Dengue Fever in the Cayman Islands 2023
Posted by dkwinter

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Dengue Fever in the Cayman Islands

Dengue is a viral illness caused by four distinct strains of the dengue virus spread by the Aedes aegypti mosquito

  • The illness is usually asymptomatic or mild
  • Individuals develop immunity to each specific strain after being infected
  • Symptoms usually develop 5-6 days after the bite of an infected mosquito (range of 3-15 days)
  • Symptomatic cases are classified into three categories
    • Dengue fever (DF) (aka “break-bone fever")
      • Defined by fever plus ≥2 of:
        • Headache
        • Retro-orbital or ocular pain
        • Myalgia and/or bone pain
        • Arthralgia
        • Rash
        • Hemorrhagic manifestations (abnormal bleeding)
        • Leukopenia
    • Dengue hemorragic fever (DHF)
      • DF (lasting 2-7 days, usually biphasic) complicated by evidence of (all 3):
        • 1. Increased vascular permeability (+tourniquet test)
        • 2. Thrombocytopenia
        • 3. Evidence of plasma leakage (↑Hct, ↓Hct following hemodilution, signs of plasma leakage (e.g. ascites, pleural effusion, or hypoproteinemia))
    • Dengue shock syndrome (DHF+shock)



  • There is no specific treatment
  • Use acetaminophen to treat fever (≥38°C, 100.4°F)
  • Do not use aspirin or any NSAID due to bleeding risk Increase hydration
  • Increase mosquito precautions to prevent further transmission
  • Most patients will recover without complications

When should I seek medical attention?

Any persistent high fever (≥39°C, 102.2°F) that will not come down despite appropriate doses of acetaminophen

  • Severe abdominal pain
  • Bleeding of nose or gums
  • Black stools
  • Drowsiness
  • Absence of urine output for >6 hours during the day despite attempts at hydration

Is there a test?

  • Yes, serum antigen and antibody (IgM and IgG) tests exist

Do I need to get tested?

  • Not unless concerning symptoms develop (above), which warrant medical attention

Is there a vaccine?

  • No*, the only protection comes from avoiding mosquito bites


*The problem with vaccines for Dengue fever has been the phenomenon of ADE: antibody-dependent enhancement of infection (ADE), "which occurs when viruses bound to sub-neutralizing antibodies are opsonized by immune cells like dendritic cells, monocytes/macrophages through Fc receptor, which then results in increased virus production." In other words, these vaccines create antibodies that (without the help of natural antibodies from prior infection) cannot totally clear the infection and instead actually enhance replication of the virus.

A vaccine called Dengvaxia exists but is only for patients who have had a previous lab-confirmed case of Dengue fever (DF) as patients without such history actually have worse outcomes from DF after infection.

Qdenga, is a new live-attenuated vaccine for dengue approved in the UK for broad use in February 2023. It is given in two doses, 3 months apart, and has been shown to decrease fever for 12 months following the second injection and decreased hospitalizations and symptomatic cases after 4.5 years. However, there remains concern for ADE from Qdenga: "seronegative patients showed higher hospitalization rate (0.2%) compared to placebo (< 0.1%) for DENV-3 infection [123], raising concerns that serostatus might also affect safety outcomes with this vaccine, similarly to Dengvaxia."

In July, the manufacturer withdrew their application for FDA approval citing data problems.

At this time, there are no society or college guidelines for who should get Qdenga.

Given that most cases of dengue are mild, that the vaccine is live attenuated (high chance of a viral syndrome after vaccination), that benefits only come from after the second dose, and that it may cause worse outcomes in patients who have not previously been infected with dengue, I would not recommend it for general use at this time.

Hopefully, enough safety data will become available to convince the FDA and medical colleges and societies to support Qdenga or that other new Dengue fever vaccines come along to meet this important area of need.

Of course, individual circumstances vary and you should always discuss with your own family physician, who knows you best.