Medical Biotechnology | There is finally a way to avoid the excruciating pain of "spondylosis"

Statistics show that nearly 3 million adults in China suffer from "spinelitis" every year. Many people describe the pain of suffering from this disease as being like being electrocuted or cut by a knife, and even as unbearable as wanting to die.

Now, there is finally a way to prevent it in advance, and no longer be afraid of being entangled by "Dragon of the Waist"!

A really tough disease

"Herpes zoster" is also called "herpes zoster" or "herpes zoster". It is an acute herpetic skin disease caused by infection with varicella-zoster virus (VZV). Its formal name is herpes zoster.

The main clinical manifestation of herpes zoster is the growth of dense groups of small blisters on the local skin, which are distributed in a band-like manner along the peripheral nerves on one side, often accompanied by neuralgia and local lymph node swelling and pain.

The natural course of herpes zoster may only last 2 to 3 weeks, but one of its sequelae, post-herpetic neuralgia, is very stubborn. It is a burning, electric shock, or stabbing pain that may last for months or even years, seriously affecting the patient's normal work and life, and even causing serious complications such as blindness, hearing loss, pneumonia, encephalitis, and stroke. This shows how "difficult" this disease is.

Old age, cellular immune deficiency, genetic susceptibility, mechanical trauma, systemic diseases (such as diabetes, kidney disease, fever, hypertension, etc.), recent mental stress, fatigue, etc. are common causes of herpes zoster. Women are at a higher risk of developing herpes zoster than men. For people over 50 years old, VZV-specific cellular immune function will gradually decrease with age, and the incidence, hospitalization rate and mortality rate of herpes zoster will gradually increase.

It is reported that the incidence of herpes zoster in the general population is 3-5/1000 people/year worldwide, 3-10/1000 people/year in the Asia-Pacific region, and increases by 2.5%-5.0% year by year. The hospitalization rate of herpes zoster is 2-25/100,000 people/year, the mortality rate is 0.017-0.465/100,000 people/year, and the recurrence rate is 1%-6%.

The "latent" virus of love

When children are infected with VZV for the first time, they will develop chickenpox. After recovery, the virus remains dormant in the body. A small number of patients will develop shingles due to recurrence of the virus in adulthood, so VZV is called varicella-zoster virus.

VZV can be transmitted through droplets and/or contact, and primary infection mainly causes chickenpox. Residual VZV can retrograde along the sensory nerve axons, or through the fusion of infected T cells and neurons, transfer to the dorsal root ganglia of the spinal cord or cranial nerve ganglia and remain latent. When the body's resistance is reduced, VZV-specific cellular immunity decreases, the latent virus is activated, replicates in large quantities, transfers to the skin through the sensory nerve axons, penetrates the epidermis, and causes herpes zoster.

VZV belongs to the human herpesvirus alpha family and is named human herpesvirus type 3. VZV has no animal reservoir host, and humans are the only natural host. The skin is the main target organ of the VZV virus.

VZV virus particles are spherical, and the complete virus consists of a core, capsid, envelope, and capsule. The envelope surface contains gB, gC, gD, gE, gG, and gH glycoproteins, which are related to the virus's adsorption/penetration into cells (gB, gC, gD, and gE), controlling the virus's budding release from the cell nuclear membrane (gH), and inducing cell fusion (gB, gC, gD, and gH).

gE is the glycoprotein with the highest expression in VZV-infected cells. It is essential for VZV replication and cell-to-cell transmission, and is highly immunogenic. It is the main target of humoral and cellular immunity. Studies have shown that after the first infection with VZV, the body will produce anti-gE antibodies, and CD4+T cells will produce a specific response to gE. gE can effectively prevent the occurrence of herpes zoster and its complications by enhancing the body's immune response. Therefore, gE is widely used in the development of herpes zoster vaccines.

More powerful weapons

Vaccination is the most effective means of preventing and controlling infectious diseases. To deal with the difficult shingles, it is time to pick up the powerful "weapon" of vaccination!

There are two types of shingles vaccines: live attenuated vaccine and recombinant protein vaccine. The U.S. Food and Drug Administration (FDA) first approved the live attenuated shingles vaccine produced by Merck in 2006, but found that the protection rate of the vaccine decreased significantly with age. Therefore, the vaccine was not approved for marketing in my country.

On October 20, 2017, the FDA approved the marketing of the adjuvanted recombinant shingles vaccine. The vaccine is a subunit vaccine containing recombinant glycoprotein E (gE) and a novel adjuvant AS01B. The preparation method is to insert the VZV glycoprotein E (gE) gene into Chinese hamster ovary (CHO) cells through DNA recombination technology to express specific antigens, add the company's specific adjuvant AS01B after purification, and freeze-dry. Existing studies have shown that the vaccine can reduce the risk of herpes zoster by more than 90% in all age groups and is still effective 4 years after vaccination; for postherpetic neuralgia, the overall protective effect of the vaccine for people aged 70 and above is 88.8%.

On May 22, 2019, the National Medical Products Administration conditionally approved the import registration application for the recombinant herpes zoster vaccine. According to the instructions for the vaccine, all adults aged ≥50 years, regardless of whether they have received varicella vaccine or other herpes zoster vaccines before, and regardless of whether they have had chickenpox, can receive the herpes zoster vaccine as long as they have no allergic reaction to the active ingredients or excipients of the vaccine. Considering the possibility of recurrence of herpes zoster, it is recommended that patients with a history of herpes zoster continue to receive the vaccine.

At present, several domestic companies are also conducting research on shingles vaccines. The live attenuated vaccine has entered the clinical research stage, and research on recombinant vaccines is also being accelerated.

Author: Yaohuluwa Medical Biotechnology Science Popularization Group