The flu season has been particularly rough in New York City this year, with four pediatric influenza deaths reported in the city, all in January, according to New York State Health Department.
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The flu has been spreading across the country, with the U.S. Centers for Disease Control and Prevention seeing epidemic levels of flu activity late last month.
There have been 15 flu-related pediatric deaths in the nation this flu season, the CDC reported last week.
New York, New Jersey and Pennsylvania all reported high levels of flu-like activity, according to a CDC flu report last week.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, said that while the deaths are tragic, the number of New York cases is not unusual for the flu season. The New York State Department of Health did not disclose the ages of the children or whether they had been vaccinated or had underlying conditions that put them at additional risk for complications.
"Every year in [Vanderbilt's] pediatric emergency room come children who are otherwise clearly healthy, and they are seriously ill with the flu," Schaffner said. "The lesson is that flu can strike even healthy children."
During the previous flu season, 89 pediatric deaths related to the flu virus were reported in the U.S., according to the CDC.
Public health experts have been concerned about vaccination rates, since pediatricians may have difficulty getting some children vaccinated against the flu if they have an aversion to needles, Schaffner noted. While in the past doctors could vaccinate needle-averse children with a flu mist vaccine, they were advised not to use the flu nasal spray this year because it was found less effective than a vaccine injection.
"It's clear that the substantial majority of children who die from influenza every year have not been vaccinated," Schaffner said, emphasizing that he was speaking generally and not about the recent deaths in New York.
Flu symptoms include headache, fever, joint pain and cough. The seasonal flu generally spreads across the U.S. from November till March, with the peak number of cases often occurring in February.
The number of people affected every year can vary widely, but generally, the CDC reports that "millions of people are sickened, hundreds of thousands are hospitalized and thousands or tens of thousands of people die from flu every year." Children under the age of 1 are at increased likelihood of developing complications if they contract the flu.