We consider an epidemic in a strongly correlated biological system, where the influence of the environment on the individual state and immune response of the infected is decisive. This leads to the 3D Lotka-Volterra system and explains the existence of sustained epidemic waves that are absent in the conventional SIRS model. Taking the biological correlations into account turns the population into a single organism, as a result of which the course of the epidemic reproduces all phases of an individual's infection. We argue that strong correlation effects are critical in shaping the COVID-19 epidemic, which is adequately described by the 3D Lotka-Volterra equations.