Photo: Centers for Disease Control & Prevention

This season's flu strain has been more virulent and deadly than in recent years. Here's why it's been so dangerous to even healthy adults

This past January, Karlie Illg Slaven, a 37-year-old from Plainfield, Indiana, was killed by the flu. The Indiana University employee had missed her flu shot—she always got a flu shot—due to a scheduling conflict at work, according to WISH-TV. Her final week was spent caring for her sick family, including her two children. Slaven was diagnosed with the flu on a Friday, spent part of the day in the emergency room on Saturday, was back in intensive care unit on Sunday, and died Monday.

This past November, Alani Murrieta, a 20-year-old from Phoenix, Arizona, was killed by the flu. Her entire family got sick after Thanksgiving, all recovering but Murrieta. The mother of two worked six days a week at a warehouse, and “never got sick,” according to her aunt. She was sent home from work after feeling ill on a Sunday, diagnosed with flu and given the antiviral medication TamiFlu at an urgent care clinic on Monday, and died in the hospital on Tuesday from pneumonia caused by the virus, according to BuzzFeed.

This past December, Kyler Baughman, a 21-year-old from Latrobe, Pennsylvania, was killed by the flu. According to WPXI, the exceedingly fit Baughman, who was studying to be a personal trainer, looked sick over Christmas. He left work early the Tuesday after the holiday, and by Wednesday, he was in the ER. After being flown to UPMC Presbyterian in Pittsburgh that same day, he succumbed to sepsis less than 24 hours later.

All of these victims had something in common: They were not supposed to be victims. The flu is dangerous to infants, elderly and the infirm, health officials warn every winter, not to young, healthy people. But this year, cases like the ones above have illustrated just how deadly the flu can be.

The grief of these victims’ loved ones, expressed in quotations and on the evening news, is difficult to comprehend.

But Joan Mann understands perfectly.


Mann’s daughter, Kendra Mann-O’Brien, was 35 and living in the Kansas City area when she got the flu in March 2012. A fashion lover who had worked in merchandising before becoming bedridden while pregnant with her first child, Mann-O’Brien was a full-time mom to two children and a jewelry designer with works for sale in a local boutique. On Friday nights, she and her husband would get together with her parents to catch up over wine.

On April 4, she died. Kendra had no pre-existing health conditions that would seemingly put her at risk.

“When she caught the flu in early March of 2012, she told all of us, ‘I want you guys to stay away,’” Mann said. “We had a spring break trip planned for the following week, so she just didn’t want anyone coming around because she didn’t want us to get it and then we’d have to cancel the trip.”

Heeding her warning, Mann kept in touch with her daughter via text and telephone. Mann-O’Brien went to urgent care and received a flu diagnosis a few days after her sickness began; while her vitals were good, there was a slight wheeze in her breathing, which was not investigated via x-ray.

“The following morning, around 11 o’clock, about 26 or 27 hours later, she texted me and asked me if I could take her to a doctor’s appointment that afternoon,” Mann said. “I immediately called her, and I could tell when I talked to her that she was in distress.”

“We all thought, ‘Oh, it’s just the flu.'”

Mann-O’Brien was having chest pains and difficulty breathing. Her mother raced to her house and took her to the ER, where she was immediately intubated. Pneumonia, an accumulation of fluid in the lungs, brought on by the flu had caused her blood oxygen content to plummet.

“She had double pneumonia, a complete whiteout,” Mann said, meaning both lungs had fluid in them.

Four days later complications began. Mann-O’Brien was rushed by helicopter to a hospital in Kansas City, Missouri, where she was put on an ECMO machine, a device that essentially serves as the patient’s heart and lungs. Her pneumonia abated, but sepsis, in combination with a fungal infection in her small intestine, had caused irreparable damage, and Mann-O’Brien died on April 5, 2012.

Delisah Revell holds her 10-month-old daughter Kelce, who is being treated in the emergency room for the flu in Thomaston, Georgia. "Once I saw how high her fever was and the crying and she was irritable I brought her in. I'm kind of nervous. I heard how bad it is and I didn't want to take any chances," said Revell. David Goldman/AP Photo

For a long time, holidays were the hardest. Mann had taken great pleasure in planning special meals with her daughter, and they had ambitions to travel more—grandmother, mother and daughter—when Mann-O’Brien’s youngest was old enough.

“I feel robbed of those memories we would have made, but I hold dear to my heart those I do have,” Mann wrote in an email. “She was the most wonderful friend and daughter!”

Six years later, Mann sees people suffering through what she did and can hardly stand to watch the news. She founded the nonprofit Kendra’s Legacy Foundation in 2013 to advocate for flu awareness, education and immunization, and is also a member of Families Fighting Flu, a national organization raising flu awareness.

“I think a lot of people were just exactly like we were before Kendra got sick,” Mann said. “We all thought, ‘Oh, it’s just the flu.'”


It is far too easy to say “just the” flu. Influenza does its deadliest work mostly out of the public eye, in distant countries where it emerges from pigs or fowl freshly virulent and alien to human immune systems, or in the distant past, like the Spanish Flu of 1918, which killed an estimated  50 million people. In reality, there is no “just the” flu. The flu virus is complex and difficult to constrain, due to a number of unique abilities which work in concert.

“Flu is as diverse and changeable a virus against which a licensed vaccine exists today,” said Dr. Philip Dormitzer, vice president and chief science officer for viral vaccines at Pfizer. (The pharmaceutical titan does not market a flu vaccine). The reason why lies in the virus’ design.

All viruses require a cell to replicate, be that a bacterium or your own cells. A virus infects a human by infiltrating a cell via special proteins on its outer coat, and once inside, it inserts its own genetic blueprint into the cell, essentially turning it into a virus factory. The flu virus is an RNA virus, meaning it carries its RNA into a cell to use in replication.

The flu virus is already very diverse, and making matters worse, RNA viruses also mutate faster than DNA viruses. Furthermore, flu viruses are segmented, meaning that they can pass along only a fraction of their genome, making them even more variable.

“It’s analogous to mating in mammals or other higher organisms, where you have chromosome re-sorting increasing the genetic diversity of the descendants, ” Dormitzer said.

What this means is that the proteins in the virus’ membrane, which trick the cell into accepting the virus and then letting it back out, can change rapidly, making it difficult for the immune system and vaccines to keep up. These proteins, hemagglutinin and neuraminidase, are so crucial that they are also how we name each strain. H3N2, the virus that is making this year’s flu season so severe, contains a subtype 3 hemagglutinin protein and a subtype 2 neuraminidase protein in its membrane.

According to Dormitzer, the most important factor for determining both immunity against flu, and a critical clue as to how severe the infection can be, is the specific variant of hemagglutinin present.

“That is the main molecule that the virus uses to latch on to cells, and to breach their membranes so the virus can get into the cell and start its replication cycle,” Dormitzer said. Neuraminidase is what allows newly made viruses to escape the cell so that they can infect other cells.

The constant variation in these outer proteins is known as antigenic drift, and it is the main reason why vaccines do not provide 100 percent immunity. Vaccines are designed to protect against the various strains most likely to be common during flu season. According to the Centers for Disease Control and Prevention (CDC), more than 100 national influenza centers perform year-round surveillance of the virus, and this data is then used to decide what strains to vaccinate for.

This flu season, the antigenic drift was particularly bad, leading to a vaccine that the CDC says has been 36 percent effective against influenza this year. Compounding the problem is that the main type of flu going around is a particularly brutal specimen.

“Of the strains out there that regularly circulate, H3N2 tends to be the nastiest,” Dormitzer said.


Lack of vaccination and a particularly virulent strain may have combined to create this especially severe flu season. In case after case, deaths seem to be caused mainly by pneumonia and sepsis.

“Sometimes you can get complications of the flu, such as secondary bacterial pneumonia, that can be very, very frightful,” said Dr. Aaron Glatt, spokesperson for the Infectious Disease Society of America and chairman of the department of medicine and hospital epidemiologist at South Nassau Communities Hospital in Oceanside, New York.

The body’s response to infection can cause sepsis. According to Glatt, when presented with an infection the body can have what is called an “inflammatory response.” As the body releases chemicals to help fight the infection, these can spread throughout the body, causing widespread damage.

“If it’s severe enough, that’s what we would call septic shock,” Glatt said. “You can drop your blood pressure, you’re not oxygenating well, you’re behind in fluids, and you begin to shut down ‘non-critical’ parts of your body like your kidney and your liver, and they’re going to be in a vicious worsening cycle. As you get sicker, you keep on getting sicker.”

It is impossible to know for sure how any given person will respond to any given flu infection.

“Every individual person is going to react differently to it,” Glatt said. “One person may get a relatively mild illness, and another person may get much, much more severe.”

There is only one recommendation: vaccinate.

“That’s the only real, well-documented, proven way to prevent, to a certain extent, influenza infection,” Glatt said. “It’s not perfect, it doesn’t work 100 percent of the time by any means … but at the same time, it is clearly the only recommended thing to prevent flu at the time. And I don’t understand why people don’t follow the recommendations of every single professional organization.”


A medical assistant administers the flu vaccine to a patient in Seattle Ted S. Warren/AP Photo

Vaccination promotion is a key cause of Families Fighting Flu (FFF), the national nonprofit formed by those whom the virus has left behind. Families who lost children to flu were determined to push for a universal recommendation of vaccination, which the CDC passed in 2010.

That same year, Serese Marotta joined FFF, a year after losing her 5-year-old son in the 2009 H1N1 pandemic. Marotta, who is now the group’s COO, said that FFF’s goal is to inform the general public about the seriousness of the flu. In deadly seasons like this one, the “just the” attitude may be just as dangerous as the virus’ H and N profile.

“People for the most part, and I was one of them, we don’t really understand the dangers of flu,” Marotta said. “Because so often we have heard: ‘Oh, it’s just the flu.’”

Marotta also understands the reluctance to get vaccinated, or the frustration at its seemingly low efficacy. In fact, she understands these frustrations better than most, as her son was vaccinated the year he died. The vaccine that year did not include the H1N1 strain.

To suffer such a loss but still campaign for vaccination shows the importance of embracing an imperfect answer to a problem which currently lacks a perfect one.

“Here’s where I go with it,” Marotta said. “If you don’t get a flu shot, you have zero percent protection. I’m not a gambling person, but I would say that any percentage is better than zero.” Immunization does not just protect yourself, Marotta points out; it helps to protect those around you, as well.

For her part, although it is impossible to know for sure, Joan Mann believes fervently that a flu vaccine would have saved her daughter’s life. For now, all she can do is continue to provide vaccinations and information via the Kendra’s Legacy Foundation, and share Kendra’s story.

“It’s pretty much an obligation,” Mann said. “I want people to realize how dangerous this horrible, deadly virus is.”

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