Dengue vaccine: answer your questions – 02/07/2024 – Balance and Health

Amid yet another state of alert against dengue in the country, the Minister of Health, Nísia Trindade, highlights a mitigating factor: for the first time, Brazil will have the help of a vaccine to combat the disease.

Qdenga, manufactured by the pharmaceutical company Takeda, was incorporated into the SUS (Unified Health System) and should begin to be applied in February. It is now available in private laboratories at an average price of R$450 per dose.

Approval for the vaccine was received by Anvisa (National Health Surveillance Agency) in March 2023 for people aged 4 to 60 years. It is applied subcutaneously, in two doses, three months apart.

The 757,000 doses delivered by the manufacturing laboratory undergo a release process at the Ministry of Health, as occurs with imported medicines and vaccines that arrive in Brazil. The distribution schedule and quantity of doses for each region will be announced soon, says the ministry.

See everything we know about the vaccine and how to get it.

Who can receive the vaccine

In private laboratories, people aged 4 to 60 can receive the vaccine. To do this, they can take a medical recommendation or consult with professionals from the establishments themselves.

The price varies between R$400 and R$490 per dose in laboratories in São Paulo. In some, however, such as Fleury, stock is limited to customers who requested the second dose and in some units there is no longer any vaccine available, due to the high demand for immunization and the restriction of the vaccine manufacturer’s supply to the private sector.

Under SUS, however, the initial audience will be children and adolescents aged 10 to 14. This age group, according to the Ministry of Health, concentrates the highest number of hospitalizations due to dengue, after elderly people — a group for which the vaccine has not been released by Anvisa.

The ministry follows the recommendation of the WHO (World Health Organization) advisory group (Sage), which advised the introduction of the vaccine for people aged 6 to 16 years. “Within this age group, the vaccine should be introduced approximately 1-2 years before the peak incidence of dengue-related hospitalizations.”

Furthermore, the vaccine will only be applied in 521 municipalities in regions that meet the following criteria: have at least one municipality with more than 100 thousand inhabitants; high dengue transmission recorded in 2023 and 2024; greater predominance of dengue virus serotype 2 (DENV-2).

The Health department explains that the limitation was made due to the laboratory’s low production capacity.

Who cannot receive the vaccine

According to the drug leaflet, Qdenga should not be applied to pregnant women, breastfeeding women, people allergic to any of the vaccine components and those with immune system problems, such as HIV, genetic issues or who are undergoing treatment that affects the body’s defenses.

How effective is it and against which types of dengue does the vaccine protect?

In tests conducted in eight countries in Asia and Latin America (Brazil, Colombia, Dominican Republic, Nicaragua, Panama, Philippines, Sri Lanka and Thailand), the vaccine was 80% effective against confirmed dengue cases 12 months after the second dose, and reduced hospitalizations by 90.4% in the 18 months after the second dose.

Regarding efficacy by serotype, the analysis showed variable protection for each one, being 69.8% against serotype 1 and 95.1% for type 2, demonstrating good protection for the latter.

On the other hand, protection for serotype 3 was below the 50% efficacy limit (48.9%, with a range of 27.2%-64.1%) and, for serotype 4, it was inconclusive.

This last point worries experts, especially given the possibility of an epidemic of serotypes 3 and 4 in the country this year.

What are the possible associated risks?

Like any drug, the vaccine has expected side effects, such as pain or redness at the injection site, headaches and muscle aches, general malaise and weakness. Around 10% of those vaccinated may have a fever. Side effects are generally mild to moderate and may disappear within a few days.

An effect that may arise when applying the vaccine and worries scientists is the occurrence of a reaction called ADE (antibody-dependent increase). This occurs because the vaccine induces the production of antibodies linked to different serotypes, but it is not the same for each of them.

Thus, at the time of an infection with one of the types of the virus, instead of fighting it, antibodies can help the virus infect cells, causing a condition similar to that of dengue hemorrhagic fever – which can occur when contracting the disease for the second time. turn.

As shown by SheetTakeda states that after a study of more than four years of follow-up, the vaccine did not present any safety risk or worsening of the disease associated with vaccination, regardless of previous exposure to the virus.