2017-2018 — Winter (March 2018 end) Influenza (primarily H3N2) ~80,000
— 80,000 Branswell. “‘The problem…of seasonal flu’: Beware this winter’s virus.” Stat News, 1-8-2018.
Narrative Information
Branswell: “People in public health hate H3N2 flu seasons, like the one gripping most of North America right now. So do folks who work in hospitals and in the care facilities that look after the elderly. To put it flatly, H3N2 is the problem child of seasonal flu. It causes more deaths than the other influenza A virus, H1N1, as well as flu B viruses. It’s a quirky virus that seems, at every turn, to misbehave and make life miserable for the people who contract it, the scientists trying to keep an eye on it, and the drug companies struggling to produce an effective vaccine against it.
“‘H3 viruses dwarf the contribution of H1 to overall epidemic burden [of influenza] in terms of hospitalizations, care facility outbreaks, deaths. I think uniformly in public health we dread H3N2 epidemics over and above those due to H1N1,” said flu expert Dr. Danuta Skowronski, an epidemiologist with the British Columbia Center for Disease Control….
“H3N2 viruses first emerged during the pandemic of 1968 — the so-called Hong Kong flu. That means people who are over 50 had their flu immune response set by other viruses, either the H2N2 viruses that circulated from 1957 to 1968, or H1N1 viruses that circulated from 1918 to 1957 and are ancestors of the H1 viruses still circulating today.
“Combine with that the fact that people over 50 — and especially people in their 70s, 80s, and beyond — are less healthy and have less robust immune systems. They may have health conditions like diabetes, chronic obstructive pulmonary disease, or heart disease. They have a harder time shaking off an illness like the flu.
“It’s increasingly common to hear people complain about the sometimes suboptimal performance of influenza vaccine. And mostly that’s because of the H3N2 component of the vaccine, which protects against either four (both influenza A viruses and both influenza B viruses) or three (the two As and one B) viruses. ‘We don’t have a flu vaccine problem so much as we have an H3N2 vaccine problem,” Belongia said.
“He and colleagues published a meta-analysis in 2016 that combined data from flu vaccine effectiveness studies done between 2004 and 2015. On average, the H3N2 component of the vaccine protected about 33 percent of the time. The component that protects against H1N1 was nearly twice as effective. At least part of the reason why the H3N2 component of the vaccine doesn’t work that well is because these viruses don’t grow very well in eggs, the main production method for flu vaccine….” (Branswell, Helen. “‘The problem child of seasonal flu’: Beware this winter’s virus.” Stat News, 1-8-2018.)
CDC: “What was the 2017-2018 flu season like?
“The 2017-2018 influenza season was a high severity season with high levels of outpatient clinic and emergency department visits for influenza-like illness (ILI), high influenza-related hospitalization rates, and elevated and geographically widespread influenza activity for an extended period. In 2017, CDC began using new methodology to classify seasonal severity and applied the methodology to the 2003-2004 through 2016-2017 seasons. The 2017-18 season was the first season to be classified as a high severity across all age groups.
“When did the 2017-2018 flue season peak?
“During the 2017-2018 season, influenza-like-illness (ILI) activity began to increase in November, reaching an extended period of high activity during January and February nationally, and remained elevated through the end of March. ILI peaked at 7.5%, the highest percentage since the 2009 flu pandemic, which peaked at 7.7%. Influenza-like illness (ILI) was at or above the national baseline for 19 weeks, making the 2017-2018 season one of the longest in recent years.
“How many people died from flu during the 2017-2018 season?
“While flu deaths in children are reported to CDC, flu deaths in adults are not nationally notifiable. In order to monitor influenza related deaths in all age groups, CDC tracks pneumonia and influenza (P&I)-attributed deaths through the National Center for Health Statistics (NCHS) Mortality Reporting System. This system tracks the proportion of death certificates processed that list pneumonia or influenza as the underlying or contributing cause of death. This system provides an overall indication of whether flu-associated deaths are elevated, but does not provide an exact number of how many people died from flu.
“During the 2017-2018 season, the percentage of deaths attributed to pneumonia and influenza (P&I) was at or above the epidemic threshold for 16 consecutive weeks. During the past five seasons, the average number of weeks this indicator was above threshold was 11 (range of 7 to 15 weeks). Nationally, mortality attributed to P&I exceeded 10.0% for four consecutive weeks, peaking at 10.8% during the week ending January 20, 2018.
“As it does for the numbers of flu cases, doctor’s visits and hospitalizations, CDC also estimates deaths in the United States using mathematical modeling. CDC estimates that from 2010-2011 to 2013-2014, influenza-associated deaths in the United States ranged from a low of 12,000 (during 2011-2012) to a high of 56,000 (during 2012-2013). Death certificate data and weekly influenza virus surveillance information was used to estimate how many flu-related deaths occurred among people whose underlying cause of death on their death certificate included respiratory or circulatory causes….
“How many children died from flu during the 2017-2018 season?
“As of August 25, 2018, a total of 180 pediatric deaths had been reported to CDC during the 2017-2018 season. This number exceeds the previously highest number of flu-associated deaths in children reported during a regular flu season (171 during the 2012-2013 season). Approximately 80% of these deaths occurred in children who had not received a flu vaccination this season…. Since flu-associated deaths in children became a nationally notifiable condition in 2004, the total number of flu-associated deaths among children during one season has ranged from 37 (during the 2011-2012 season) to 180 (during the 2017-18 season, as of August 11); this excludes the 2009 pandemic, when 358 pediatric deaths from April 15, 2009 through October 2, 2010 were reported to CDC….: (CDC. Summary of the 2017-2018 Influenza Season. 8-31-2018.)
Strobe (AP): “New York — An estimated 80,000 Americans died of flu and its complications last winter [2017-2018] the disease’s highest death toll in at least four decades. The director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, revealed the total in an interview Tuesday night with The Associated Press.
“Flu experts knew it was a very bad season, but at least one found size of the estimate surprising. ‘That’s huge,’ said Dr. William Schaffner, a Vanderbilt University vaccine expert. The tally was nearly twice as much as what health officials previously considered a bad year, he said.
“In recent years, flu-related deaths have ranged from about 12,000 to — in the worst year — 56,000, according to the CDC. Last fall and winter, the U.S. went through one of the most severe flu seasons in recent memory. It was driven by a kind of flu that tends to put more people in the hospital and cause more deaths, particularly among young children and the elderly.
“The season peaked in early February. It was mostly over by the end of March, although some flu continued to circulate. Making a bad year worse, the flu vaccine didn’t work very well. Experts nevertheless say vaccination is still worth it, because it makes illnesses less severe and save lives.
Sources
Branswell, Helen. “‘The problem child of seasonal flu’: Beware this winter’s virus.” Stat News, 1-8-2018. Accessed 9-28-2018 at: https://www.statnews.com/2018/01/08/flu-virus-h3n2/
Centers for Disease Control and Prevention. Summary of the 2017-2018 Influenza Season. 8-31-2018. Accessed 9-28-2018 at: https://www.cdc.gov/flu/about/season/flu-season-2017-2018.htm
Strobbe, Matt (Associated Press). “CDC: 80,000 people died of flu last winter in U.S., highest death toll in 40 years.” 9-26-2018. Accessed 9-28-2018 at: https://www.statnews.com/2018/09/26/cdc-us-flu-deaths-winter/
Tribune Media Wire. “’Nobody Ever Thinks It Will Happen To Them:’ 27-Year-Old Woman Dies After Catching Flu.” 5NewsOnline, 1-18-2018. Accessed 1-18-2018 at: http://5newsonline.com/2018/01/18/nobody-ever-thinks-it-will-happen-to-them-27-year-old-woman-dies-after-catching-flu/