00:00Herpes simplex type 2 infections have caused disease in humans for millennia.
00:06The viruses enter the human body through the skin or the lining of the mouth or the vagina.
00:12Once they enter the cells, they make their way into nerve endings
00:16and travel to the cell bodies of the nerves that transmit pain and touch.
00:23Herpes simplex type 2 makes its way to the area of the nerves
00:28that transmit pain and touch signals, known as the dorsal root ganglia in the spinal cord.
00:35A notherpes virus, the type 1 virus, tends to take up residence in a similar region
00:43in the nerves that transmit pain and touch in the facial region, known as the trigeminal nerve.
00:52Herpes viruses remain hidden in infected persons
00:55for the lifespan of the individual.
00:59Stressful conditions such as heat, trauma, fever, ultraviolet light
01:05can reactivate the sleeping virus,
01:09at which time it travels back down the nerve to the skin or mucosa,
01:15causing new eruptions on the surface.
01:18Occasionally, especially in persons with weak immune systems,
01:22the virus can cause serious infections, such as meningitis or encephalitis or widespread disease.
01:33Herpes type 2 infections in newborns are fatal in 60% of cases if left untreated,
01:42and herpes sores are a major risk factor for the transmission of HIV.
01:48These characteristics of the virus cause significant sickness and, in some cases,
01:56even death in individuals with weak immune systems or in newborns.
02:03Given the seriousness of herpes infections,
02:06the development of a vaccine would have a major impact on the role herpes plays in human disease.
02:15But, finding a vaccine for the herpes simplex virus has not been a walk in the park.
02:24Whereas we've been able to develop a preventive vaccine for the shingles or herpes zoster virus,
02:31multiple trials of finding a suitable vaccine to prevent herpes simplex type 2 have failed.
02:39These failures have resulted from the various complexities of the virus.
02:45The virus carries the genetic code for an array of proteins that help it to evade the immune system.
02:53Some of these make the virus invisible to the immune system during its latency phase.
03:01Other proteins inhibit interferon, a major substance the body produces to eliminate viruses that enter the body.
03:12Another protein inhibits the complement system, which is also involved in fighting viruses that enter the body.
03:19Yet, other proteins encoded by the virus prevent the presentation of viral material to the immune system for recognition,
03:30thereby rendering the virus unrecognizable by the immune system.
03:37Given that vaccines work through the immune system,
03:42any vaccines we develop must therefore overcome these obstacles.
03:47We can see by the frequent recurrence of herpes lesions that even our own immune system is incapable of completely suppressing
03:57the reactivation of the herpes simplex type 2 virus.
04:03The vaccines we develop to treat herpes infections must therefore produce an immune response in humans
04:12that is more powerful than the natural immunity the virus itself triggers when it enters our bodies.
04:22Scientists are actively seeking to overcome these difficulties by developing vaccines
04:30that target many of the proteins that help the herpes virus evade the immune system.
04:38An effective vaccine should prevent viral shedding in people without active sores
04:46to reduce the risk of unknowingly transmitting the virus through shedding of the virus when there are no sores.
04:56Despite these formidable challenges,
04:59current vaccine research offers hope for a future breakthrough.
05:04The fact that we already have a preventive vaccine for another herpes virus,
05:11that is, the shingles virus,
05:13is evidence that a vaccine to prevent herpes simplex type 2 is doable.
05:20Now, while these challenges remain,
05:23vaccine research continues to offer hope for future breakthroughs.
05:28The question remains whether these vaccines will offer long-term suppression of symptoms
05:36and transmission for a viral infection that has plagued humanity for thousands of years.
05:46I hope you enjoyed this video.
05:48If you did, like and share the video with your friends and family.
05:52You can support this channel by subscribing.
05:56Until the next video,
05:58stay healthy and stay safe.
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