BRASÍLIA, Brazil (FOLHAPRESS) – Anvisa (National Health Surveillance Agency) has decided to increase the restriction on the dengue vaccine produced by Sanofi Pasteur, the only one approved to date and available in the country.
In practice, the agency will give a contraindication to the use of this vaccine in people who have never had contact with any of the four serotypes of the dengue virus.
The measure comes after studies by the company suggest that people who have never had the disease will develop more severe forms of dengue if they are infected with the Aedes aegypti mosquito.
The result is part of a monitoring study of Sanofi in patients who have received the vaccine in the clinical trial phase in other countries, who assess the efficacy and safety of the product.
In November of last year, the agency had already placed a warning in the package leaflet advising that seronegative people for dengue did not take this vaccine, known as Dengvaxia.
The claim then was that the measure was taken as a prudence until new assessments were made about the case.
Upon termination of these evaluations, Anvisa will contraindicate it for this group.
"In the previous leaflet it was a precautionary measure to check the patient's serology and today this precaution is a contraindication to the vaccine. [para quem nunca teve o vírus]"says the director of the agency's mandates and documents, Alessandra Bastos Soares.
She remembers that until November last year the vaccine was indicated for people aged 9 to 45 who live in endemic areas, regardless of whether or not they had the disease.
Now the vaccine is still indicated for this group, provided that there is confirmation that the person is HIV positive for dengue. "It is fundamental that the patient's serology is completed," says Soares, who recommends that health professionals ask for tests before giving advice on the application.
In another change, Anvisa also defines as "endemic area" all municipalities where more than 70% of the population is already infected by one of the four dengue types.
It is expected that the package leaflets will change within 30 days. In case of already distributed vaccines, it is the intention that at the end of this period a new document will be sent to the clinics.
In the same period, the company must also present a risk management plan, reporting the follow-up of already vaccinated patients, he reports.
Approved in 2015 by Anvisa, the vaccine produced by Sanofi was the first to get permission to be put on the market in the country.
Other companies, such as the Butantan Institute, are also developing vaccines against the disease – but these products are still in the testing phase.
Despite the approval, the Sanofi vaccine was already seen with the reservations of technicians from the Ministry of Health, for whom the product has a low effectiveness – about 66%. The situation postponed the discussion about the inclusion in the National Immunization Program.
Currently the vaccine is available in private clinics, for a cost of up to $ 135 per dose. Since August 2016, the vaccine has also been used in campaigns by the Parana government. At least 300,000 people, 30 provinces in the state, have already been vaccinated.
& # 39; POTENTIAL & # 39; RISK
Asked about the report, Sanofi medical director Sheila Homsani said the risk data is still provisional. Yet it says that the company must adhere to the decision of Anvisa.
"We are not sure if it would be risky, but because the data showed this possibility, we agree with the decision." If the person has previously had dengue, she will benefit from the vaccine. .
According to Anvisa, the risk would be five hospital admissions for every thousand patients who have never had dengue and have been vaccinated against the disease. On the other hand, cases of serious dengue fever (also known as dengue fever with signs of alarm, before the severe phase) would amount to two in a thousand.
For Homsani, the data has no & # 39; statistical relevance & # 39 ;. "We may need a larger study, but we understand that it is best not to vaccinate seronegatives."
President of the Brazilian Association of Dengue and Arbovirus, the infectiologist Artur Timerman disputes and says that the data are alert and require monitoring.
He also advises that patients who have taken the vaccine will strengthen precautionary measures against the mosquito.
"You have to point out to people who have taken the vaccine that they are at risk: at the first symptom, they need to seek medical attention, because early treatment can prevent evolution from becoming serious," he says.
Although Anvisa's decision is considered correct, Timerman says that the criterion for recommending the vaccine to people who are positive for dengue and lives in endemic areas creates a gap: the lack of seroepidemiological studies in the country.
"Today we do not know how many people have had dengue, and with zika there is confusion, because serologies sometimes come together." The person who had zika may appear with antibodies to dengue, "he says, for whom the ideal is the vaccine is only indicated if there is no doubt about the previous picture.
But what leads to an increased risk for someone who has never had contact with the virus?
According to Anvisa, the risk is likely because in this case the vaccine would be interpreted as the first infection by the body of the seronegative patient. In general, new dengue infections are more serious than the first.
The agency emphasizes that the vaccine for HIV-positive patients is still indicated and has an efficacy of 73%, thereby avoiding more serious cases leading to hospitalization, he reports.
Data from the government of Paraná and private clinics indicate that at least 350 thousand people have already received the dengue vaccine in the country.
Sanofi says he does not have this information. However, the company says that 1 million doses have been applied since the vaccine was approved. There is no information about the number that has received more than one dose – the vaccine needs three to be effective.
According to Homsani, people who have already taken one of the doses should normally complete the schedule to maintain protection. "The person who was seronegative and has been vaccinated has already received the vaccine.
We can not know if she was previously seronegative. In this case, you must complete the vaccination schedule. It does not make sense to stop because it has already received the antigens, "he says.
Those who have not yet started the scheme and want to be vaccinated must do tests to see if they have had contact with the virus, he reports.
THE DENGUE VACCIN Name: Dengvaxia
Manufacturer: Sanofi Pasteur (France)
Approved by Anvisa: December 2015
Application: three doses, one every six months
Indication: people between 9 and 45 years old, seropositive for dengue and living in endemic areas (where 70% or more people had dengue)
Contraindication: people who are seronegative for dengue, that is, who have never had contact with the virus, in addition to pregnant women, people with an increased risk of allergic reactions or low immunity, among others
Price in private clinics: up to R $ 138.53 per dose (an application can also be submitted)
In the public network: not available at national level
In other countries: it was approved in 19 countries (Brazil was the 2nd, after Mexico)