Written by Staff Writer

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A single flu season doesn't define a whole lifetime. But every year, thousands of people die from the flu, or from something related to it. In 2017-18, according to the Centers for Disease Control and Prevention, that number was 17,127, making it the most recent flu season to record elevated numbers of deaths.

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Deaths from the flu are increasing sharply: In the last 12 months, there were more than 2,000 pediatric deaths -- up 80% from the previous year.

The US Health and Human Services announced Friday that they were stepping up their flu preparations, preparing a new stockpile of Tamiflu, which is in high demand after a wave of flu cases in 2018.

Last year, the CDC issued a "public health emergency of international concern" after the emergence of the new H5N1 virus -- a bird flu strain that is especially deadly for poultry. This resulted in a global surge in sales of Tamiflu, the prescription antiviral drug, and other products that combat bird flu and other flu strains.

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"We should take (Pandemics) seriously. If you are a healthy person, it is probably not the biggest health threat you face. But if you are a baby or a senior citizen, or if you have certain chronic conditions, it could be very serious," Dr. Jim Smith, director of the Office of Health Strategy at the CDC, said in a briefing with reporters last year.

But as much as we learn about SARS and other killer viruses, there's still a lot we don't know about more frightening viruses. When the SARS virus made its way into people in 2003, the World Health Organization declared it an international health emergency.

A second series of pandemics, known as the "Nepal effect," occurred two years later when people got sick in Nepal and the government and local authorities did not take adequate measures to prevent a second wave.

In 2017, a new and emerging virus (known as the "SARS 2.0") appeared in the Middle East and North Africa. As it spread, it has yet to be fully described or fully categorized by the CDC.

The coronavirus, also known as MERS, is a leading suspect in at least one of the most recent Middle East outbreaks -- the largest and deadly in recent years, according to the CDC.

An MERS coronavirus case was also reported in the United States last year. Hospital records for the patient who died in the United States contain the following chilling note: "Previous exposure to Chinese China strains of MERS."

Although the overwhelming majority of coronavirus cases are in the Middle East, in recent years SARS's descendants have also spread around the world.

The infection is known as MERS-CoV or Middle East Respiratory Syndrome, a coronavirus that originated in camels. It was first detected in the Arabian Peninsula in 2012 and has since spread to other continents, mostly the Middle East.

The virus has killed more than 2,000 people and sickened more than 10,000. MERS-CoV is believed to infect about 2% of people who have been infected, and is usually mild, with short-term flu-like symptoms. But among some people, it has become severe enough to kill. (Other coronaviruses -- such as the common cold -- cause a significantly smaller number of deaths.)

Cases of MERS have also been reported in hospitals in Europe, France, India, Italy, Malaysia, South Korea, Switzerland, and the United Kingdom. The Chinese mainland has seen two outbreaks, one in 2014 and the other in 2016. (In 2016, some of the cases in the United States were also related to the Middle East outbreak.)

Every year, the WHO declares an international health emergency (IHE) based on a specific new virus or a terrorist threat, depending on the circumstances.

Some of the more memorable IHEs from recent years include Ebola, Ebola Zaire (Zaire), HIV, polio, and SARS.