We explain what is the morbidity or morbidity of a disease and the differences with mortality. In addition, morbidity rates.

Morbidity is the frequency of occurrence of a disease in relation to the population.

What is morbidity?

In epidemiology and statistics, morbidity or morbidity is the proportion of individuals who contract a disease specific to a specific location and time period. That is, it is the frequency of onset of the disease in relation to the population: the higher the morbidity rates of a disease, the greater the number of people affected by it in the considered period.

This term comes from the Latin word morbiditymeaning “sick”, and expressed in percentage terms, is one of the most useful indicators in planning public health strategies, for example, when dealing with an epidemic. Not to be confused with mortality, an entirely different statistical indicator.

It can help you: Health (according to WHO)

morbidity rates

Two different morbidity rates are commonly used, depending on the specific information needed:

  • Prevalence rate. It refers to the total frequency of new and old cases of the disease recorded at a given time (point prevalence) or over a period (period prevalence).
  • Incidence rate. Rather, it refers to the speed at which the disease spreads, that is, the rate of contagion or at least the rate of new infections recorded during a given period.

In both cases, the calculation of the morbidity rate of a disease is always accompanied by information about the period studied and the geographical region affected.

Morbidity and mortality

If the morbidity rate refers to the rate at which a disease spreads in a given period of time and in a specific area, The death rate, on the other hand, refers to the number of deaths that occur in a given area and period.

Said mortality can refer either to all deaths, whatever their cause (general mortality rate), or to deaths due to a specific cause (particular mortality rate).

Thus, in epidemiology, it is common to study a disease both from its morbidity rate (number of registered cases) and mortality (number of deaths caused by it), to get an idea, from statistics, of how lethal the disease is and how easily it spreads.

More on: Mortality


  • “Morbidity” on Wikipedia.
  • “Morbidity” in the Language Dictionary of the Royal Spanish Academy.
  • “Mortality and morbidity” in Fundéu.
  • “Morbidity” in Thanatopedia Áltima.
  • “Health Indicators” in the Directorate of Health Statistics and Information of the Government of Argentina.