https://www.scientificamerican.com/article/lessons-from-past-outbreaks-could-help-fight-the-coronavirus-pandemic1/

On March 11 the World Health Organization officially designated the novel coronavirus outbreak a pandemic. Defined as the worldwide spread of a new disease, such a declaration is the first to be made since the 2009 H1N1 swine flu. As of this writing, there have been approximately 336,000 confirmed cases of the new disease, called COVID-19, resulting in more than 14,600 deaths worldwide.

Although a coronavirus—a family of viruses that cause illnesses ranging from the common cold to severe acute respiratory syndrome (SARS)—had not previously triggered a pandemic, this is not the first time we have seen the global transmission of a serious disease. Studying past outbreaks can help scientists better estimate the trajectory of COVID-19 and identify the best measures to slow its spread.