COVID-19, a strain of the coronavirus, was officially declared a pandemic—the global outbreak of a disease—by The World Health Organization on Wednesday, March 11. Today we take a look at a few other extreme pandemics in our history.

The 1918 influenza pandemic was caused by an H1N1 virus with genes of an avian origin. There is not a general consensus of exactly where the disease originated, but what can be agreed on is how it sweeped the entire world from 1918-1919. The first identified case in the United States was in military personnel in spring of 1918. An estimation of approximately 500 million people, one-third of the world’s population, became infected with this virus. It is estimated that there were at least 50 million deaths worldwide, 675,000 being in the United States. The mortality rates were high in people ages 20-40 years old, 65 years and older and younger than 5 years old. There was no vaccine for the virus and no antibiotics to treat the secondary bacterial infections. Worldwide actions taken were isolation, quarantine, good personal hygiene, use of disinfectants, and limitations of public gatherings, very similar to the actions we are taking today with the Coronavirus.

In February of 1957, another influenza A (H2N2) virus developed in East Asia, provoking a pandemic. First reported in Singapore in February 1957, Hong Kong in April 1957, and in coastal cities in the United States in the summer of 1957, this virus contained three different genes from an H2N2 virus that came from an avian influenza A virus, including the H2 hemagglutinin and the N2 neuraminidase genes. The estimated number of deaths worldwide was 1.1 million and 116,000 in the United States. The outbreak was associated with a variation in susceptibility and course of illness. Some infected individuals experienced minor symptoms such as cough and mild fever, whereas others experienced life-threatening complications such as pneumonia. Fortunately, the rapid development of a vaccine and the availability of antibiotics to treat secondary infections reduced the spread and mortality rates of the pandemic. Doctor Maurice Hilleman made a critical observation that the two key proteins in the flu virus undergo slight changes between seasons. This insight prompted his recognition of the necessity of yearly flu vaccinations. 

A pandemic emerged in 1968 caused by an influenza A (H3N2) virus composed of two genes from an avian influenza A virus, including a new H3 hemagglutinin, but also contained the N2 neuraminidase from the 1957 H2N2 virus. The virus emerged in July in Hong Kong. The first reported case in the United States was in September of 1968. It is estimated that there were 1 million worldwide deaths and approximately 100,000 in the United States. The highest levels of mortality were associated with infants and the elderly. The virus was extremely contagious, just like the Coronavirus, which contributed to the widespread of it. Within two weeks of the disease’s emergence in Hong Kong, some 500,000 cases of illness were reported. The pandemic took place in two different waves. In the majority of places the latter wave caused a greater number of deaths than the first one. The symptoms included chills, fever, and muscle pain and weakness. These symptoms usually lasted between four to six days. A vaccine was developed against the virus, but it only became available after the peak of the pandemic in many countries.