What is immunity debt and what causes it?

Immunity debt: what it is, meaning, causes and possible remedies for the difficulty in defending oneself from certain diseases.

When the level of infections within the population, regardless of the type of virus, suddenly rises, it is easy to come across expressions such as "immunity debt". In its simplest form, this debt is the lack of immunity within a population. This can happen due to lack of exposure to a particular pathogen or due to lack of vaccination . The term was first used by epidemiologists to describe the phenomenon of a population "forgetting" how to fight a certain type of disease due to little or no exposure for long periods of time. When a population has "forgotten" how to fight a certain type of disease, over time it can become increasingly susceptible to epidemics.

Immunity Debt: Meaning, Definition and Causes

By definition, therefore, immunity debt is nothing more than the incapacity of a population to defend itself against the attacks of a virus due to lack of vaccination or "unused" immune defences. The longer the immunity debt goes unaddressed, the more difficult it is to protect the population from an outbreak. What makes this problem particularly serious is in the current global context: some parts of the world have been more exposed to certain diseases and have developed more immunity than other parts. As a result, some parts of the world that have had less exposure may be more vulnerable to outbreaks.

When a large portion of a population is vaccinated, diseases cannot spread as quickly or as easily. Unfortunately, some populations are unable to achieve herd immunity due to lack of access to vaccines. This is especially true for those in developing countries, where vaccine availability may be limited or non-existent.

This lack of access to vaccination leads to a decrease in the overall vaccination rate of the population and, consequently, an increase in the number of people at risk of contracting the disease. This is the debt of immunity and has caused a number of preventable epidemics over the past century, such as those of polio, measles, smallpox or even Coronavirus. In the case of the latest pandemic, among other things, the fact that isolation and lockdowns have made our immune defenses less accustomed to dealing with other types of viruses, such as the flu, also triggered a worsening of the debt. Hence the new peaks of infections in recent times.

How to deal with the lack of immunity

The pandemic has highlighted the importance of ensuring access to safe and effective vaccinations for all , regardless of geography or economic status. It is important to note that immunity debt does not go away overnight, but must be addressed over time. We need to focus on providing equitable access to healthcare and vaccination in all parts of the world so those countries can be better prepared in the event of an outbreak. This will help create a more complete and robust immune system so that we can better protect ourselves in the event of a new pandemic or another outbreak.

Immunity debt is a serious problem and needs to be addressed properly if we are to protect our population from future outbreaks. While it can be difficult to reduce exposure to certain diseases, making sure everyone has safe and effective vaccines available is essential to addressing this problem. We must recognize that affordable immunizations are one of the most powerful tools we have for fighting epidemics and protecting our populations.