Even though dengue is endemic in Puerto Rico and that there is currently an emergency due to this virus, the Department of Health (DS, in Spanish) has not taken basic actions to prevent and protect citizens or provide guidance on the available vaccine for children between the ages of nine and 16, an investigation by the Center for Investigative Journalism (CPI) found.
The agency has only managed to fully vaccinate 19 children since the vaccine was introduced in Puerto Rico in 2022, which is less than 0.01% of the population in this age group, and almost all have been from San Juan.
To date, 1,033 cases have been reported since the beginning of the year, exceeding the expected epidemiological threshold. Most of the cases being seen are of a type of dengue for which most people in Puerto Rico do not have immunity, said Julieanne Miranda, associate director of the Puerto Rico Science, Technology, and Research Trust’s Vector Control Unit.
It is unknown how many of the more than 300,000 minors between the ages of nine and 16 would qualify for the vaccine, since large-scale screening tests are not carried out, which are essential because only those who have had dengue before receiving the doses can be vaccinated. The agency itself estimates that five out of every 10 children between those ages have had dengue in Puerto Rico, so about 150,000 minors would be eligible.
Few diagnostic tests have also been done. This year, the Health Department has carried out 3,327 molecular tests and 1,399 IgM (test that detects antibodies), according to data provided by the Office of the DS’s Chief Medical Officer. These tests are key to treating other lethal diseases that can be confused with dengue in time , such as leptospirosis, influenza, and malaria, said several infectious disease specialists interviewed.
The low number of diagnostic tests carried out by the DS responds to the lack of infrastructure to process the samples in Puerto Rico, said the experts and officials interviewed. The low vaccination rate is attributed to very few people knowing that this vaccine exists and to the logistical challenges for inoculation, according to the experts interviewed. Also, the DS recognizes in its own Strategic Plan for Integrated Vector Management published in 2023, that it does not have the resources, facilities, or technology necessary to address the dengue emergency.
For more than four months, cases have been exceeding what was expected and two months ago a dengue-related emergency was declared. Still, less than 20 children and teens among possible vaccination candidates have received the full dose, even though the vaccine has been available in Puerto Rico since 2022.
The DS’s trivial action in recent months adds to years of official abandonment of the dengue issue in Puerto Rico, despite predictions of an increase in the prevalence of the virus due to the jump in the mosquito reproduction rate because of the high temperatures generated by climate change at a global level. For example, a massive orientation campaign has not been kept up and periodic fumigation efforts in the municipalities have been reduced. In addition, the processing of diagnostic tests remains centralized in San Juan.
Samples taken in any hospital or laboratory must be sent to the DS for processing, and the result takes approximately a week, when it is no longer useful for the patient’s treatment.
“Many times we don’t receive the results until the patient is discharged,” said infectologist Miguel Colón.
“Easily, 90% of cases in Puerto Rico are discharged before we have the confirmatory test,” said the doctor.
The US Centers for Disease Control and Prevention (CDC) also processes them, but only for its internal investigations, not for the public.
Scarce and Ineffective Orientation
The scarce orientation the DS has provided citizens on the mosquito cycle and vaccination plays a leading role in the emergency declared in Puerto Rico, which already claimed its first fatality this year.
“Previously, these interactions were more effective since the method of communication with people was one: television, and you saw the ads, and you saw that, and it was easier,” said Dr. Lemuel Martínez, former president of the Infectious Disease Society, who believes that a similar campaign should be carried out through social networks.
ENG – Vectores by CPIThe infectious disease specialist believes the public should be guided on the “basic and simple methods [that] still work” to protect us against the mosquito that causes the disease and prevent its reproduction.
The DS has invested $14 million in advertising this fiscal year, according to the Comptroller’s Office’s Contract Registry, but the agency would not specify how much was allocated to prevention and orientation campaigns on dengue.
Although asked, the agency was also unable to provide evidence of any media campaigns on dengue, including vaccination, to prevent the viral infection caused by the mosquito. The only efforts it mentioned were orientation efforts on the agency’s website and social media posts in celebration of Mosquito Action Week. The CPI reviewed them and saw there have been only four publications in 2024 and they only address the issue of preventing mosquito breeding sites.
Health experts who spoke with the CPI said most of the population does not know about the vaccine for children, much less how and where it can be obtained.
Dr. Melissa Marzán, Chief Epidemiology Officer of the DS, said efforts are mainly directed at visits to communities. She said they are also training community health promoters on the issue of dengue so that they can support the DS in educational interventions in the community.
“There’s a very concrete effort in the community that seems to us to be perhaps one of the most important on the issue of dengue, because we can have the best plan, but if the community doesn’t welcome it, doesn’t accept it, don’t work on it, the truth is that it isn’t going to work,” Marzán added.
According to the agency’s promotional ads on Facebook, they began making weekly visits — mostly to schools and health fairs — in February. The agency has reached about 30,000 people from October 2023 to May.
On March 25, Health Secretary Carlos Mellado López issued a public health emergency declaration due to dengue.
The municipalities with the highest dengue incidence rates are Rincón, Canóvanas, Aguada, Carolina, and San Juan. The municipality with the highest number of accumulated cases for this period is San Juan, followed by Carolina, Rincón, Bayamón and Canóvanas. The municipalities of Carolina and Bayamón said they are fumigating and guiding citizens to eliminate breeding sites. The other municipalities did not respond to what measures, if any, they were taking.
The largest number of reported cases is in men and the age group with the most cases is 0 to 19 years, particularly the 10- to 19-year-olds group, which is a little more than 30% of the cases. To date there are 603 hospitalized, 59 severe cases, and one death of an 85-year-old man from the San Juan region.
Department of Health video Screenshot
After 18 weeks of surveillance in Puerto Rico, during the last 16, the cases have been above the threshold of what was expected and that is why it is classified as an epidemic, Marzán said. The official pointed out that although there may seem to be few cases, the Department of Health considers it an epidemic due to the historical behavior of the disease.
“[E]ach disease is evaluated according to its historical [pattern] and the disease,” Marzán said.
No Diagnostic Tests Available at Hospitals
Dr. Martínez said doctors must treat and care for the patient until the results of the dengue test arrive because this “isn’t a test that you have available, that you run in the hospital.” He emphasized that it is very important that doctors have these tools available in the hospital.
“You want to have the best diagnostic methods as available as possible. In the case of dengue, we haven’t yet been able to have this type of test available. We still depend on referring them to the Department of Health (in San Juan),” he said.
Although processing the sample only takes a few hours, the results take a week due to the bureaucratic processes and documents that must be completed.
“We haven’t yet been able to have that test available in Puerto Rico’s hospitals, or even in laboratories, in general. These types of tools, on a tropical island, where we have dengue year-round, and we’ve always had it, it would be ideal for us to be able to run the tests,” he said.
He said the speed with which these tests are carried out is important because there are diseases that could “disguise” themselves as others that present a similar clinical picture, such as leptospirosis or malaria — in the case of travelers — and dengue.
Infectious disease specialist Colón said it is common for doctors in Puerto Rico to diagnose patients with dengue when the diseases could be leptospirosis or influenza. He even mentioned that after Hurricane María there were diagnoses of dengue that were actually leptospirosis.
Looking ahead to the hurricane season, Colón is concerned that the diagnostic confusion will continue. “If we fail that diagnosis because we think that they have dengue, that we only have to give them liquids, our population will go through what happened with María, that we had many deaths from leptospirosis [which requires antibiotics] that could have been avoided,” he warned.
“If a patient comes to you with a headache, muscle aches, a very high fever, and low platelets, [doctors] have to look at the white blood cell count because, if it’s low, it’s dengue, but if it’s high, it’s leptospirosis and these patients deserve the use of antibiotics,” he said.
He explained that the leptospirosis test also takes two weeks, so these patients must be treated as if they had leptospirosis “before they go into kidney failure, liver failure, and pulmonary hemorrhage.”
“Usually there has been that conversation: If you suspect it, deal with it. But it’s not that easy, because you need to have the most accurate diagnoses, as soon as possible,” he said. “How we bring and make that technology available and that it works and that it reaches the patient, and the doctor who is managing it, is very important.”
For Dr. Iris Cardona, chief medical officer of the DS, a positive test or a test is not needed to decide how to treat the patient.
“You shouldn’t wait for a result. The result is important to convey what happened, for surveillance data, to know where we have a problem. But in reality, dengue has a clinical representation, diagnostic criteria, a specific definition, and classification that tells doctors, clinicians how to proceed. And that’s the most important thing,” she told CPI.
Meanwhile, Dr. Marzán acknowledged that one of the challenges to manage dengue is the way in which the public surveillance system was designed that centralized molecular diagnostic tests in the DS emergency laboratory. José Sánchez, former president of the Association of Clinical Laboratories, added that private laboratories also do not invest in the infrastructure necessary to process molecular tests because it is expensive, demand is low, and health insurance plans pay “$20” per test.
“There’s no way the laboratory can bring that machine to implement that test,” he said.
Marzán said they are looking to increase the capacity of the emergency laboratory and that the DS Public Health Laboratory also performs molecular tests.
The official also said that the agency is working so commercial laboratories can offer two types of dengue tests to expand the scope. Among these is the test known as NS1 (antigens), which, together with the IgM serological test, can confirm cases. She said there is already one clinical laboratory that has completed the validation process with the DS and that there are five others in the process.
The Risk of Not Following the Protocol
From September 6, 2022, to May 21, a total of 245 doses of dengue vaccine have been administered, according to data from the Office of the DS’s Chief Medical Officer. The information that the DS has been providing about this vaccine is very limited. It is only available on their website.
Dr. Gredia Huerta Montañez, pediatrician and co-founder and president of Puerto Rico Clinicians for Climate Action, pointed out that what is sought with this vaccine is to prevent minors from getting severe dengue fever, which is what happens in a second infection.
This vaccine was discontinued by the pharmaceutical manufacturer due to the low level of use, and what remains available will be administered until 2026, added Huerta Montañez. Currently, there are two other companies working on a dengue vaccine, said the pediatrician.
Infectious disease specialist Colón explained that, for the vaccine to have no side effects, the patient must have had dengue. The doctor explained that some studies showed serious effects, including death, in people who were vaccinated without ever having contracted dengue prior to vaccination.
“That’s why this vaccine has never had a massive boom,” Colón analyzed. “I’m pro-vaccine, but not this vaccine,” he said, explaining that if dengue is treated properly, the risks are minimal.
On the other hand, Dr. Martínez does support the vaccine, although he recognizes the logistical limitations that exist for vaccination.
A patient can confirm if they have had dengue fever through screening tests and determine if they are suitable for dengue vaccination. The private Toledo Clinical Laboratory is working with these tests and has “helped” the DS to promote the vaccine by publishing billboard ads, said Ilia Toledo, president of the Laboratory. She assured that the promotion has resulted in calls from the public seeking guidance.
“We wanted to help the Department of Health in that sense. And, although we didn’t vaccinate, we did it to offer guidance to the public and I think it has had that effect because they have really called us asking,” said the medical technologist, who explained that many people don’t know about the existence of the dengue vaccine.
Dr. Cardona explained that the two screening tests required before vaccination are different from those for diagnosing the disease. She said the 330 Health Centers were chosen to oversee the inoculation because a pediatrician, a laboratory, and coordination with the reference laboratories that are needed, and the vaccination clinic are all under one roof.
Vector Control in Puerto Rico
Currently, the dengue that is most prevalent in Puerto Rico is serotype 3, said Dr. Julieanne Miranda, associate director of the Puerto Rico Science, Technology and Research Trust’s Vector Control Unit.
“Many years ago, in Puerto Rico there was no dengue 2 and 3. The last epidemic was dengue 1 in 2010-2012. So, what’s happening? There are many people who have immunity to this serotype. Now we’re seeing more type 3 because there are more susceptible people, that’s why more people are infected,” Miranda said. As there are fewer people who have previously been infected with that virus, with that serotype, there is less immunity “and that worries us because since it’s a serotype that we haven’t seen for more than 20 years in Puerto Rico, more people can become infected, so the epidemic can spread quickly,” she added.
Photo by Brandon Cruz González | Centro de Periodismo Investigativo
Gabriela Paz Bailey, head of the Dengue Branch of the CDC, agreed that the serotypes that currently predominate are 2 and 3.
“When you are infected with a type of dengue, you have lifelong protection. If I get infected with dengue 1, I will never get sick (with that type) again. If I was infected with dengue 1, I’m still susceptible to the other serotypes because the protection is only from the serotype that the person was infected with. And one of the most important risk factors for severe dengue disease is the second time that a person is infected with a serotype different from the first,” Paz Bailey explained.
Another factor that strengthens the epidemic is the accumulation of water due to rain during the months of March, April, and May. The adult female mosquito, which is the one that bites, lays its eggs on the walls of containers with accumulated water. Miranda said the repeated episodes of rain in recent months led to the transmission of dengue earlier than in other years.
The Health Department Says it has No Resources
The Health Department is dealing with challenges related to having no funds for vector control and a shortfall of human and material resources, according to the Strategic Plan for the Integrated Vector Management of Puerto Rico 2023.
Furthermore, according to this document, the physical facilities are deficient and lacking in technology and the agency lacks an entomological laboratory.
The agency also acknowledges that the actions they take to control vectors are reactive and not proactive because they act in accordance with epidemiological surveillance. They also lack regulations for a control process on vector control management and don’t have education or community orientation programs on a recurring basis.
Given the deficiencies that the Department of Health recognizes in its plan for vector management, Mayra Toro, assistant secretary of the Environmental Health Division of the DS, said collaboration agreements were established with the Puerto Rico Science, Technology and Research Trust’s Vector Control Unit in Puerto Rico to address the entomological part, with the CDC, and with the municipalities.
Meanwhile, Toro explained that for vector control to take place in the communities the priority is to identify the breeding site, treat it with the use of larvicides or eliminate it if possible, and as a last resort, fumigation is used.
She said that since late 2023, fumigation has been carried out in nine of Puerto Rico’s 78 municipalities: Loíza, Bayamón, San Juan, Guaynabo, Canóvanas, Río Grande, Rincón, Aguada, and Las Piedras.
The Effects of Climate Change
Huertas said it is common knowledge that the frequency of epidemics, such as those caused by dengue, can increase with climate change.
She said the mosquito changes its behavior with high temperatures, and has a shorter life cycle, in which it can go from egg to adult mosquito in a shorter period, so it has a greater reproduction capacity.
“This isn’t going to be a once-and-done thing. We know that in the immediate and long-term future we must learn how to control the mosquito,” she pointed out.
Photo by Brandon Cruz González | Centro de Periodismo Investigativo
Meanwhile, Paz Bailey said Puerto Rico has the ideal environment for Aedes aegypti, due to the climate, rain, and heat.
“It’s a paradise island, but it’s also a paradise for mosquitoes. There is a fairly robust population of Aedes aegypti in Puerto Rico,” said the CDC official. “Aedes aegypti is an imported species. It didn’t exist here originally, but it has been established for many years,” she said.
She even mentioned that the increase in temperatures due to climate change has contributed to Aedes aegypti populations growing and expanding into areas where the mosquito was not previously present.
“In the case of the United States, Arizona reported two locally acquired cases in 2022 and California two cases in 2023. Previously [these states] had only had cases associated with travel, now they have had locally acquired cases,” Paz Bailey warned.
The head of the CDC’s Dengue Division said that in Europe, cases of the viral infection have also been reported for the first time in Italy, France, and Spain.
Paz Bailey said it’s difficult to predict the incidence of dengue in the future because it depends on a combination of climate and immunity in the population.
“At a global level, it’s expected that dengue will be more common, that it will be reported in areas where it had not been reported before, and that areas that are endemic for dengue [such as Puerto Rico], which have had dengue historically, will have more frequent outbreaks,” said the specialist on the matter.
