by Kimberly Allen RN
Most people think of epidemic and pandemic as being the same, however, they are not. though both terms do refer to an infectious disease that spreads rapidly the two are distinctly different.
Every year experts estimate how many cases of a particular illness, like the flu, are expected to occur in a particular population in a particular area based on previous years. This is called the incidence rate. An epidemic occurs when a particular illness develops and more people than the experts had predicted in the area where the illness occurs become infected. A pandemic usually involves not only even more people becoming infected but also over a much larger area. Pandemics tend to cover whole countries and even worldwide infections. For example, say several people develop the flu in a particular county, then more people across the state develop the same flu and the “incidence rate”, meaning the number of people that are infected, is much higher than the experts predicted. At this stage it is an epidemic. Now, take that same flu and multiply the number of people infected and then increase the area where people are infected from a state to the whole country. That’s a pandemic. Also, it is considered to be a pandemic if there are significantly more people infected in a more localized area like a state for an epidemic.
Pandemics are most often caused by a new virus or a subtype of a previous virus that has already infected people. Pandemics as a rule usually result in much higher death rates than epidemics. They are also more costly in medical care and loss of work, loss of school days and other economic issues than epidemics.
A pandemic usually develops when the influenza A virus suddenly changes. This change is called an antigenic shift. Proteins that are on the surface of a virus known as HA and/or NA proteins are suddenly in new combinations. This change makes the new subtype of influenza A. Then the most important thing this new subtype needs is the ability to spread rapidly from person to person. Then after thee virus subtype has created a pandemic it sticks around for several years and causes some seasonal flu epidemics.
There have been numerous pandemics through out history. HIV/AIDS is still considered to be pandemic and it started in the 1980’s. There are several organizations worldwide that monitor the movements and the behavior of the viruses. Both epidemics and pandemics can be serious depending on how virulent and resistant the virus is. The World Health Organization has developed a 6 stage program to measure the severity of pandemics ranging from no viruses circulating or reports of infection to sustained community infections in multiple countries. The World Health Organization added periods that occur after the 6th stage. The first is called the lost peak period, meaning the number of cases has fallen below peak levels and the post pandemic period which means the number of cases are the same as you would expect to see for the seasonal flu.
Because our world is so mobile today the potential for pandemic viruses to spread is much greater. The importance of getting an annual flu vaccine can’t be emphasized enough. Use hand sanitizer and practice good hand washing can also help you to avoid being a statistic this flu season.