World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus officially declared COVID-19, the disease caused by the novel coronavirus, a pandemic on Wednesday. COVID-19 had previously been designated as a global health emergency in January after the number of cases of the virus soared in China. From epidemic to pandemic An epidemic occurs when a disease affects many people with the number of cases above what would be normally expected. A pandemic occurs when an epidemic spreads across the world and affects a large number of people. WHO officials have carefully avoided directly calling the COVID-19 outbreak as a pandemic until today. They have come close, though, with Ghebreyesus stating on Monday that "the threat of a pandemic has become very real." Image source: Getty Images. Now, however, the sheer scale of the numbers has prompted WHO to declare COVID-19 as a pandemic. There have been more than 120,000 people in at least 114 countries who have been infected by the novel coronavirus. So far, more than 4,000 individuals across the world have died from COVID-19. What's next? Governments and private companies are scrambling to develop vaccines and treatments for COVID-19. Gilead Sciences (NASDAQ: GILD) appears to be in the lead position in testing a potential antiviral treatment for the disease. The big biotech is currently conducting two late-stage clinical studies evaluating remdesevir in treating COVID-19. Several drugmakers are also rushing to test experimental COVID-19 vaccines. In the meantime, health experts recommend washing hands with soap and water for at least 20 seconds and limiting contact with others to reduce the chances of exposure to the coronavirus. 10 stocks we like better than Gilead SciencesWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Gilead Sciences wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of December 1, 2019 Keith Speights owns shares of Gilead Sciences. The Motley Fool owns shares of and recommends Gilead Sciences. The Motley Fool has a disclosure policy.Source