The outbreak of dengue fever that has unfolded in Latin America over the previous three months is staggering in its scale — one million instances in Brazil in a matter of weeks, an enormous spike in Argentina, a state of emergency declared in Peru, and now one other, in Puerto Rico.
It forewarns of a altering panorama for the illness. The mosquitoes that unfold dengue thrive in densely populated cities with weak infrastructure, and in hotter and wetter environments — the kind of habitat that’s increasing shortly with local weather change.
Greater than 3.5 million instances of dengue have been confirmed by governments in Latin America within the first three months of 2024, in contrast with 4.5 million in all of 2023. There have been greater than 1,000 deaths to this point this yr. The Pan-American Well being Group is warning that this can be the worst yr for dengue ever recorded.
The quickly shifting illness panorama wants new options, and researchers in Brazil delivered the lone shred of excellent information on this story with the current announcement {that a} scientific trial of a brand new dengue vaccine, delivered in a single shot, had offered sturdy safety towards the illness.
There are two present vaccines for dengue, however one is an costly two-shot routine, whereas the opposite can solely be given to individuals who have already had a dengue an infection.
The brand new one-shot vaccine makes use of dwell, weakened types of all 4 strains of the dengue virus, and it was created by scientists on the Nationwide Institutes of Well being in the USA. The vaccine was licensed for improvement by the Instituto Butantan, an enormous public analysis institute in São Paulo, and Merck & Co.
Butantan will make the vaccine. It already produces a lot of the immunizations utilized in Brazil, and has the capability to make tens of thousands and thousands of doses of this new one. The institute plans to submit the dengue vaccine to Brazil’s regulatory company for approval within the subsequent few months and will start producing it subsequent yr.
However that received’t assist with this outbreak, and by the point the manufacturing gears up and a nationwide rollout will get began, it will not be sufficient to assist with the following one, both; dengue sometimes surges in three- or four-year cycles.
And it received’t essentially be of assist to the remainder of Latin America: Butantan will solely make the vaccine for Brazil. Different international locations within the area battling dengue must buy it from Merck, which has not mentioned what it plans to cost for the shot.
And there’s, in fact, demand for a dengue vaccine past the Americas: mosquitoes are spreading the illness to Croatia, Italy, California and different areas that haven’t seen it earlier than. Locations used to dealing with gentle outbreaks now face record-breaking ones: Bangladesh had 300,000 instances final yr.
Dengue is often identified by the identify breakbone fever, after the excruciating joint ache it causes. Not all people experiences that ache: Three-quarters of individuals contaminated with dengue don’t have any signs in any respect, and amongst those that do, most instances resemble solely a gentle flu.
However about 5 p.c of people that turn out to be sick will progress to what’s known as extreme dengue. Plasma, the protein-rich fluid element of blood, can begin to leak out of blood vessels, inflicting sufferers to enter shock or endure organ failure.
When sufferers with extreme dengue are handled with blood transfusions and intravenous fluids, the mortality fee tends to be between 2 and 5 p.c. However once they don’t get remedy — as a result of they don’t notice it’s dengue and don’t search remedy shortly sufficient, or as a result of well being facilities are overwhelmed — the mortality fee is 15 p.c.
In Brazil, the present dengue outbreak is hitting kids hardest; these below 5 have the best mortality fee of any age group, adopted by these aged 5 to 9. Adolescents between 10 and 14 have the best variety of confirmed instances, based on the Instituto Oswaldo Cruz, a nationwide public well being analysis heart.
As clinics started to be overwhelmed with dengue sufferers in January, the Brazilian authorities purchased the whole international inventory of a Japanese-made vaccine for dengue known as Qdenga. Public well being nurses are delivering it to kids ages 6 to 16, however there’ll solely be sufficient vaccine to totally vaccinate 3.3 million of Brazil’s 220 million individuals this yr.
This massive nationwide effort will shield a couple of million kids, however it received’t contribute something to its herd immunity.
Qdenga will not be low cost: It’s about $115 per dose in Europe and $40 in Indonesia. Brazil is paying $19 per dose, having negotiated a cheaper price for its large buy.
Takeda Prescription drugs, which makes Qdenga, introduced a deal final month with Organic E, a big Indian generic drug maker, to license and produce as much as 50 million doses a yr, a part of a race to speed up manufacturing. The Indian vaccine ought to value significantly much less. However Organic E is unlikely to have regulatory approval to promote it earlier than 2030; it’s a gradual course of that entails transferring expertise, organising a manufacturing line and getting a brand new model of even a well known product accredited by regulators.
Dengue prices Brazil at the least $1 billion a yr in well being care remedy and misplaced productiveness. And that determine doesn’t keep in mind the human struggling concerned.
There 4 totally different strains of the dengue virus complicate greater than the method of creating a vaccine: the possibly deadly type of the illness is extra widespread when an individual has a second an infection, with a unique pressure than that they had the primary time. Qdenga protects towards all 4 strains of dengue, and the hope is that the brand new Butantan vaccine does too, though the information launched to this point present it examined solely towards the 2 varieties that have been circulating in the course of the first a part of the trial; extra outcomes are anticipated in June.
Hundreds of thousands extra individuals may have been uncovered to dengue when this outbreak lastly passes. However they’re going to wish that new vaccine extra urgently than ever.
