A century ago, hospitals reported an average of 100 patient deaths a day attributed to influenza, infecting about 500 million people worldwide in 1918. While technological and scientific advancements allow for better flu detection, tracking and treatment, health experts said flu pandemics are likely to occur again, according to USA Today.
Here are four things to know:
1. Fifty million people — about one out of every 30 humans on the planet — died during the 1918 flu pandemic. A strain of the H1N1 virus, which is genetically linked to birds, caused the pandemic.
"Influenza viruses, with the vast silent reservoir in aquatic birds, are impossible to eradicate," the World Health Organization said. "With the growth of global travel, a pandemic can spread rapidly globally with little time to prepare a public health response."
2. A pandemic could resurface again if a strain mutated or developed directly from an animal flu virus, the CDC said. The agency cited the lack of a worldwide vaccine and humans' weak immunity as the major contributing factors for a potential pandemic.
"A global influenza pandemic is No. 1, 2, 3, and 4 on our list of the most-feared public health crises," Michael Osterholm, PhD, director of the Minneapolis-based University of Minnesota's Center for Infectious Disease Research and Policy, told USA Today.
3. However, health officials can deploy numerous safeguards that did not exist 100 years ago. For instance, scientists can implement systems to detect potential outbreaks worldwide, concoct vaccines faster and provide better antiviral drugs than previous generations due to readily evolving technology.
4. During the 2017-18 flu season, about 80,000 people died from the flu, while 900,000 were hospitalized. For the 2018-19 flu season, the CDC recommends everyone 6 months and older receive their flu shot by the end of October.