The flu has begun to spread earlier than usual in some parts of the country, raising concerns that cases could soon surge as millions of Americans travel and gather for Thanksgiving and other upcoming holidays.
The warning signs come as a variant of the virus, called H3N2 subtype K, has caused massive outbreaks in Canada and the UK.
Dr. Cameron Wolfe, an infectious disease specialist at Duke University School of Medicine in Durham, North Carolina, said he has seen a sharp increase in flu cases over the past few weeks.
“Typically, I might see one or two cases a week at this point,” Wolfe said. “Right now, we have two, three, four people coming in per day.”
Alicia Budd, head of the Centers for Disease Control and Prevention’s domestic influenza surveillance team, said: “We certainly expect we will see an increase in influenza activity over the next several weeks.”
According to the CDC, most of the flu spreading in the US so far this season has been the H3N2 strain. H3N2 flu causes more hospitalizations and deaths in older adults.
The initial surge in cases could pose unique risks to this age group, Wolfe said.
“If you’re looking at a really early flu season, you run the risk that some nursing homes may not have completed their vaccine deployment. A hospital may not have fully vaccinated their staff,” Wolfe said. “For example, the community in general may not be as safe as it might have been if a virus emerged in January.”
While flu activity is considered low overall, the CDC’s latest flu report shows cases are increasing. The agency estimates that at least 650,000 people have fallen ill with the flu so far this season. According to reports, about 7,400 people have been hospitalized and 300 have died.
Budd said the increase in cases and emergency room visits is mostly occurring in children.
Last year, 280 children died of flu in America. Excluding the 2009–10 H1N1 pandemic, this was the deadliest flu season ever for children.
No child deaths have been reported so far this season. Still, the early surge in flu activity is troubling for doctors who spent last winter watching the virus spread in schools, day cares and, as a result, hospitals.
“It feels like the calm before the storm,” said Dr. Buddy Creech, a pediatric infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee. “We may have a tough influenza year.”
The H3N2 strain is known for its ability to mutate easily. A subclade K form of the strain emerged in the summer with some mutations. It emerged after the makeup of this season’s flu shots was set.
CDC’s Budd said the agency is studying how well the flu vaccine matches this latest flu strain. Still, he encouraged people to get vaccinated.
Budd said the agency is studying how well the flu vaccine matches this latest flu strain. Still, she encouraged people to get vaccinated.
“Even in years where the strain in the vaccine may not be the same as the strains we are seeing circulating, we know the vaccine can help prevent the severity of disease,” Budd said.
Doctors across the United States are closely monitoring the rise in flu cases.
“Does it turn up our antennae a little bit more? Yes,” said Dr. Daniel Varga, chief physician executive of Hackensack Meridian Health in New Jersey. “This makes us even more cautious given the traditional monitoring done at the local level.”
Dr. Melanie Kitagawa, medical director of the pediatric intensive care unit at Texas Children’s Hospital in Houston, said it’s not too late to get a flu vaccine.
“The more people we can get vaccinated before flu season starts, the better,” Kitagawa said.
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