Title: Panama’s Health Ministry Halts Dengue Vaccine Acquisition, Citing Lack of Robust Evidence and High Efficacy Threshold
The Ministry of Health (Minsa) in Panama has decided not to acquire the dengue vaccine, Qdenga (TAK-003), at this time. The ministry cited two primary reasons for this decision. First, Minsa stated that there is not yet sufficient evidence demonstrating the vaccine’s effectiveness against the four circulating dengue virus serotypes in Panama. Secondly, the ministry is waiting for a vaccine with at least 90% to 95% efficacy against all four serotypes before proceeding, and will continue to monitor the recommendations of the World Health Organization (WHO) and the Pan American Health Organization (PAHO).
Qdenga: A Promising Vaccine
Qdenga, developed by Japanese pharma giant Takeda, was evaluated in Panama by a team of scientists at the Cevaxin research center. The clinical trials involved 3,000 local volunteers and lasted for five years. The vaccine demonstrated safety and efficacy in the Panamanian population, according to Dr. Xavier Sáez-Llorens, an infectologist, pediatrician, and clinical researcher at Cevaxin.
While acknowledging that many vaccines in use globally, such as BCG, pertussis, influenza, and malaria, do not exceed 90% efficacy, Dr. Sáez-Llorens highlighted their significant impact on public health by reducing hospitalizations and deaths. In this context, Qdenga could also have a relevant impact, he suggested.
The WHO has recommended the use of Qdenga in regions with a seroprevalence of 60% or more and high transmissibility, such as Panama. In the absence of seroprevalence studies, the recommendation is based on high hospitalization rates among adolescents, a current trend in Panama.
However, Qdenga is ineffective against serotype 3 in dengue-naive individuals, and data for serotype 4 is limited due to its low circulation during trials. In seropositive subjects, the vaccine is effective against all four serotypes. In Panama, serotypes 1 and 2 are most prevalent, and Qdenga has shown high efficacy against them.
Expert Opinions Divide
Dr. Sáez-Llorens believes that while Qdenga’s impact on public health might be moderate due to the need for mass immunization to maximize its effect, individual protection against hospitalization and death would be significantly elevated.
On the other hand, Dr. Javier Nieto, an infectologist and former director of the Institute Conmemorativo Gorgas de Estudios de la Salud (ICGES), criticized the ministry’s decision. He argued that even with a low efficacy rate, the widespread prevalence of dengue makes the vaccine beneficial for public health by reducing cases and potential hospitalizations.
Dr. Nieto also noted that serotype circulation can vary annually, and the vaccine’s purpose remains to reduce the disease’s specific burden. Furthermore, he emphasized the insufficiency of current disease reduction measures and the necessity of additional preventive tools.
Dengue in Panama and the Region
As of the 51st epidemiological week (December 15-21, 2024), Panama has recorded 31,605 dengue cases and 52 deaths. Over 2,600 hospitalizations have been reported, with the majority occurring in the Metro, Panama Oeste, and Colón regions.
This dengue outbreak is not exclusive to Panama. In 2024, Latin America has experienced its largest dengue epidemic since 1980, with over 12.6 million cases, 21,000 severe cases, and at least 7,700 deaths. Argentina, Brazil, Colombia, and Mexico account for 90% of these cases, with Brazil reporting the highest figures.
The dengue vaccine is available in Brazil (both public and private systems), Argentina, and Colombia (private), while several Asian countries offer it in the private sector, and some European nations provide it for travelers.
Brazil began vaccinating its population for dengue in February 2024, focusing on high-risk areas. The WHO approved the vaccine in May 2024 and recommended its use in children aged 6 to 16 in regions with high dengue prevalence. The vaccine, administered in two doses, protects against all four dengue serotypes.
