Previous efforts to estimate the burden of fatigue-related symptoms due to long COVID have a very high threshold for inclusion of cases, relative to the proposed definition from the World Health Organization. In practice this means that milder cases, that may be occurring very frequently, are not included in estimates of the burden of long COVID which will result in underestimation. A more comprehensive approach to modelling the disease burden from long COVID, in relation to fatigue, can ensure that we do not only focus on what is easiest to measure; which risks losing focus of less severe health states that may be more difficult to measure but are occurring very frequently. Our proposed approach provides a means to better understand the scale of challenge from long COVID, for consideration when preventative and mitigative action is being planned.