Want to learn more about herpesviruses?
Herpesviruses are major pathogenic viruses that can give rise to severe diseases especially in children, immunocompromised individuals, and elderly, that have the ability to establish latent-recurrent infections, and that therefore remain a life-long threat”.
Want to learn more about the immune system?
The immune system is our fundamental defense mechanism. It has aided the evolution of our species, enabling us protection from pathogens such as bacteria, viruses and fungi. Without this complex system of immune cells and defense proteins, we would quickly succumb to lethal infections.
The immune system has an incredibly intricate job of identifying invading microbes and to distinguish self from non-self. This is a fine balance between the recognition of dangerous invaders such as E.coli bacteria or Influenza virus, and the identification of our own cells and proteins. For most humans, our immune system functions in a way that offers us protection from pathogens that might want to do us harm. However, the immune system can also be the very thing that causes harm if it malfunctions, resulting in autoimmune diseases like sclerosis and arthritis.
Even a fully functional immune system is also not always able to eliminate infections, as seen for instance for herpesvirus infections. This is because pathogens have evolved counter measures which enable them to subvert the immune system. This prevents our defense mechanism from identifying and attacking potentially disease-causing microorganisms. Given the enormous impact of the immune system on human health, there is a need to further understand this complex system. Research in immunology may lead to new vaccines and treatments against infections, inflammatory diseases, and cancer.
Challenges and opportunities
Despite available drugs against some herpesviruses there are still insufficient options for treatment and prevention of infections with these viruses. With the recent advance in the understanding of immune response to infections, there are new opportunities to use this knowledge.
Prevention of herpesvirus diseases in the elderly
Over the last half century, the increasing life expectancy worldwide has resulted in the growth of the population over 50 years old. Although this population will continue to increase in size, it may not age healthily. As a result of immunosenescence (the gradual decline in the ability of the immune system to fight infections), co-morbidity and general frailty, the elderly are more susceptible to infectious diseases. Moreover, these individuals are more prone to infections not only with emergent pathogens, but also with infections they have encountered previously.
Herpesviruses are prevalent among elderly populations. The five causing the most health concerns are: herpes simplex virus (HSV) type 1 and 2, Epstein–Barr virus (EBV), cytomegalovirus (CMV), and varicella zoster virus (VZV). These well adapted pathogens establish a latent lifelong infection, manipulate the host immune system in a variety of ways, and may reemerge after many decades at unpredictable times to cause severe complications. For example, herpes zoster (HZ or shingles) strikes millions of older adults annually worldwide and disables a substantial number of them via postherpetic neuralgia (PHN).
Vaccinating people aged 50 and older against herpesviruses may be one strategy to promote healthy aging. At present, only one vaccine is licensed for the prevention of herpesvirus infection, a live attenuated vaccine against VZV, which is approved by the FDA. The administration of passive immunization may also prevent, or at least attenuate, shingles in high-risk individuals. Currently, experimental vaccines for Epstein-Barr, HSV-1 and 2, CMV are in various stages of clinical trials.