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This flu season is on track to be the worst in nearly a decade

Here's a look at how the flu virus infects the body and produces symptoms. (Video: Joyce Koh/The Washington Post)

With tens of thousands of patients flocking to hospitals and at least 37 children dead, this year’s flu season is shaping up to be the worst in nearly a decade — and it’s not over yet.

At a time when experts hoped new cases would start tapering off, federal health officials said Friday that the number of patients seeking care for flulike symptoms continues to rise sharply.

Nearly 12,000 people have been hospitalized with confirmed cases of flu, an increase of 3,000 in just one week, according to the Centers for Disease Control and Prevention. The latest report, for the week ending Jan. 20, shows the rate of people seeking care now rivals that of the swine-flu pandemic of 2009.

In Florida, West Boca Medical Center in Boca Raton has seen a surge of patients. “We think it may be peaking,” said Adam Leisy, head of the emergency room, “but who knows what the next few weeks will bring.”

Leisy said his hospital has been flooded with elderly snowbirds — often already dealing with chronic conditions and now wheezing from coughs and struggling with fever.

In California, some hospitals have pitched tents outside their emergency rooms to cope with the crush of patients; some facilities there have flown in nurses from out of state. Doctors have worked double and triple shifts. In Chicago, a shortage of patient beds has left ambulances idling outside hospitals.
In New York, state leaders this week issued an emergency order allowing pharmacists to give vaccines to children.

The toll on children has been especially severe. CDC officials said the pediatric death count is likely to approach, if not exceed, the 148 deaths reported during the especially severe flu season of 2014 and 2015. That season ended with 56,000 flu-related deaths, 710,000 people hospitalized and 16 million who sought care from a clinician or hospital.

This year’s intensity has been driven by a particularly nasty strain of the virus known as H3N2. Another strain has also begun showing up, hitting baby boomers especially hard, CDC officials said Friday, although experts have not figured out exactly why.

CDC says the number of pediatric deaths is probably more than the 37 reported, because if often takes longer for deaths outside hospitals to be reported to authorities. The real number may be twice as high, officials said.

The flu can kill tens of millions of people. In 1918, that's exactly what it did.

“You hear people talking about how serious it can get, but you never think it’s going to happen to you,” Anne LaMontagne, 41, said by phone as she sat by her son in Children's Minnesota in Minneapolis.

In the space of five days, 9-year-old Grant went from having a sore throat to being rushed to the hospital, with doctors struggling to force more oxygen into his lungs to keep him alive.

The flu led to pneumonia. Her son’s lungs filled with mucus, preventing him from breathing. Doctors put the boy on a ventilator and stuck a probe down his throat to suction out vinelike threads of mucus from his lungs.

But his condition got worse. Last week, LaMontagne and her husband looked on with horror as doctors inserted a large tube into an unconscious Grant’s neck and connected him to a lung-bypass machine to give his body the oxygen his lungs could not.

The sight sent the couple fleeing to the hospital cafeteria. “We just cried and tried to breathe and talk each other through what was happening,” she said.

The treatment worked. Last Friday her son had recovered to the point that doctors woke him from sedation. “It all happened so fast,” his mother said Friday. “He’s a healthy boy. He swims. He’s never had any major illnesses.”

Two differences with this year’s flu season is that it hit almost all states at the same time and has stayed at that high level nationally for three consecutive weeks, said Daniel Jernigan, who heads the CDC’s influenza division. In past years, the flu more commonly appeared in different parts of the country at different times.

Flu season began in October, but there was a rapid ramp-up in January right after the holidays, probably triggered by children returning to school and spreading the virus, Jernigan said. In Florida and Texas, entire school districts have closed to curb further spread.

The burden of so many cases on hospitals, experts say, underscores the fragility of the country’s health-care system. Some hospitals are already strained to capacity on a normal day and could be overrun if a pandemic hits.

“The concern is that with an emergency, we could get to a tipping point, where the demands of community exceeds our capacity as a country,” said James Blumenstock, chief program officer for the Association of State and Territorial Health Officials.

The length and severity of a flu season is notoriously hard to predict. Experts often look for clues in past seasons when the same strains of flu have dominated. In previous H3N2 seasons, flu activity remained active for an average of about 16 weeks but in some cases continued as long as 20 weeks.
“By that measure, we are about halfway there,” Jernigan said. “But it means we have several more weeks of flu to go.”

More people are seeking care for flulike illness than at any time since the 2009-2010 swine flu pandemic that swept the country. Aside from that pandemic season, the last time the country experienced such high levels of influenza-like illness was in 2003-2004.

Already, this season has offered its share of surprises.

People over 65 are usually the ones with the highest hospitalization rates, with the second-most-affected group being children under 4. But officials have been taken aback in recent weeks to see that individuals with the second-highest hospitalization rate are between 50 to 64 years old. This season, the hospitalization rate for those 50 to 64 is 44.2 per 100,000 people, which is significantly higher than rates for the past several flu seasons.

“Baby boomers have higher rates of hospitalization than their grandchildren right now,” Jernigan noted with surprise.

It’s not clear why this is happening. Officials say one possibility may be the mix of viruses circulating this season and the different levels of immunity that people have developed to those viruses over time.

Besides H3N2, the two other flu strains causing illness are H1N1, an influenza  strain that caused the 2009-2010 swine flu pandemic but is now a regular human flu virus, and an influenza B strain.

H1N1 viruses don't tend to be as bad for the elderly those over 65 because those individuals were most likely exposed as children and have built up immunity; for the same reason, those viruses tend to be worse for non-elderly adults.

In addition, vaccination rates for adults under 65 are lower than those for seniors.

“These are folks who would really benefit from higher vaccination rates,” Jernigan said. “They’re usually at the peak of their careers, or managing a lot of business, and them missing work because of flu would have a huge impact.”

This year’s seasonal flu epidemic is especially severe, according to the Centers for Disease Control, which says the deadly virus is now in every U.S. state. (Video: Reuters)

It is not too late to get a flu shot, experts continue to stress. The current vaccine protects against all three of the most prevalent strains. It is least effective against the H3N2 strain, but its effectiveness against the other two strains that are now appearing — H1N1 and an influenza B strain — is much higher.

The CDC recommends an injectable flu vaccine for everyone 6 months or older as soon as possible because the body takes about two weeks to produce a full immune response.

The one upside to the severity of this year’s season is that suddenly everyone wants to know how to avoid getting sick.

“I have friends calling me, family asking me, ‘Is it too late to get a shot?’ ” said Blumenstock, a health official in Arlington, Va. “I tell them: ‘Hurry up. Go! Get your shot.’ Hopefully, this year is a chance for people to learn.”

Julie Tate contributed to this report.

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