(CNN) – So far this season, 105 children have died from influenza, according to data published Friday by the Centers for Disease Control and Prevention (CDC) in the United States. This is the highest number of childhood deaths from influenza at this time of the season since the CDC began keeping records in 2004, with the exception of the 2009 flu pandemic.
It has been an “unusual” flu season with a higher proportion of children and young adults affected than the older population, according to Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University Medical Center.
The previous prevalence of influenza B, a strain of influenza that tends to be more common in children, could be one reason why more children were affected, Schaffner said. In addition, as the number of cases of influenza B decreased, the number of cases of H1N1 increased, he said. H1N1 is a subtype of influenza A strain, which also affects children more than adults.
“This is the first time in 25 years that [la influenza B] it became so common so early, ”said Dr. Buddy Creech, an associate professor of pediatric infectious diseases at the Vanderbilt University Medical Center.
Neither Schaffner nor Creech know why this year’s influenza schedule is so different.
“It’s leaving all flu virologists baffled,” Schaffner said.
That peak of previous influenza B may be one of the reasons why there are more deaths related to pediatric influenza than usual, according to Schaffner.
In addition, influenza B can present with unexpected symptoms, so parents may not seek immediate attention, according to Creech.
“Often, influenza B is more likely to cause gastrointestinal symptoms than influenza A, although both can occur in young children,” he said. “Some parents do not recognize these symptoms as part of the flu … which can delay the thinking of influenza and delay treatment.”
Gastrointestinal symptoms, such as vomiting, can also affect the ability to take antivirals that can shorten the duration of the flu, he said.
Another reason for the higher number of flu-related deaths in children may not be specific for children at all.
“It could simply be a reflection of a particularly severe season,” said Dr. Arnold Monto, a professor of epidemiology at the University of Michigan School of Public Health. Monto said there are many flu-related deaths among children every year in the United States.
Amount agreed that it is a strange season that can last longer.
“It is possible that we have influenza entering in April of this year because it is still strengthening at this time,” he said.
Given the uncertainty about how long this flu season will last, Monto recommended getting a flu shot, explaining that children who die from the flu are more likely to be those who were not vaccinated.
The CDC said this week that they believe the current influenza vaccine is a “substantial protection” for children 6 months to 17 years.
Schaffner also said everyone should get vaccinated, especially because the flu can affect a perfectly healthy person and cause serious illness. At least half of the children dying of the flu were healthy, he said.
“[La vacuna] It may not completely prevent the disease, “Schaffner said,” but if you are vaccinated and still have the flu, you are more likely to have a less serious infection … Your risk of dying is less. “
– Scottie Andrew, John Bonifield and Jen Christensen of CNN contributed to this report.