Tuesday, February 13, 2018

Pediatrics: Influenza Associated Pediatric Deaths - US 2010–2016

CDC FluView Week 5


Since reporting became mandatory after the high-severe flu season of 2003-04, yearly pediatric influenza deaths have ranged from a low of 35 during the 2011-2012 flu season to a high of 282 during the 2009—2010 H1N1 pandemic.
As tragic as the 2009 pandemic tally was, the CDC estimated that the number of pediatric deaths in the United States probably ranged from 910 to 1880, or anywhere from 3 to 6 times higher than reported.

Even during non-pandemic seasons, the CDC believes the officially reported numbers likely understate the true number of pediatric deaths due to influenza by half.

In 2013, in Pediatrics: Influenza-Associated Pediatric Deaths, we looked at a study by Karen K. Wong et al. called Influenza-Associated Pediatric Deaths in the United States, 2004–2012 that analyzed the first 8 years of data on pediatric flu-related deaths. 
They reported the median age was 7 years, that 35% of children died before hospital admission, and of 794 children with a known medical history, 43% had no high-risk medical conditions.
We've a new study, just published in the journal Pediatrics, that looks at pediatric flu-related deaths during the next 6 post-pandemic flu seasons (2010–2016) and finds the median age has dropped to 6 years, and the percentage of kids with no high-risk medical conditions has jumped to 50%.

First a link and some excerpts from the Abstract, followed by a summary from the CDC, and then I'll return with a postscript.
Influenza-Associated Pediatric Deaths in the United States, 2010–2016 
Mei Shang, Lenee Blanton, Lynnette Brammer, Sonja J. Olsen, Alicia M. Fry


BACKGROUND: Influenza-associated pediatric deaths became a notifiable condition in the United States in 2004.

METHODS: We analyzed deaths in children aged < 18 years with laboratory-confirmed influenza virus infection reported to the Centers for Disease Control and Prevention during the 2010–2011 to 2015–2016 influenza seasons. Data were collected with a standard case report form that included demographics, medical conditions, and clinical diagnoses.
RESULTS: Overall, 675 deaths were reported. The median age was 6 years (interquartile range: 2–12). The average annual incidence was 0.15 per 100 000 children (95% confidence interval: 0.14–0.16) and was highest among children aged < 6 months (incidence: 0.66; 95% confidence interval: 0.53–0.82), followed by children aged 6–23 months (incidence: 0.33; 95% confidence interval: 0.27–0.39). Only 31% (n = 149 of 477) of children aged ≥6 months had received any influenza vaccination.
Overall, 65% (n = 410 of 628) of children died within 7 days after symptom onset. Half of the children (n = 327 of 654) had no preexisting medical conditions. Compared with children with preexisting medical conditions, children with none were younger (median: 5 vs 8 years old), less vaccinated (27% vs 36%), more likely to die before hospital admission (77% vs 48%), and had a shorter illness duration (4 vs 7 days; P < .05 for all).
CONCLUSIONS: Each year, influenza-associated pediatric deaths are reported. Young children have the highest death rates, especially infants aged < 6 months. Increasing vaccination among children, pregnant women, and caregivers of infants may reduce influenza-associated pediatric deaths.
Accepted December 18, 2017.
Study of Flu-Related Deaths in Children Shows Healthy Children at Risk
February 12, 2018 – A CDC study published in the journal Pediatrics shows just how vulnerable U.S. children are to the flu each year. The study, titled “Influenza-Associated Pediatric Deaths in the United States, 2010-2016,” analyzed reported flu-related deaths in children younger than 18 over the course of six flu seasons from October 2010 through September 2016.
Results showed that half of flu-related deaths occurred in otherwise healthy children, 27% of whom had not received a seasonal flu vaccination. This is an update to the 2013 Wong, et al paper published in Pediatrics in 2013 that showed similar findings regarding overall flu risk in children.
One notable difference, however, was the increase in flu-related deaths among healthy children. Previously, fewer than 40% of children who died had no underlying high-risk medical conditions.

These findings also show antiviral treatment was only given in about half of all pediatric flu deaths. CDC recommends that flu antiviral drugs be started as soon as possible when young children and children with high-risk conditions are suspected of having the flu.

During 2010-2016, young children continued to be at the greatest risk for flu-associated pediatric deaths. The findings show that vaccination coverage was low among these children. This supports CDC’s recommendation that all children 6 months of age and older should receive a flu vaccination each year. Pregnant women and caregivers of infants should also get vaccinated to help protect them.

This study stresses how quickly the flu can become life-threatening for children. Nearly two-thirds of children died within seven days of developing symptoms. Over one-third died at home or in the emergency department prior to hospital admission. In fact, children without other medical conditions that would predispose them to serious flu complications were more likely to die before hospital admission.
This is a reminder that parents should seek prompt medical care for young children and children at high risk for flu complications with flu symptoms.

During all six seasons, mortality rates were highest in children younger than 2 years of age. Native Hawaiian/Pacific Islander and American Indian/Alaska Native children were also at higher risk.

The greatest number of pediatric deaths in the study occurred during the 2012-13 season while the fewest occurred during the 2011-12 season. Flu A viruses were associated with the majority of deaths in children (65%), while flu B viruses accounted for 33% of deaths.
Bacterial co-infections were more common among otherwise healthy children than among children with a high-risk medical condition. Clinical complications were reported for 75% of children, with the most common being pneumonia (41%) and sepsis (31%).

While the flu shot isn't always as effective as we'd like - particularly in recent years against  H3N2 - it often works better in children, and the (quadrivalent) vaccine is usually far more effective against both H1N1 and Influenza B.

Less than a year ago, in Pediatrics: Study Shows Flu Shot Reduces Flu Related Pediatric Deaths By Half, we looked at another CDC study which found:
`. . . . flu vaccination reduced the risk of flu-associated death by half (51 percent) among children with underlying high-risk medical conditions and by nearly two-thirds (65 percent) among healthy children.'
With H3N2 still raging, and the potential for seeing a last season surge of either H1N1 or (more likely) influenza B, it isn't too late to get that flu shot for you, or for your child.
But if your child does get sick, it is important to know when you should seek medical help, since early treatment with antivirals can sometimes be lifesaving.
From the CDC's The Flu: A Guide For Parents:
  • Fast breathing or trouble breathing
  • Bluish or gray skin color
  • Not drinking enough fluids (not going to the bathroom or not making as much urine as they normally do)
  • Severe or persistent vomiting
  • Not waking up or not interacting
  • Being so irritable that the child does not want to be held
  • Flu symptoms improve, but then return with fever and worse cough
  • Has other conditions (like heart or lung disease, diabetes, or asthma) and develops flu symptoms, including a fever and/or cough.

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