, noting it is still too early in the season to predict which influenza viruses will predominate.
“So far, this year is an H1N1 year, but that might change,” he said.