After the suspension of the national campaign to immunize children against dengue fever by the Philippine government, faced with a popular and political emotion, Sanofi Pasteur announced that he will reimburse Dengvaxia for unused doses in Manila. He will also propose a modification of the notice.
Sanofi Pasteur will reimburse the Philippine government for unused doses of a dengue vaccine. Manila has suspended the vaccination campaign because of concerns about the death of 14 children as a result of the vaccination.
Sanofi Pasteur pointed out that this reimbursement had nothing to do with vaccine safety issues and aimed to improve its relationship with the Philippine Ministry of Health, which is investigating the deaths of these children as a result of vaccination with the vaccine. Dengvaxia.
Dengue fever or tropical flu
Dengue, also called "tropical flu", is a tropical haemorrhagic fever linked to an arbovirus, transmitted by a mosquito of the genus Aedes.
WHO estimates that there are 50 million annual cases worldwide, including 500,000 cases of dengue hemorrhagic fever, which are fatal in more than 2.5% of cases. Originally present in the tropical and subtropical areas of the world, dengue now affects Europe where the first indigenous cases have been recorded.
Strains of dengue virus are divided into four distinct serotypes: DEN-1 to DEN-4. Immunity acquired in response to infection with one serotype confers protective immunity only against this infecting serotype but not against other serotypes. As a result, a person is likely to be infected with each of the four dengue serotypes in his lifetime. Subsequent infections with other serotypes would increase the risk of developing a severe dengue, known as "haemorrhagic".
The vaccine produced by the French laboratory Sanofi Pasteur is licensed in Mexico, Brazil, El Salvador and the Philippines to protect the 9-45 years of this potentially deadly virus. The particularity of this vaccine is its ability to immunize individuals against the four strains of the dengue virus with an efficiency between 56 and 60%.
Two forms of dengue
"Classic" dengue occurs suddenly after 2 to 7 days of incubation with a high fever with headache, nausea, vomiting, joint and muscle pain and a rash like measles. A brief remission is observed after 3 to 4 days, then the symptoms intensify, conjunctival haemorrhages, nosebleeds or bruises may occur, before regressing quickly after one week and a recovery that can last Several weeks.
Dengue "haemorrhagic", which represents about 1 to 2.5% of cases, is extremely severe: the fever persists and multiple haemorrhages gastrointestinal, cutaneous and cerebral occur. Especially in children under the age of fifteen, a state of hypovolemic shock can set in, cause abdominal pain and cause death if the patient is not resuscitated. There is no specific treatment against the virus.
Concerns about the vaccine
In the Philippines, from April 2016, Dengvaxia was widely used as part of the national immunization campaign until, in December 2017, the government expressed its concerns.
After Sanofi announced that the vaccine could worsen the disease in people who have never had a dengue fever and are infected with the virus for the first time, an emotion has seized Philippine public opinion.
Parents then declared that the vaccine was responsible for the death of their child (14 cases). Although there is no direct link between vaccination and child deaths to date, Filipino parliamentarians have gone so far as to accuse the government of knowingly putting the health of children at risk. In total, nearly 830,000 children received the vaccine.
An investigation in the Philippines
After the death of these 14 children who received Dengvaxia, the Philippine government opened an investigation. In December 2017, he also announced that he would be asking Sanofi Pasteur for reimbursement of 22.8 million euros for unused doses.
Sanofi Pasteur, the group of the group in charge of vaccines, which announced Monday that a refund was planned, said that this decision was "unrelated to any safety issues or quality of Dengvaxia." In the same press release, Sanofi Pasteur states that "the general benefits of dengue vaccination remain positive in countries where the disease is highly endemic like the Philippines".
A change of instructions
Dengvaxia is currently indicated in most countries for people aged nine and over who live in areas where dengue fever is highly endemic. This vaccine prevented 93% of serious illnesses and 80% of dengue hospitalizations in the 25 months of clinical trials in ten countries in Latin America and Asia where dengue fever is prevalent. widespread.
In the light of the latest analysis, Sanofi will propose to national regulatory agencies to update the package leaflet and ask health professionals to assess the likelihood of prior dengue infection in their patients before proceeding to the vaccination. The latter should be advocated only when its potential benefits outweigh its risks (in countries where the burden of disease is high) and is not recommended for people with no history of dengue infection.