The ongoing coronavirus pandemic is already one of the deadliest in history, having killed more than 4.5 million people worldwide.COVID-19 was first identified in 2019, in the Chinese city of Wuhan. It quickly spread all over the world, with the World Health Organization (WHO) declaring a pandemic in March 2020.As COVID-19 spread across the globe, so did conspiracy theories about its origins and characteristics, alarming public health experts and policymakers alike.Here are some of the most popular coronavirus conspiracy theories.U.S. Military Deployed COVID-19As many in the West sought to blame official Beijing for the spread of COVID-19, prominent Chinese officials started pushing a conspiracy theory of their own.According to Cornell University, Chinese foreign ministry spokesman Zhao Lijian first alleged on social media that "it’s possible that the US military brought the virus to Wuhan."The conspiracy theory is reportedly popular in China, with many believing that the U.S. government deliberately deployed the virus to devastate the Chinese economy.The theory has spread like wildfire on social media and in the U.S.5G Is Causing Coronavirus5G is the fifth-generation wireless technology standard. Faster and more reliable than the existing 4G LTE network, 5G is expected to fuel a new technological revolution.According to some conspiracy theorists, however, 5G is causing COVID-19. Obviously, viruses cannot travel on mobile networks, but that hasn't stopped the conspiratorial-minded -- including some celebrities -- to spread this bizarre theory.As Cornell noted, "it is biologically impossible for viruses to spread using the electromagnetic spectrum. The latter are waves/photons, while the former are biological particles composed of proteins and nucleic acids."Bill Gates Is To BlameSeveral popular conspiracy theories about COVID-19 involve billionaire philanthropist and Microsoft co-founder Bill Gates.Exceptionally popular on the furthest fringes of the American right -- among QAnon followers and diehard MAGA Republicans -- one Gates-related conspiracy theory claims that coronavirus is part of his plan to vaccinate the world's population.Conspiracy theorists think Gates is not trying to vaccinate people out of the goodness of his heart, but because he wants to implant digital microchips in every living human being.In fact, some believe Gates actually caused the pandemic to advance his agenda.Coronavirus Isn't RealSome believe coronavirus is no worse than the seasonal flu.COVID-19, conspiracy theorists claim, doesn't even exist: It's just an elaborate plot by the global elite to enslave the population under the guise of fighting a deadly virus.All available data shows that coronavirus is much worse than the flu.According to the Centers for Disease Control and Prevention(CDC), though there are some similarities between influence and COVID-19, the latter far more frequently results in severe illness, serious complications, and death.