Incidence of a variant (IMAGE) Tokyo Metropolitan University Caption Simulation on a network of numbers of susceptible (S), infected (I) and recovered (R) from a pandemic and its variant (I’, R’) over time. At t=21, a variant was added. Credit Tokyo Metropolitan University Usage Restrictions Can be reused with credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.