Vaccination against Dengue in Argentina: Guidelines, Safety, and Efficacy

2024-04-10 15:45:22
Vaccination once morest dengue must be carried out with medical authorization in Argentina (Ministry of Public Health of Misiones)

Argentina remains immersed in the largest dengue outbreak in history, with 161 deaths and 232,996 cases registered, according to what was reported by the Ministry of Health in the last National Epidemiological Bulletin (BEN).

Currently, 19 jurisdictions in the 5 regions of the country have indigenous circulation of dengue, including all jurisdictions in the NOA, NEA, Cuyo and Central regions, in addition to the province of La Pampa in the Southern region.

And in the midst of this unprecedented epidemic, there are several measures to prevent the disease transmitted by the Aedes aegypti mosquito. One of the most recent is the dengue vaccine.

The tetravalent vaccine once morest dengue from the Japanese laboratory Takeda (TAK-003), known as Qdenga, was approved a year ago in Argentina by the National Administration of Medicines, Food and Medical Technology (ANMAT). And it had already received the green light from the European Medicines Agency (EMA) and the regulatory bodies of Indonesia, the United Kingdom, Iceland, Norway and Brazil, among other countries fighting this disease.

There are still questions regarding the effectiveness and safety of the mass application of this vaccine to the entire population. So far, the World Health Organization (WHO), the Pan American Health Organization (PAHO) and the Strategic Advisory Group of Experts (SAGE) of the international organization have recommended the use of the TAK vaccine. -003 for children aged 6 to 16 years who live in environments with a high burden of dengue disease and high intensity of transmission. This means a focused and segmented vaccination.

This is in part because the safety and efficacy endorsement of the TAK-003 vaccine was obtained through an extensive program of 19 clinical studies – which included the TIDES study, in which more than 20 thousand volunteers participated over 5 years – was carried out on the population of children from countries considered endemic, in the age range of 4 to 16 years. However, due to other “immunobridge” studies presented, it was concluded that it can be used in adults up to 60 years of age.

The new vaccine was approved by ANMAT a year ago in Argentina (Illustrative image Infobae)

The infectious disease doctor Pablo Bonvehí, head of Infectology at the CEMIC University Hospital, member of the Scientific Department of the Vacunar Foundation and member of the Vaccine Committee of the Argentine Society of Infectology (SADI), considered in dialogue with Infobae that “the vaccine is approved as of of 4 years without age limit (as in Europe and the United Kingdom), it is contraindicated in immunosuppressed, pregnant and breastfeeding women.”

“Any person who wants to reduce the risk of the disease and especially the risk of hospitalization, who meets the previous parameters and can access the vaccine and resides in areas where there are cases of dengue, can be vaccinated,” Bonvehí concluded.

Regarding the age group evaluated in the clinical trials, the infectologist specified: “The efficacy studies were not done in older adults because these studies require adults of those ages with and without previous infection and it is practically impossible to find them in endemic areas. , where the studies are done, people in these age groups who have not been infected in the past,” said the immunologist expert.

“In any case, it would be interesting to have immune response and safety data in people over 60 years of age. On the other hand, the risk of mortality is higher in adults aged 50 and 60 years and older. In Argentina, some data indicate that approximately 20% of vaccinated people are over 60 years old,” the expert concluded.

The infectious disease doctor Juan Carlos Cisneros (MN 62530) is deputy director of the Muñiz Hospital of the City of Buenos Aires, a reference center specialized in infectious diseases, and in response to Infobae’s consultation on whether the dengue vaccine is recommended for people over 60 years of age. , said that the decision on inoculation is linked to the clinical study that evaluated the vaccine.

“The study in which the vaccine was validated was carried out with people aged 4 to 60 years in the study and older groups were not included. But it is also true that the vaccine has been applied in other places and in those countries where older people have received it, no problems have arisen,” Cisneros said.

“The fact that this age group has not been included in the clinical trial implies that data on the duration of coverage with the vaccine in older people is still lacking, and one may suspect that it is shorter. Without a doubt, phase 4 studies will provide more certainty on the subject,” added the infectious disease specialist.

Takeda is the Japanese laboratory that developed the dengue vaccine, now recommended by the WHO

In recent statements to Infobae, Dr. Eduardo López, head of the Department of Medicine at the Ricardo Gutiérrez Children’s Hospital and director of the Career of Specialists in Pediatric Infectology at the Faculty of Medicine (UBA), said: “In Argentina the vaccine is approved from 4 to 100 years. Other countries have approved it from 4 to 65 years, others from 4 to 64 years, because the Takeda laboratory has carried out studies up to 64 years.

“Personally, I believe that if an older adult who is not within the risk groups, consulting their doctor in advance, can be vaccinated. Priority groups such as diabetes, morbid obesity and others, have to be among the groups to be vaccinated. Now, you have to get vaccinated in areas that really have a high incidence of dengue. That is why the analysis in large cities has to be done with caution, but also taking these groups into account,” the expert said.

Therefore, until information is obtained on the effectiveness and safety of the vaccine in people over 60 years of age, the recommendation is to consult with each patient’s primary care physician to define the individual vaccination decision.

Regarding a public health strategy to evaluate whether older adults should be included in a vaccination campaign, international and national health organizations must evaluate more scientific evidence that might be collected in the coming months, with Phase IV studies, from the application of the vaccine in the “real world”.

“The strategy must be analyzed with a multidisciplinary group based on the data. In Argentina, there are two provinces, Misiones and Salta, that are vaccinating with a protocol that is still not entirely clear,” López said.

New phase 4 studies of the vaccine will provide more information this year (Getty Images)

And he added: “Brazil, for example, is vaccinating early childhood children and adolescents, with which one sees that the ideal strategy has to be analyzed country by country and area by area. I believe that the National Ministry of Health should evaluate the strategy so that vaccinations can begin in May or June.”

Regarding vaccination once morest dengue, the head of the Health Ministry of the City of Buenos Aires, Fernán Quirós, stated a few days ago: “We know that it is a safe and effective vaccine for people between 4 and 60 years old. “What we are discussing is how to apply the recommendations of the majority of experts and the Pan American Health Organization (PAHO).”

“It is a vaccine that should initially be used with priority in a focused and segmented manner, where there is a very intensive circulation of the virus, that is, the rate of illness is very high as has been seen this year in the northeast and northwest of Argentina. And segment the age groups that get sick the most, as Brazil did for boys and girls from 10 to 14 years old, or as northern Argentina did for young people between 20 and 40 years old because it is the group that has the disease the most,” he described. Quiros.

The studies of the new vaccine once morest dengue were carried out in people up to 60 years old

Quirós anticipated that they hope “by May or June, to have a scientific evaluation of how (vaccination) evolved in the places where it was focused and segmented, and what social impact it had. Once we have the scientific information on those over 60 years of age and what was the impact on the effectiveness of the vaccine care in the effective field, that is, in Brazil, Paraguay and in northern Argentina, for the winter months we will have a very clear position,” concluded Quirós.

On March 7, the voices of experts belonging to the National Immunization Commission (CoNaIn) were added to the analysis of vaccination in an extraordinary meeting within the framework of the outbreak that is occurring throughout the country.

In the summary of the meeting, which is publicly accessible, they recommended beginning to outline a vaccination strategy, while clarifying the reasons why it should be developed selectively and for certain age and population groups.

The experts that make up this medical entity clarified some points to take into account. Although the safety and immunogenicity data have been verified for approval by the national regulatory body, according to what was expressed by the Dengue Vaccine Working Group belonging to CoNaIn, the following must be analyzed:

Vaccination once morest dengue is one of the tools to protect once morest the spread of the disease. (Illustrative image Infobae)

The absence of clinical efficacy data in people over 16 years of age. As has been done with other vaccines, efficacy in older people is interpreted based on immunobridging studies (previously presented to this commission). There is no proven clinical correlate of protection.

The vaccine presents immunogenicity data for the four serotypes. Regarding efficacy, there is evidence that in seropositive people the vaccine prevents infection once morest the four (4) serotypes and in seronegative people it did not show efficacy to prevent symptomatic disease caused by the serotypes. DEN-3 and DEN-4 or hospitalizations for DEN-3. There were not enough cases in the pivotal study sample to demonstrate efficacy once morest DEN-4. No protection once morest DEN-3 and DEN-4 might be seen in seronegative people, neither at 12 nor at 54 months of follow-up following the second dose, in a population aged 4 to 16 years in endemic areas.

Safety in people over 60 years of age: there is no reliable data. The ANMAT analyzed data regarding safety in older adults, which will be provided to be considered in the evaluation that is being carried out. The vaccine in Argentina is approved without age limit, the EMA also approved it with this modality. Brazil, on the other hand, only approves it up to the age of 60. It is essential in the face of the dengue epidemic in our country and the use of the vaccine in private, to analyze safety and laboratory data, that is, the need to differentiate whether positive PCR tests in vaccinated people with compatible symptoms are due to natural infection by the dengue virus or post-vaccine viremia (as described in the vaccine package insert).

The Takeda Pharmaceutical logo at its headquarters in Tokyo, Japan. The laboratory is in maximum production of its vaccine for Latin America (REUTERS/Kim Kyung-Hoon)

As Infobae learned in dialogue with sources from the Takeda Laboratory, the main commitment of the National Government and jurisdictions throughout the country is to start working for the next spring-summer 2024/2025 season.

Infobae confirmed with sources from the vaccine manufacturer that if a decision is made to mass immunize a certain population for the next season, it is essential to take into account the times it takes to produce the doses to immunize those with 2 doses. selected populations.

It is estimated that this process involves a time of no less than 6 or 7 months, which is why specialists insist that strategies for the next spring-summer season should already be analyzed.

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