The dengue fever outbreak that has erupted in Latin America over the past three months has been staggering in scale – a million cases in Brazil in a matter of weeks, a spike in Argentina, a state of emergency declared in Peru and now another state of emergency. , in Puerto Rico.
It heralds a changing landscape for the disease. The mosquito that transmits dengue thrives in densely populated cities with weak infrastructure and in warmer and wetter environments – the type of habitat that is expanding rapidly with climate change.
More than 3.5 million cases of dengue fever have been confirmed by governments in Latin America in the first three months of 2024, compared with 4.5 million cases in all of 2023. Year to date Today, there have been more than 1,000 deaths. Pan American Health Organization are warning that this could be the worst year for dengue fever on record
The rapidly changing disease landscape needs new solutions, and researchers in Brazil provided the only good news in this story with the recent announcement that a clinical trial of a fever vaccine New hemorrhage, performed in a single injection, was performed. provides strong protection against this disease
There are currently two types of dengue vaccines, but one is an expensive two-shot regimen, while the other can only be given to people who have already been infected with dengue.
New one-shot vaccine uses live, weakened forms of all four dengue virus strains and it was created by scientists at the US National Institutes of Health. The vaccine has been licensed for development by Instituto Butantan, a major public research institute in São Paulo, and Merck & Co.
Butantane will create a vaccine. It already produces most of the vaccines used in Brazil and has the capacity to produce tens of millions of doses of this new vaccine. The institute plans to submit the dengue vaccine to Brazilian regulators for approval in the next few months and could begin production next year.
But that won't help this outbreak, and by the time manufacturing begins and a nationwide rollout begins, it may not be enough to support the next outbreak either; Dengue fever usually increases in three or four year cycles.
And it won't necessarily help the rest of Latin America: Butantan will only produce vaccines for Brazil. Other countries in the region struggling with dengue fever will have to buy the vaccine from Merck, which has not said how much it plans to charge for the vaccine.
And of course, there is demand for a dengue vaccine beyond the Americas: mosquitoes are spreading the disease to Croatia, Italy, California and other areas where it has never been seen before. Places that once dealt with mild outbreaks now face record outbreaks: Bangladesh had 300,000 cases last year.
Dengue fever is commonly known as fracture fever, after the severe joint pain it causes. Not everyone experiences that pain: Three-quarters of people with dengue fever don't have any symptoms, and among those who do, most cases are just mildly flu-like.
But about 5% of people with the disease will develop severe dengue fever. Plasma, the protein-rich liquid component of blood, can begin to leak out of blood vessels, causing the patient to go into shock or organ failure.
When patients with severe dengue fever are treated with blood transfusions and intravenous fluids, the mortality rate tends to be between 2 and 5%. But when they don't get treatment – either because they don't realize it's dengue and don't seek treatment quickly enough or because health centers are overwhelmed – the mortality rate is 15%.
In Brazil, the current dengue outbreak is affecting children the hardest; Children under 5 years old have the highest mortality rate of any age group, followed by children 5 to 9 years old. Youth ages 10 to 14 have the highest number of confirmed cases, according to the Oswaldo Cruz Institute a national public health research center.
When clinics started being flooded with dengue patients in January, The Brazilian government has purchased the entire global stock of Japanese-made vaccines for dengue fever is called Qdenga. Public health nurses are providing vaccines to children ages 6 to 16, but there will only be enough vaccines to fully vaccinate 3.3 million of Brazil's 220 million people this year.
This massive national effort will protect several million children, but it will contribute nothing to herd immunity.
Qdenga isn't cheap: It costs about $115 per dose in Europe and $40 in Indonesia. Brazil is paying $19 per dose after negotiating a lower price for its huge purchases.
Takeda Pharmaceuticals, the company that makes Qdenga, announced a deal last month with Biology E, a major Indian generic drugmaker, to license and manufacture up to 50 million doses per year, part of a racing to speed up production. India's vaccine will cost significantly less. But Biologics E is unlikely to get regulatory approval to bring it to market before 2030; it is a slow process that involves transferring technology, setting up production lines and creating new versions of even a well-known product that has already been approved by regulators.
Dengue causes damage to Brazil at least 1 billion USD per year in healthcare treatment and loss of productivity. And that number doesn't take into account the human suffering involved.
There are four different strains of the dengue virus that are more complicated than the vaccine process: the potentially fatal form of the disease is more common when a person is infected a second time, with a different strain than the first time . Qdenga protects against all four strains of dengue fever and it is hoped that the new Butantan vaccine will do the same, although data published so far suggests it tested only the two types circulating in the region. first test; More results are expected in June.
Millions more people will be exposed to dengue fever when this outbreak finally passes. But they will need that new vaccine more urgently than ever.