A look back at the 2018/2019 Flu Season

According to a recent study by the renowned journal, The Lancet, more than half a million people die each year worldwide as a result of influenza-related respiratory diseases. We decided to take a closer look at how the flu impacts European and North American countries as they have recently endured the height of the flu season.

The symptoms of a “real flu” differ from those of a flu-like infection, primarily in the sudden onset of the disease with indicators such as high fever, chills and severe pain in the limbs.   

“Even though the highly contagious pathogens can be transmitted through the air from person to person in viral influenza, contaminated surfaces also play a major role in the spread of the virus. Hand hygiene is therefore incredibly important to the prevention of infections. According to the WHO, virucidal hand disinfectants must be used only to a limited extent for hygienic hand disinfection. This is in accordance with the 5 moments for hand hygiene in order to effectively eradicate these enveloped viruses and Break the Chain of Infection.”

Dr. Andreas Glöckner, MD.

The flu often leads to complications and serious consequences, especially for anyone with a weakened immune system, children and the elderly. The disease is primarily caused by influenza viruses A and B, which are capable of constantly changing their molecular structure, and thus cannot be recognized and treated by the immune system. 

This ability to change is noted in what is likely the best-known influenza pandemic in recent history, dating back just 100 years. Between 1918 and 1920, the Spanish Flu claimed at least 25 million lives worldwide. This severe outbreak was caused by variants of the subtype A H1N1. According to a study by Worobey and colleagues, the virus had the H1 of the “normal” flu and the N1 of avian flu. [1] Type H1 was rare in influenza viruses in the last decade of the 19th century but gradually replaced the H3 strain from 1905 onwards. Young adults between the ages of 20 and 30 succumbed to this Spanish Flu because they had never encountered type 1 hemagglutinin (H1) during their childhood and therefore were likely never able to develop any natural immunity.

Influenza in Europe

100 years later, the flu is causing over 500,000 deaths worldwide each year. [2] The extent to which this affects Europe has been investigated by the European Centre for Disease Prevention and Control (ECDC). As part of weekly updates, the institution reports in detail on the course and virus types of influenza for all European countries. With the beginning of summer in the Northern Hemisphere, the ECDC declared the current 2018/2019 flu season officially over on the 19^th of May. The figures show that activity was less intense than last season with fewer infections and deaths. [3] However, it should be noted that the 2017/2018 flu season was exceptionally strong in terms of infection and death rates, exceeding all previous years. When looking at the virus responsible for the infection, we see that virus type A dominated in this influenza season whereas the previous season was dominated by virus type B. 

A look across the pond

As a counterpart to the ECDC in Europe, the Centers for Disease Control and Prevention (CDC) of the U.S.A, monitors and documents influenza activities within the country. Here too, the 2018/2019 influenza season recently ended and parallels the European cycle. There were 40,000,000 influenza cases in the United States this flu season, which is nearly 20 percent below the previous year. [4] The approximately 60,000 flu-related deaths in 2018/2019 are also lower than in 2017/2018, where the CDC recorded 78,000 deaths.[5] Looking back to 2010/2011, the flu epidemic in 2017/2018 was second worst in terms of hospital admissions behind last year’s extremely high rate in North America. However, the recently ended season was the worst in terms of duration. At 21 weeks it broke the record of 2014/2015, which lasted 20 weeks. [6]

“This season has been record-breaking in terms of duration.”

Kristen Nordlund, CDC spokeswoman.

We can see that the 2018/2019 flu season in the Northern regions was dominated by the influenza A virus and was less extreme than the previous season in terms of infections and deaths, but lengthy nonetheless. The Robert Koch Institute in Germany registered about 180,000 influenza cases this season, significantly higher than the years prior to 2017/2018.[7]

Looking forward, concerning data was provided in mid-June by the Department of Health in Australia, where the flu season is just beginning. They reported more than 75,000 influenza infections in the first week of June, and the experts are preparing for a dramatic flu season on the continent.[8]

Prevention beats infection

Thorough hand hygiene is an important measure to to effectively protect against influenza,  in addition to a vaccination. Frequently touched objects in public areas are true “hot spots” for these pathogens, and can be the starting point for contact infections with influenza viruses. 

Scientific studies consistently confirm the effectiveness of proper hand hygiene measures to prevent influenza infections. A study carried out in 2015 specifically stated that improved hygiene behaviour in educational establishments can reduce cases of influenza in children.[9] A further study in the Journal Medicine from 2016 confirms the positive effect of careful hand hygiene on reducing seasonal influenza illnesses.[10] Although there are many ways to protect yourself and those around you from the flu, proper and regular hand hygiene is one of the easiest and most effective ways to prevent infection.  

Source:

[1] Worobey, Michael, et al. “Questioning the evidence for genetic recombination in the 1918″ Spanish flu” virus.” Science 296.5566 (2002): 211-211.

[2] Iuliano, A. Danielle, et al. “Estimates of global seasonal influenza-associated respiratory mortality: a modelling study.” The Lancet 391.10127 (2018): 1285-1300.

[3] online unter: http://flunewseurope.org/

[4] online unter: https://www.cdc.gov/flu/index.htm

[5] Estimated Influenza Illnesses, Medical visits, Hospitalizations, and Deaths in the United States — 2017–2018 influenza season

[6] online unter: https://edition.cnn.com/2019/04/19/health/flu-longest-season-cdc-bn/index.html

[7] Robert Koch-Institut – Arbeitsgemeinschaft Influenza

[8] Australian Influenza Surveillance Report – 2019 Influenza Season in Australia, online unter:https://www.health.gov.au/internet/main/publishing.nsf/Content/cda-surveil-ozflu-flucurr.htm#current

[9] Torner, Núria, et al. “Effectiveness of non-pharmaceutical measures in preventing pediatric influenza: a case–control study.” BMC public health 15.1 (2015): 543.

[10] Liu, Mingbin, et al. “Protective effect of hand-washing and good hygienic habits against seasonal influenza: a case-control study.” Medicine 95.11 (2016).