WHO: Global Influenza pandemics pose serious risk to health

Kartik Nath, Staff Writer

The World Health Organization (WHO) defines a pandemic as the “worldwide spread of a new disease.” The influenza virus, one of the most prevalent and rapidly-evolving viruses, has the potential to cause a worldwide pandemic at any time. Since viruses mutate and their genetic composition changes, new strains can wreak havoc among people who have no immunity against the virus, because they have had no previous contact with it. Any day, a virus could randomly mutate, or experience a change in their internal structure, thus causing the virus to develop new properties not known to any human immune system. It is difficult to predict the behavior of the circulating viruses. That is why the WHO has declared the potential for a “global influenza pandemic” as a threat to global health, and is spreading awareness for the need for countries to recognize the potential consequences of an influenza outbreak. The question becomes: What will be done about it?

The biology of the influenza virus is vital to understanding how it infects and reproduces. The antigen is a structure on the surface of the virus that the human immune system can recognize and it immediately triggers a response to prevent the virus from penetrating the body. When any human is exposed to the influenza virus, their immune system makes structures called antibodies that are specific to the antigens on a particular virus, so that the body can remember the specific structure of that particular virus. The Center for Disease Control and Prevention (CDC) uses the term “antigenic properties” to describe the antibody or immune response triggered by the antigens on a particular virus.

According to the CDC, there are two types of flu, the seasonal and pandemic flu. Flu viruses are constantly evolving, and can change through an “antigenic drift” or an “antigenic shift” (CDC). An “antigenic drift” represents small mutations in the genes of the influenza viruses that occur randomly and produce viruses that are very similar to one another. The viruses share the same antigenic properties, so if the human immune system is exposed, it can instantly recognize the closely related virus, and respond appropriately. The “antigenic shift” is a major genetic change in the virus, resulting in new protein combinations in the viruses that are unknown to any immune system and can cause catastrophic damage. These pandemic viruses have different antigenic properties, and the human immune system cannot recognize the genetic combination of the virus, thereby having no protection. The CDC named the H1N1 virus in 2009 as an example of antigenic shift, which caused a pandemic infecting numerous people.

The World Health Organization devotes a lot of resources to raise awareness around the severity of various influenza viruses, and initiates the prevention of the pandemic through research analysis. The WHO has a system that tracks the spread of various strains of the influenza virus across the world, called the “Global Influenza and Response System (GISRS).” The virus strains contained in influenza vaccines have to continually be updated to combat the evolution of the influenza virus, including the circulating viruses infecting humans. The WHO hosts a meeting biannually in Geneva, Switzerland, with a group of influenza experts, to analyze the surveillance data generated by the GISRS and compose a plan for configuration of the influenza vaccines for the corresponding influenza season. The WHO experts use epidemiolocal data and clinical information to study and analyze the circulating viruses, at the public health and molecular level. The advisory group lay out a plan for updates in the vaccine based on their analysis and interpretation of the virus behavior, and their plans vary by regions of the world. Actions like these meetings are necessary to ensure that any country is prepared for any situation, or any type of virus, to manifest.