New dengue vaccine: understand how it works

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In 2023, a National Health Surveillance Agency (Anvisa) approved a new dengue vaccine in Brazil – this is the Qdengfrom the pharmaceutical company Takeda, which promotes protection against the four serotypes of the virus.

data of Epidemiological Bulletin of the Ministry of Health, indicate that more than a thousand people died from dengue in 2022 (the highest rate since 2015, when 986 people died from dengue). In addition, in the last year, there were also nearly 1.5 million probable cases of the disease.

What is Dengue?

Dengue It is a viral infection transmitted by the bite of a female mosquito. Temples of the Egyptians and represents a major public health problem not only in Brazil, but in several countries in Latin America. There are four different serotypes of the virus, and recovery from infection with one serotype provides lifetime immunity against that serotype alone.

Therefore, subsequent exposure to any of the other serotypes may be associated with an increased risk of serious illness, hence the importance of keeping vaccination up to date.

One of the ways to avoid transmission is to control the mosquito vector — avoiding standing water in containers, tires, vases. That is, vaccination ends up being one more tool in the quest to control the disease, which continues to cause an epidemic in Brazil. It’s years of study in search of an immunizer that is effective.

How does the new Dengue vaccine work?

A Qdeng is a vaccine that is based on serotype 2 of the attenuated dengue virus (when the virus remains alive, but weakened, without the capacity to cause the disease, as in vaccines against mumps, yellow fever, oral poliomyelitis and measles).

According to Takeda, the basis of serotype 2 of the virus provides the genetic “skeleton” for the other serotypes of the virus, so the vaccine can protect against any of them. Recently, the vaccine was approved to be used in any person from 4 to 60 years old and must be administered subcutaneously, in two doses, with an interval of three months between them.

According to the pharmaceutical, the effectiveness was demonstrated from the first dose, being expanded with the booster. But, as with other vaccines, research has indicated a decrease in effectiveness in the second year of follow-up after vaccination (24 months) and, therefore, the pharmaceutical company is evaluating the need for a booster dose after 4.5 years.

“This evaluation is in progress, but we cannot yet conclude whether a booster will be necessary, since the vaccine continued to demonstrate a significant reduction in hospitalizations (84%) and general cases of dengue (61.2%), even after follow-up 4.5 years, with the recommended primary scheme. In any case, Takeda will continue to evaluate the potential need for a booster dose”, informs the laboratory in a note.

How the new vaccine was developed

To develop the vaccine, 19 phase 1, 2 and 3 studies were carried out involving more than 28,000 people (children and adults) in endemic and non-endemic areas. All were followed up for four and a half years. The results indicate that the vaccine achieved its primary efficacy objective, which
varied by dengue virus serotype.

But, according to the manufacturer, the analyzes show that over the course of four and a half years, the vaccine prevented 84% of hospitalization cases of dengue and 61% of cases of symptomatic dengue in the total study population.

The main advantage of this vaccine in relation to the existing vaccine is that it can be applied to anyone between 4 and 60 years old without the need for a pre-vaccination test to find out if the person has previously been contaminated by the virus.

“The approval of this vaccine is very important because it will protect against a very prevalent and frequent disease in our midst. It is a very safe and effective vaccine for this age group that has been approved. In addition, it does not have the inconvenience that the other vaccine has, which could bring an increased risk to those who had never been infected before,” he said. Alfred Elias Gilliopediatric infectologist and coordinator of the Immunization Clinic at Hospital Israelita Albert Einstein.


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