How does the new vaccine work?
Qdenga is a vaccine based on serotype 2 of the attenuated dengue virus (when the virus remains alive, but weakened, without the ability to cause the disease, as happens in vaccines against mumps, yellow fever, oral polio and measles).
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According to Takeda, the basis of serotype 2 of the virus provides the genetic “skeleton” for the other serotypes of the virus, so the immunizer can protect against any of them.
Still according to the pharmaceutical company, the effectiveness was demonstrated from the first dose, being expanded with the reinforcement. Research has indicated a decrease in effectiveness in the second year of follow-up after vaccination (24 months) and, therefore, the need for a booster dose after 4,5 years is being studied.
“This evaluation is ongoing, but we cannot yet conclude whether the booster will be necessary, as the vaccine continued to demonstrate a significant reduction in hospitalizations (84%) and overall dengue cases (61,2%), even after monitoring 4,5 years, with the recommended primary scheme. In any case, Takeda will continue to evaluate the potential need for a booster dose,” the laboratory said in a note.
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Dengue is a viral infection transmitted by the bite of a female mosquito. Aedes aegypti. The disease is a public health issue not only in Brazil, but in several Latin American countries. There are four serotypes of the virus and recovery from infection with one type gives lifelong immunity against it only. Subsequent exposure to any of the other serotypes increases the risk of serious illness, hence the importance of a vaccine.
Dengue killed more than a thousand people in 2022 and reached almost 1,5 million probable cases last year, according to data from the Ministry of Health's Epidemiological Bulletin.
The fight against dengue still remains the control of the mosquito vector, with care and cleaning actions: avoiding stagnant water in containers, tires, vases. Vaccination ends up being another tool in the search to control the disease, which is still epidemic in Brazil.
Vaccine development period
19 phase 1, 2 and 3 studies were carried out involving more than 28 thousand people (children and adults) in endemic and non-endemic areas. All were followed for four and a half years. The results indicate that the vaccine achieved its primary efficacy objective, which varied by dengue virus serotype.
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But the coverage is not 100%: according to the manufacturer, analyzes show that over the four and a half year follow-up, the vaccine prevented 84% of cases of dengue hospitalization 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 it can be applied to anyone between 4 and 60 years old without the need to carry out a pre-vaccination test to find out if the person has previously been infected by the virus.
“It is a very safe and effective vaccine for this age group that has been approved. Furthermore, it does not have the inconvenience that the other vaccine has, which could bring an increased risk to those who have never been infected before”, stated Alfredo Elias Gilio, pediatric infectious disease specialist and coordinator of the Immunization Clinic at Hospital Israelita Albert Einstein.
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For now, Qdenga is not yet available in Brazil. The Medicines Market Regulation Chamber, an interministerial body, linked to Anvisa, still needs to define the price, and only then proceed with the import of the immunizer and sale to health clinics.
According to Anvisa, in the report released on March 02, the granting of registration allows the product to be sold in the country, as long as the approved conditions are maintained. It will be available in private clinics. There is no information on the public vaccination calendar.
Source: Einstein Agency
@curtonews Anvisa approved a new vaccine against dengue in Brazil. The vaccine can be applied to anyone between 4 and 60 years old. 💉 #CurtoNews ♬ original sound – Curto News
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