Although they are sometimes used interchangeably, an epidemic and a pandemic differ in their severity, the people they affect, and their extent.
An event of these dimensions has occurred few times in the history of mankind. And the turning point occurred when the WHO classified the Covid-19 crisis as a “pandemic”, ceasing to be considered an epidemic.
Epidemic and pandemic are not synonyms. An epidemic is something totally common that, generally, does not usually represent any health alarm. The problem is that if the conditions are met, it can become a pandemic, an alarming situation in which the spread of the disease is uncontrollable and reaches almost the entire world.
Therefore, in today’s article we will analyze the main differences between epidemic and pandemic , taking into account that pandemics are a very rare event. In fact, that of Covid-19 is, together with that of HIV , one of the only ones that we have suffered in recent history.
How do we differentiate an epidemic from a pandemic?
The border between what is an epidemic and what is a pandemic is usually very subtle, since they are simply labels that we put on situations in which a contagious pathogen begins to spread between people and increases the incidence of a disease to a greater or lesser extent. specific infection.
In any case, there are mainly three factors that help determine whether a situation with these characteristics is an epidemic or a pandemic: the extent of the affected region, severity and the microorganism responsible for the disease.
1. Extent of the affected region
The main difference between both events is the extent of the area affected by the spread of the pathogen responsible for the disease. Broadly speaking, the epidemic is usually reduced to a specific region, being able to control the progress of the disease to a greater or lesser extent. In a pandemic, practically every country in the world is affected , as there is no way to control its spread.
1.1. Epidemic
An epidemic is a localized outbreak of an infectious disease . They are much more frequent than pandemics since they are confined to a specific place at a specific time. And although they can affect entire cities or even a country, they do not usually cross borders. Its control and eradication is easier precisely for this reason.
In fact, epidemics are so common that every year we suffer at least one: the flu. It is the clearest example, because depending on the time of year, each country has a flu epidemic that, although it causes a very high increase in the incidence of this disease, is located exclusively in this nation.
In any case, epidemics are more common in underdeveloped countries, since the lack of resources, poverty, poor hygienic conditions, lack of medicines or water sanitation systems, etc., make the spread of diseases much more easier than in more developed countries.
1.2. Pandemic
A pandemic is a totally different situation. They always come from an epidemic whose progress cannot be controlled, causing the disease to cross borders and begin to spread almost everywhere in the world. It is a much more alarming situation for this reason. It is not located in a city or country. All (or almost all) the countries of the world see the incidence of the infectious disease in question increased.
A clear example of this is the Covid-19 or HIV pandemic, perhaps the only two examples of a pandemic since the Spanish flu of 1918. In both, the causative pathogen managed to spread throughout the world. In the case of HIV, since it began to spread in the 1980s, it has killed more than 30 million people. It is a pandemic that has been with us for about 40 years.
2. Gravity
Seeing the above, it is evident that the severity of an epidemic and a pandemic are not at all similar . An epidemic is usually a relatively mild situation. A pandemic is a global public health alarm, so it is very serious.
2.1. Epidemic
An epidemic does not tend to be serious for a simple reason: they are almost always caused by pathogens with which we have been living for a long time. This makes many of us immune and does not infect us, which explains why its control is easier and it does not spread worldwide.
In addition, the fact that we have been in contact with the pathogens that typically cause epidemics (such as the flu) makes our relationship even closer. This means that the virus or bacteria responsible has become less and less aggressive.
And it is that we must remember that no pathogen wants to kill us. When they infect us, we are their “house”. What they want is for us to be as healthy as possible, because that way they can develop and replicate more efficiently.
A very lethal pathogen is an evolutionary failure, because if we die, so do they . Therefore, as time goes by, they become less aggressive, since it is the most profitable for them. And in epidemics is what usually happens. A flu, although it is true that it can be fatal for the population at risk, is not serious at all for other people. We have been living with the flu virus for a long time, so it has found the balance between obtaining benefits but not causing us too much damage.
2.2. Pandemic
A pandemic is a very serious situation . Not only because their spread is worldwide, but because they tend to be more dangerous diseases. This means that health systems can become saturated, that there are effects on the world economy and that many people die.
It is only necessary to observe what, as this article is being written, is happening with Covid-19. And it is that although an epidemic is overcome without major complications (if it occurs in developed countries), a pandemic affects all areas of society, in addition to bringing together all the ingredients to cause fear.
It is a serious situation since many people around the world are infected by a disease that until then was unknown, there are usually no treatments or vaccines, it is usually linked to higher mortality than epidemics, there are doubts about the mode of contagion , there is a lack of herd immunity, the economy is reeling… Pandemics are very rare but when they do break out, the consequences are felt long after they are over.
3. Causative microorganism
All epidemics and pandemics are caused by microorganisms, be they bacteria or viruses, easily transmitted between people. These pathogens, once inside the body, harm us and make us sick. But not everything is the same.
Epidemics are usually caused by known pathogenic microorganisms . A pandemic, on the other hand, is always caused by a “new” germ.
3.1. Epidemic
As we have said, epidemics are usually caused by pathogens that have been circulating around the world for some time and are by no means unknown. They can be bacteria or viruses, but the positive point is that, having been with us for a long time, we are more prepared to fight them.
And it is that many people are immune to these bacteria and viruses , because they have come into contact with them in the past and when there is a new epidemic, their body is resistant to their attack. There is collective immunity, something that does not happen with the pandemic.
Also, by being around for a while, scientists have had time to research and discover treatments. Antibiotics are capable of curbing epidemics caused by bacteria. And, in fact, compliance with hygienic measures at a social level and access to these drugs has meant that there are practically no bacterial epidemics, at least in developed countries.
With viruses it is something different. And we still do not have drugs that can kill them. A viral disease must be overcome by the body itself, although there are therapies to stop the replication of the virus and control the symptoms. In any case, this lack of drugs to neutralize them makes them responsible for most epidemics.
Influenza viruses, the common cold, gastroenteritis… All these cause the majority of cases of outbreaks and epidemics today.
3.2. Pandemic
A pandemic is caused by a “new” pathogen , usually a virus. Bacteria do not usually have as high a transmission ease as viruses. This, together with the fact that current hygiene measures are effective in slowing its spread, means that only viruses (in principle) have the potential to cause a pandemic.
For there to be a pandemic, the virus must be unknown to our body, that is, it has never come into contact with humans. It must also have a spread among simple people, with airborne transmission being the most effective for the virus, as is the case with the coronavirus.
This means that it can be transmitted quickly and, as there is a lack of collective immunity, practically all of us are sensitive to the virus and it makes us sick. Because many conditions have to be met, pandemics are very rare events.
In any case, throughout history we have suffered devastating pandemics: smallpox, measles, the Black Death, the Spanish Flu of 1918, the Justinian Plague… Although we must remember that medicine has come a long way and that Living conditions are much better now, so it will be difficult for us to suffer catastrophes of these proportions again. Pandemics will continue to occur, but they will be overcome as long as efforts are made at all levels of society.
Bibliographic references
- Qiu, W., Rutherford, S., Mao, A., Chu, C. (2017) “The Pandemic and its Impact”. Health, Culture and Society.
- Independent Commission on Multilateralism (2017) “Global Pandemics and Global Public Health”. USA: International Peace Institute.
- Centers for Disease Control and Prevention. (2012) “Introduction to Epidemiology”. Principles of Epidemiology in Public Health Practice.
- World Health Organization. (2018) “Managing epidemics: key facts about major deadly diseases”. WHO.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.