The world has a big COVID-19 problem. But just how big? Each infected person carries between one billion and one hundred billion virus particles at the peak of infection. This equates to no more than 0.1 milligrams of virus per infected person—about the same as a single poppy seed. Multiplying by the number of infected people around the world, researchers estimate that our COVID-19 problem can be chalked up to between 0.1 kilograms and 10 kilograms of virus.