Vaccines are one of the greatest scientific innovations of all time. In the last century, they have given us a glimpse of the end of polio and helped us eradicate smallpox. Thanks to vaccines, billions of people are living healthy and protected from vaccine-preventable diseases like measles and whooping cough. For this reason, each year the World Health Organization promotes World Immunization Week, in 2022 it is commemorated from April 25 to 30.
In the last 30 years alone, infant mortality has decreased by more than 50%, thanks in large part to vaccines. But adults have also benefited, vaccines now help protect against more than 20 diseases, from pneumonia to cervical cancer and Ebola.
Within the framework of this reminder, Mexico has just approved a recombinant herpes zoster vaccine produced by GSK laboratories, to talk about it El Economista was able to talk with Dr. Gloria Huerta, infectologist, pediatrician, Master of Medical Sciences and Medical Manager of Vaccines in that company.
She explains that shingles is a consequence of having had chickenpox. “All of us who suffered from it are going to keep that varicella zoster virus and it stays in our body for the rest of our lives in sensory areas.” As we age, so does the immune system (immunosenescence), this means that in certain conditions, stress, depression, or diseases that are added to our body, this virus reappears.
Its characteristic is that it is similar to chickenpox, but localized in sensitive areas (mainly trunk, chest, but also on the face, buttocks, etc.). “They are vesicles with water, which are very painful at the acute moment and can cause itching, there are even times when pain medications are not effective, the damage can last for months or years (postherpetic neuralgia) and can impact quality of life for the sensations it leaves”.
Even with a reactivation of the nerves next to the eye, for example, you could lose your sight; around the ear, hearing, depends on multiple factors so that the risk is higher or lower.
In Mexico, the incidence of herpes zoster is estimated at around 220,000 cases per year: the estimated risk of developing this disease throughout life is 10 to 20%, although in the case of adults over 75 years of age it exceeds 10 cases per thousand people per year, while in the case of people living with HIV the incidence reaches 29.4 cases per thousand inhabitants per year.
The also head of Hospital Epidemiology of the Trinidad Hospital, assures that being an infectious disease, we can have a vaccine, we have it (chickenpox) and it is applied to the first year of life with a two-dose scheme, this prevents it from appearing in 90% the disease, but if we already had chickenpox, now we have to prevent herpes zoster from appearing.
Although there was previously a vaccine against this condition, it was with technology similar to that of chickenpox, that is, live attenuated viruses are used, but the specialist deepens: “This carries a risk as we age, because our immunity decreases and with live viruses , immunity can be so low or compromised that applying a vaccine with these characteristics can carry the risk of producing the disease, which is why there are some contraindications for certain groups”.
With this scenario, it was that the researchers decided to look for new technology options. It was decided on a recombinant vaccine, “it is one of the most frequent, the first one we had was against hepatitis B, HPV and this is a third option”, this means that the genetic material of the virus that produces the protein is chosen, which generates antibodies and our defenses “that bit of genetic material (DNA), I take it to another cell, so that it produces this protein, I exclusively purify that protein and thus I do not have the infective capacity, it is not a live virus, only the protein produced by recombining DNA, in this case, has an adjuvant, which potentiates the immunological effect”.
You already have the registration, what’s next?
On March 8, this vaccine received its registration by Cofepris, from there a series of technical and regulatory processes begin to bring the product with quality. With this ahead, it is expected that in the first months of next year this vaccine will be in circulation in the country. “Initially it would be reaching the private sector and working to include it in the public health sector as quickly as possible.”
At this time, the vaccine has a broad indication in Mexico, because it has already been on the international market since 2017, that is, there is already previous experience. At first it was studied for people over 50 years of age or immunocompromised. These are the clearest groups of patients, however if we consider that in Mexico today 95% of the adult population suffer from chickenpox, the risk is clear. The possibility of suffering from it after the age of 50 is 1 in 3 and after 80 it is 1 in two. The interesting thing is that it is a preventable disease through vaccination.
Huerta concludes: “Because of everything we have experienced with Covid-19, we have had great lessons learned and one of them is that vaccines change the course of humanity, that they save lives. Since they have been formed, they have changed childhoods; before them, only four out of ten children reached the age of five and we understood that they must be vaccinated, now with the pandemic we are understanding that it can also change the lives of adults and older adults, it is about prevention awareness ”.
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