THURSDAY, Sept. 27, 2018 (HealthDay News) -- Influenza killed an estimated 80,000 Americans during last winter's flu season, making it the deadliest season in more than four decades, U.S. health officials reported Thursday.
A particularly virulent flu strain, H3N2, rampaged across the United States during the 2017-2018 season, causing a record number of deaths and hospitalizations, the data from the U.S. Centers for Disease Control and Prevention shows.
Compounding the problem, flu vaccination rates also dipped last year, leaving more people vulnerable to the virus, added U.S. Surgeon General Dr. Jerome Adams.
"Those two things combined to make it a particularly bad flu season," Adams explained.
At a news briefing Thursday, Adams and other public health officials urged Americans to get their annual flu shot, to protect both themselves and those around them.
Dr. William Schaffner, director of the National Foundation for Infectious Diseases, said, "Getting vaccinated is the socially responsible thing to do. While protecting yourself, you are also protecting those around you."
The estimated 80,000 who died from flu and its complications last winter amounted to the most seasonal deaths since the CDC started calculating flu season death tolls in 1976, CDC spokeswoman Kristen Nordlund told CNN.
The worst recent flu season on record had been 2012-2013, during which 56,000 people died. H3N2 flu predominated that season as well.
A record 180 children died from the flu during the 2017-2018 season, exceeding the 171 deaths that occurred during the 2012-2013 season, the CDC reported.
"A majority of them were unvaccinated," Adams said. During most flu seasons, eight out of 10 reported pediatric deaths occur in children not fully vaccinated against flu.
In addition, a record-breaking 900,000 hospitalizations were caused by the flu during the last season, prompting news coverage of hospitals overflowing with sick people.
The 2017-2018 season is the first ever to be classified as high severity across all age groups, the CDC added.
It didn't help that vaccination rates dipped even as the United States faced this deadly wave of flu, infection experts said.
Overall vaccinations declined by 1.1 percent, to 57.9 percent from 59 percent the previous season.
More troubling were declines in specific groups that either are vulnerable to the flu or in a position to further spread the virus.
Fewer children aged 6 months to 4 years old received a flu shot last season, Adams said.
"These kids are often particularly vulnerable to serious complications if they get sick, even if they were previously healthy," Adams said.
Young children also are prime vectors for spreading the flu throughout their families, including grandparents whose immune systems aren't as capable of battling the virus, explained Dr. Wendy Sue Swanson. She is chief of digital innovation at Seattle Children's Hospital and a mother of two little boys.
"Kids have a lot of snot and they have a lot of drool, and they go to school," Swanson said. "And when they go to school, they share all of those secretions. Now, they're lovely and we love them, but they are a lot of the reason flu moves around communities."
There also was a decline in vaccination rates among pregnant women during the last flu season, the CDC said.
The immune systems of pregnant women are compromised, making them more vulnerable to the flu, explained Dr. Laura Elizabeth Riley, director of obstetrics and gynecology infectious disease at Massachusetts General Hospital in Boston.
"When pregnant women get really high fever for extended periods of time, we know that fever actually causes birth defects," Riley said. "That's something that is preventable."
And Adams added that pregnant women who get a flu shot also help protect their unborn babies. Children younger than 6 months can't receive a flu shot, so their only guard against the flu is whatever antibodies have passed to them from their mothers.
Swanson pointed out that "a child who's born to a mom who's immunized has a 72 percent reduction in having hospitalization from flu in those first months of life."
A number of vaccine types are available, including a nasal spray, public health officials said Thursday.
Adams led by example at Thursday's news briefing, receiving his flu vaccination along with former Cleveland Browns lineman Joe Thomas and Dr. Scott Gottlieb, commissioner of the U.S. Food and Drug Administration.
The U.S. Centers for Disease Control and Prevention has more about the 2017-2018 flu season.