Dengue Fever in depth.
The world's most prevalent mosquito-borne viral disease — 400 million infections per year, four serotypes, and the dangerous paradox of secondary infection.
Overview
Dengue fever is a mosquito-borne viral disease caused by four antigenically distinct serotypes (DENV-1 to DENV-4). Caused by dengue virus (Flaviviridae), it spreads through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. Key symptoms: sudden high fever (39–40°C), severe headache, retro-orbital pain, and intense joint and muscle pain. Most cases resolve within 7–10 days; severe dengue (dengue shock syndrome) carries a case fatality rate of up to 20% without treatment.
With an estimated 390–400 million dengue infections occurring annually (of which roughly 100 million result in clinically apparent disease), dengue is the most common arboviral infection in the world. The global burden has increased dramatically — a roughly 30-fold increase in reported cases over the past 50 years — driven by rapid unplanned urbanization, global travel, climate change, water storage practices that create breeding sites, and inadequate vector control. Dengue causes approximately 40,000 deaths annually, the vast majority in children and adolescents in low- and middle-income countries.
The clinical severity of dengue varies enormously. Most infections (approximately 75%) are asymptomatic or subclinical. Symptomatic dengue ranges from undifferentiated fever to classic dengue fever, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). A key biological peculiarity of dengue is that while first infection with any serotype produces protective immunity to that serotype, sequential infection with a different serotype paradoxically increases the risk of severe disease through antibody-dependent enhancement (ADE).
History & Origin
Dengue-like illness was first recorded in Chinese medical encyclopaedia during the Jin Dynasty (265–420 AD). The first credible epidemic accounts date to 1779 in Asia and Africa, followed by a major pandemic affecting Philadelphia, Cairo, and Batavia in 1780. The disease was long known as "breakbone fever" because of its excruciating muscle and joint pain. The causative dengue viruses were isolated in 1943–1945 by Japanese and American researchers, and all four serotypes were characterized by 1956.
The post-World War II era saw dramatic increases in dengue incidence, particularly in Southeast Asia where rapid urbanization created ideal conditions for Aedes aegypti proliferation. The first dengue hemorrhagic fever epidemic was recognized in Manila in 1953, followed by Bangkok in 1958. By the 1970s, DHF had become a leading cause of pediatric hospitalization and death across Southeast Asia. In 2024, dengue reached unprecedented geographic spread — Brazil alone reported over 6 million cases in the first half of 2024, the worst outbreak in its recorded history.
Transmission
Dengue virus is transmitted to humans through the bite of an infective female Aedes mosquito. The mosquito acquires the virus when feeding on a viremic person; after an extrinsic incubation period of 8–12 days within the mosquito, it can transmit the virus to the next person it bites. Dengue is not directly contagious between people.
- Primary vector: Aedes aegypti — a highly domesticated species breeding in artificial water containers (tyres, flower pots, water storage jars, discarded containers) in and around human habitats; bites most actively 2 hours after sunrise and several hours before sunset.
- Secondary vector: Aedes albopictus (Asian tiger mosquito) — more cold-tolerant, enabling dengue spread into temperate Europe, North America, and higher altitudes.
- Viremia in the infected person lasts about 4–5 days (days 1–5 of illness); mosquitoes biting during this window can become infected.
- Climate change is expanding the range of Aedes aegypti and albopictus into previously dengue-free latitudes and altitudes.
Symptom Timeline
The incubation period is 4–10 days (most commonly 5–7 days). WHO classifies dengue into dengue with or without warning signs, and severe dengue.
- Sudden high fever (39–40°C / 102–104°F), often biphasic ("saddleback" pattern)
- Severe frontal headache, especially behind the eyes (retroorbital pain)
- Severe muscle, joint, and bone pain — hence "breakbone fever"
- Nausea, vomiting, loss of appetite
- Flushed face, early transient skin rash in some patients
- Positive tourniquet test (≥10 petechiae per 1 cm² after blood pressure cuff inflation)
- Abdominal pain or tenderness — especially in the right upper quadrant (liver area)
- Persistent vomiting (3 or more times in 24 hours)
- Clinical fluid accumulation (pleural effusion, ascites, rapid breathing)
- Mucosal bleeding: gums, nose, petechiae (red dots under skin), easy bruising
- Rapid platelet count fall (thrombocytopenia below 100,000/mm³)
- Lethargy, restlessness, sudden behaviour change
- Liver enlargement >2 cm; rising haematocrit ≥20% above baseline (hemoconcentration)
- Rapid, weak pulse; narrow pulse pressure (<20 mmHg)
- Hypotension, cold and clammy skin, pale appearance
- Severe plasma leakage causing circulatory collapse
- Severe bleeding: haematemesis (vomiting blood), melena (black tarry stool)
- Organ impairment: liver (hepatitis), CNS (encephalopathy), heart (myocarditis), kidneys
- Reabsorption of plasma — risk of fluid overload if receiving IV fluids
- Bradycardia (slow heart rate) is common in recovery
- Classic maculopapular rash ("islands of white in a sea of red")
- Generalised itching (pruritus)
- Platelet count gradually recovers to normal within 1–2 weeks
- Fatigue and weakness may persist 2–4 weeks after acute illness
Diagnosis
- NS1 antigen test: Detects dengue non-structural protein 1 present in serum from days 1–5. Sensitivity 50–90%. Rapid point-of-care tests widely available in endemic areas.
- IgM/IgG serology (ELISA): IgM antibodies appear from day 3–5, confirming recent dengue. IgG indicates prior infection. In secondary infections, IgG rises rapidly before IgM.
- RT-PCR: Highly sensitive and specific; identifies serotype; most useful in the first 5 days. Reference standard for surveillance. Requires laboratory infrastructure.
- Full Blood Count (FBC): Thrombocytopenia (platelets <100,000/mm³) and leukopenia (low white blood cells) are characteristic of dengue. Rising haematocrit ≥20% above baseline indicates plasma leakage.
- Liver enzymes (AST/ALT): Elevated in most dengue cases; severe elevation (>1000 U/L) indicates dengue hepatitis.
- Chest X-ray / Ultrasound: May reveal pleural effusion, ascites, or gallbladder wall thickening — markers of plasma leakage in severe cases.
WHO diagnostic criteria for severe dengue require at least one of: severe plasma leakage leading to shock or respiratory distress, severe bleeding, severe organ impairment (liver, CNS, heart, kidneys).
Treatment
No specific antiviral drug exists for dengue. Management is entirely supportive and depends on the clinical phase.
Mild Dengue (Home Management)
- Paracetamol (acetaminophen): First-line for fever and pain. Maximum 4g per 24 hours in adults. NSAIDs (ibuprofen, aspirin, naproxen) are strictly contraindicated — they inhibit platelet function and increase bleeding risk.
- Oral rehydration: Liberal fluid intake (water, oral rehydration salts, coconut water, fresh fruit juice without sugar) to prevent haemoconcentration. Target: minimum 5 glasses of fluid per day.
- Rest: Avoid strenuous activity during the acute phase.
- Monitoring: Daily FBC if possible; return to hospital immediately if any warning signs appear.
Dengue with Warning Signs (Hospital)
- IV fluid therapy: Isotonic crystalloids (Ringer's lactate preferred, or normal saline) given at rates adjusted to maintain adequate urine output (0.5–1 mL/kg/hr) without over-hydration.
- Haematocrit monitoring: Every 4–6 hours; rising haematocrit guides fluid titration.
- Platelet transfusion: NOT routinely recommended, even with very low counts (<20,000/mm³) if there is no significant active bleeding — counts recover spontaneously.
Severe Dengue / DSS (ICU)
- Aggressive fluid resuscitation with isotonic crystalloids; colloids (dextran, starch) if haematocrit does not improve.
- Oxygen supplementation; mechanical ventilation if needed for ARDS.
- Blood transfusion for significant haemorrhage (haematocrit falling with active bleeding).
- Careful fluid management during recovery phase to prevent pulmonary oedema from fluid reabsorption.
Prevention & Vaccines
- Dengvaxia (CYD-TDV, Sanofi Pasteur): Live recombinant tetravalent vaccine approved in 20+ countries for individuals 9–45 years with prior dengue infection confirmed by serology. Contraindicated in dengue-naive individuals. The 2017 Philippines school vaccination controversy led to major regulatory consequences.
- Qdenga (TAK-003, Takeda): EU-approved (2022), available in Indonesia, Brazil, and others. Phase 3 trials: ~73% overall efficacy, ~84% against hospitalised dengue. Does not require pre-screening. Recommended for ages 6–16 in EU endemic settings.
- Wolbachia mosquitoes: Mass release of Aedes aegypti infected with Wolbachia bacteria reduces dengue transmission. A 2021 NEJM trial in Indonesia showed 77% reduction in dengue cases.
- Personal protection: DEET (30–50%) repellents; long-sleeved clothing; permethrin-treated clothing; bed nets for daytime naps; window and door screens.
- Environmental control: Eliminate standing water (tyres, flower pots, water storage containers) around homes; community-level larviciding and fogging.
Global Impact
Dengue is the most prevalent arboviral disease in the world. The WHO estimates 390–400 million dengue infections occur annually. Approximately 40,000 people die from dengue each year, predominantly children in low- and middle-income countries.
The geographic range of dengue has expanded dramatically over the past two decades. Countries previously dengue-free — including Portugal's Madeira island (2012), France and Croatia (2020s), and parts of the southern United States — have seen locally acquired cases as Aedes albopictus establishes itself in temperate regions. Climate models predict that by 2080, more than 6 billion people could live in dengue-suitable climates.
The economic burden is massive: direct and indirect costs of dengue in the Americas alone are estimated at $2.1 billion annually. In 2024, Brazil experienced a national dengue emergency with over 6 million cases and more than 1,200 deaths in the first half of the year. Peru, Argentina, Paraguay, and Bangladesh also reported record outbreaks, reflecting the ongoing and intensifying global threat posed by dengue.
Dengue's global expansion is driven by climate change extending the range of Aedes mosquitoes, rapid urbanisation creating ideal breeding sites, international air travel spreading the virus between countries, and lack of universal access to clean water pushing communities to store water in containers. The Wolbachia biocontrol approach offers one of the most promising new tools for control at scale, with ongoing deployments in 13+ countries.
Country-Specific Information
Frequently Asked Questions
Sources & Citations
Dengue Grading & WHO Classification
WHO 2009 dengue guidelines replaced the older DHF/DSS grading with a clinically practical 3-tier classification:
| Category | Definition | Management |
|---|---|---|
| Dengue (without warning signs) | Fever + 2 of: nausea/vomiting, rash, aches, positive tourniquet test, leukopenia | Outpatient management; oral fluids; daily FBC; return if warning signs |
| Dengue with Warning Signs | Dengue + any: abdominal pain, persistent vomiting, fluid accumulation, mucosal bleed, lethargy, liver >2cm, platelet <100,000 | Hospital admission; IV fluid if needed; haematocrit monitoring every 4–6h |
| Severe Dengue | Plasma leakage leading to shock/ARDS; severe bleeding; severe organ impairment | ICU; aggressive fluid resuscitation; blood products; organ support |
Dengue & Blood Transfusion Services
Dengue outbreaks severely stress blood transfusion services. During major outbreaks, demand for platelet transfusions surges — often inappropriately, as platelets recover spontaneously and transfusion is only indicated for significant active bleeding. This creates supply shortages and donor recruitment challenges. Blood donors with dengue symptoms must be deferred; viremic (pre-symptomatic) donors can contaminate the blood supply.
In major dengue-endemic countries (Philippines, Brazil, Bangladesh, India), dengue season predictably overwhelms blood banks. Leukocyte-depleted blood products may reduce risk of dengue transmission through transfusion, but data are limited. PROCALCITONIN and NS1 antigen testing of donated blood units has been proposed but is not standard.
Dengue Surveillance Systems
- WHO DengueNet: Global database for dengue case reporting; 100+ countries contribute data
- Integrated Disease Surveillance: Most endemic countries have national dengue surveillance systems with weekly case reporting by health facility
- Sentinel surveillance: Hospital-based dengue sentinel sites with laboratory confirmation provide more reliable severity data than passive reporting
- Vector surveillance: Breteau index (number of positive containers per 100 houses), stegomyia indices (House Index, Container Index) used to monitor Aedes aegypti infestation and guide vector control timing
- Genomic surveillance: Viral sequencing tracks circulating serotypes and genotypes; predicts outbreak risk in populations with existing immunity to other serotypes. DENV-3 re-emergence after decades of low circulation helped predict the 2022–2024 Americas surge.
- Climate-based early warning: WHO DENGUE research initiatives integrate El Niño/La Niña forecasts with dengue surveillance to provide 3–6 month advance warning of high-transmission years
Related Diseases
Serotypes & Antibody-Dependent Enhancement
Four dengue serotypes (DENV-1, -2, -3, -4) share ~65–70% genomic identity. Infection with any one serotype induces long-lasting (likely lifelong) serotype-specific immunity. However, cross-reactive antibodies from a primary infection can paradoxically enhance uptake of a heterologous serotype into Fc receptor-bearing cells (monocytes, macrophages) without neutralizing it — a phenomenon called antibody-dependent enhancement (ADE). ADE increases viral replication and has been proposed as the primary mechanism driving dengue hemorrhagic fever (DHF) in secondary infections. This complex immunology has made dengue vaccine development particularly challenging — a vaccine must induce protection against all four serotypes simultaneously to avoid creating an immunologically primed-but-unprotected state for unvaccinated serotypes.
DENV-2 secondary infection (after a DENV-1 primary) historically carries the highest DHF risk. DENV-3 has caused severe secondary-infection outbreaks in Latin America and South Asia after years of absence allowed non-immune cohorts to build up. DENV-3 re-emergence contributed to Brazil's record 2023–2024 outbreaks.
Special Populations
Pregnancy
Dengue in pregnancy is associated with higher maternal mortality, preterm labor, low birth weight, and perinatal transmission risk. Vertical transmission (mother to fetus/newborn) is documented — neonatal dengue can be severe. Pregnant women with dengue should be managed as dengue with warning signs regardless of clinical severity.
Infants & Children
Children are the primary victims of dengue mortality globally. Severe dengue (DHF/DSS) is disproportionately common in pediatric patients with secondary dengue infection. Children may not report abdominal pain clearly — altered consciousness, sudden behaviour change, or cold extremities in a febrile child in endemic areas should prompt urgent assessment.
Elderly
Dengue in the elderly carries higher CFR due to comorbidities (cardiovascular disease, diabetes, renal disease). Fluid management must be more conservative to avoid pulmonary edema.
Dengue with Underlying Conditions
Patients on warfarin, aspirin, or other antiplatelets/anticoagulants are at higher bleeding risk. Diabetics may have altered temperature responses. Those with CKD require careful fluid management. Dengue can precipitate sickle cell crises in patients with sickle cell disease.
Dengue Economics & Health Systems Impact
The economic burden of dengue is enormous. Direct costs include hospitalization (~60–80% of costs), outpatient care, and diagnosis. Indirect costs include lost productivity — dengue primarily affects working-age adults and school-age children. A comprehensive analysis in the Lancet (Shepard et al.) estimated the global dengue burden at approximately $8.9 billion annually.
In heavily endemic countries, dengue is one of the top causes of pediatric hospitalization and ICU admission. During dengue surge seasons, health systems in countries like the Philippines, Bangladesh, Vietnam, and India can be overwhelmed — with some hospitals setting up outdoor dengue wards. The impact of dengue on blood supply is significant: thrombocytopenic dengue patients sometimes receive inappropriate platelet transfusions, straining blood banks.
Vector Control: Current Approaches
- Source reduction: Eliminating standing water breeding sites — the most cost-effective long-term strategy. Community engagement and education are essential.
- Larviciding: Biological (Bacillus thuringiensis israelensis, Bti) or chemical larvicides applied to water storage containers and other breeding sites that cannot be eliminated
- Adult mosquito control: Indoor and outdoor ultra-low volume (ULV) insecticide spraying; largely reactive (deployed during outbreaks) and less cost-effective than source reduction
- Wolbachia: Mass releases of Wolbachia-infected Aedes aegypti in Yogyakarta, Indonesia showed 77% dengue case reduction (NEJM, 2021). Deployments ongoing in 13+ countries including Brazil, Vietnam, Australia, Sri Lanka, Mexico, Colombia
- Sterile insect technique (SIT): Release of sterile male Aedes aegypti; reduces wild mosquito population; being trialed in several countries
- Genetically modified mosquitoes (OX513A, Oxitec): Self-limiting male mosquitoes whose offspring die before reaching adulthood; trials in Malaysia, Brazil, Cayman Islands showed mosquito population reduction
Research Frontiers
- Tetravalent vaccine candidates: Additional to Dengvaxia and Qdenga, several candidates are in Phase 1/2 trials: TV003/TV005 (NIAID live attenuated) — strong immunogenicity data in Phase 3 trials in Brazil and Southeast Asia
- Antivirals: No approved dengue antiviral exists. Celgosivir (alpha-glucosidase inhibitor), balapiravir, and NITD008 have failed in clinical trials. Novel targets under investigation: NS5 methyltransferase/RNA-dependent RNA polymerase, NS3 helicase/protease, DENV capsid protein
- Monoclonal antibodies: Broadly neutralizing dengue antibodies (5J7, 2D22) targeting the envelope dimer epitope (EDE) protect against all four serotypes in animal models; early clinical development
- Wolbachia scale-up: World Mosquito Program aims to cover 75 million people in endemic regions by 2025 through Wolbachia deployments
Key Terms: Dengue
- DENV: Dengue virus — four serotypes (DENV-1, -2, -3, -4) each causing equivalent dengue disease but with cross-reactive non-protective immunity between serotypes
- ADE: Antibody-Dependent Enhancement — the mechanism by which cross-reactive (but non-neutralizing) antibodies from a prior dengue infection enhance uptake of a different serotype into Fc receptor-bearing cells, increasing risk of severe disease in secondary infections
- NS1 antigen: Non-structural protein 1 of dengue virus — detectable in blood from days 1-5 of illness; target of rapid diagnostic NS1 antigen tests used in endemic settings
- Aedes aegypti: The primary dengue vector — a highly urban, container-breeding, daytime-biting mosquito; breeds in small water-holding containers around human habitations; found in tropical/subtropical regions globally
- DHF: Dengue Hemorrhagic Fever — the severe form of dengue characterized by plasma leakage, thrombocytopenia, and hemorrhagic manifestations; re-classified as "severe dengue" in WHO 2009 guidelines
- DSS: Dengue Shock Syndrome — severe dengue with circulatory failure due to massive plasma leakage; requires immediate aggressive IV fluid resuscitation; fatal without treatment
- Wolbachia: A naturally occurring intracellular bacterium used in biocontrol — Aedes aegypti infected with Wolbachia have reduced dengue (and chikungunya/Zika) transmission capacity; mass release programs show 77% case reduction in Indonesia
- Dengvaxia: The first licensed dengue vaccine (Sanofi Pasteur); recommended only for individuals with prior dengue infection; risk of severe disease if given to dengue-naive individuals (caused the Philippines 2017 controversy)
- Qdenga: Second dengue vaccine (Takeda); does not require pre-vaccination serology; EU-approved for ages 4-60; effective in both seropositive and seronegative individuals (higher efficacy in seropositive)
- Tourniquet test: A clinical test for dengue: a blood pressure cuff inflated to between systolic and diastolic pressure for 5 minutes; positive if ≥10 petechiae (red dots) per square centimeter appear — indicates increased capillary fragility
More Dengue Questions
Epidemiology at a Glance: Dengue
| Region | Burden | Notes |
|---|---|---|
| South and Southeast Asia | India: ~200M at risk; dengue is #1 arboviral disease. Southeast Asia: 400M at risk across 11 countries | India reported 2.8M cases officially in 2023; true burden estimated 20-50× higher |
| Americas | >6M cases in 2023 (PAHO record); Brazil alone: >4M cases in 2024 H1 | DENV-3 reemergence in 2022 contributed to record 2023–2024 Americas outbreaks |
| Africa | Historically underreported; growing recognition of dengue burden in sub-Saharan Africa | Limited diagnostic capacity; expanding Aedes aegypti range with climate change |
| Pacific Islands | Frequent outbreaks — Samoa, Fiji, Solomon Islands, Micronesia — high population impact in small nations | DENV-2 and DENV-3 causing recurrent waves; very high seroprevalence in adults |
| Europe | Local autochthonous cases in France, Italy, Spain, Croatia via Aedes albopictus | Climate change expanding vector range; small but growing dengue burden in southern Europe |
| Global total (WHO) | 400M infections estimated annually; 100M symptomatic; 40,000 deaths | A 30-fold increase in global dengue over past 50 years; will continue rising with climate change |
Dengue — What Patients Need to Know
- Take paracetamol ONLY for fever — Never take aspirin, ibuprofen (Advil/Nurofen), naproxen, or any other NSAID during dengue illness. NSAIDs increase bleeding risk by inhibiting platelet function.
- Drink lots of fluids: Aim for 5+ glasses of fluid per day (water, ORS, coconut water, fresh juice without sugar). Adequate hydration prevents dangerous hemoconcentration.
- Know the warning signs — go to hospital immediately if: Abdominal pain; persistent vomiting; bleeding (from gums, nose, under skin — petechiae); feeling faint or confused; very cold hands/feet; fever that disappears but you feel WORSE.
- Monitor daily: Get a full blood count (FBC) daily during the illness — watch for falling platelets and rising haematocrit.
- Rest: Avoid strenuous activity. Dengue causes significant immunological and physiological strain — rest supports recovery.
- Do NOT donate blood during or within 28 days of dengue illness — you may be viremic and could infect recipients.
- Vector control at home: Drain ALL standing water around your home weekly — flower pots, buckets, gutters, bottle caps. An Aedes aegypti can breed in as little as 1 teaspoon of water.
- Protect others: If you have dengue, prevent mosquito bites to avoid infecting local Aedes mosquitoes and spreading the virus (use repellent, bed nets, stay in screened rooms).
Dengue: The Big Picture Questions
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Dengue Outbreak Response Protocols
Outbreak response integrates epidemiological surveillance with vector control and clinical management surge capacity:
- Threshold triggers: Most dengue-endemic countries activate emergency response when reported cases exceed 2× the seasonal average for a given week
- Vector control surge: Emergency fogging (space spraying with pyrethroids) reduces adult mosquito populations rapidly, though effects last only days; combined with larval source reduction for sustained impact
- Hospital surge capacity: Pre-positioning IV fluids, training nursing staff on dengue warning signs, and activating overflow treatment areas in gymnasiums or community centers
- Blood bank preparation: Platelet-rich plasma and whole blood reserves positioned for severe dengue patients requiring transfusion
- Community alert systems: SMS alerts, mobile health applications, and community health worker networks for early warning to populations
Dengvaxia Safety Issue & Lessons
Dengvaxia (Sanofi Pasteur) — the first dengue vaccine approved — caused a major public health crisis in the Philippines (2016–2019). Key facts:
- Dengvaxia is safe and effective in people with prior dengue infection (seropositive)
- In dengue-naive (seronegative) individuals, it paradoxically increases severe dengue risk upon subsequent infection — acting like a "silent primary infection"
- Philippines mass-vaccinated ~800,000 schoolchildren without pre-vaccination serology testing
- Subsequent severe dengue deaths in vaccinated children sparked public panic; vaccination program halted
- The crisis severely damaged vaccine confidence across the Philippines, contributing to measles outbreaks
Lesson applied: WHO and subsequent regulatory approvals for Dengvaxia (US FDA 2019) require pre-vaccination serology confirmation of prior dengue infection. The newer Qdenga vaccine (TAK-003) does not have this restriction and is recommended regardless of serostatus.
Dengue in Non-Endemic Travelers
Dengue is the most common cause of fever in returning travelers from tropical regions. Travelers from non-endemic countries have no prior immunity, making them vulnerable to any serotype. Key considerations:
- Dengue symptoms (sudden high fever, severe headache, eye pain, muscle/joint pain) typically begin 4–10 days after a mosquito bite in an endemic area
- Travelers should inform doctors of travel history — dengue may be misdiagnosed as influenza without that context
- Warning signs requiring emergency care: abdominal pain, persistent vomiting, bleeding, lethargy
- Avoid NSAIDs and aspirin (bleeding risk); use paracetamol only for fever and pain
- Most travelers recover fully without complications with adequate hydration and rest
Additional Frequently Asked Questions
- Can I get dengue more than once?
- Yes. There are 4 dengue serotypes (DENV 1-4). Infection with one serotype provides lifelong immunity to that serotype but only short-term cross-protection against the others. A second infection with a different serotype carries higher risk of severe dengue (DHF/DSS) due to Antibody-Dependent Enhancement (ADE). A third or fourth infection typically produces milder disease as broader immunity develops. This is why people in highly endemic regions can be infected multiple times over their lifetime.
- Why is paracetamol (acetaminophen) required instead of ibuprofen for dengue fever?
- Dengue causes thrombocytopenia (low platelet count) and increases bleeding risk. NSAIDs like ibuprofen, aspirin, and naproxen inhibit platelet function and irritate the stomach lining, significantly increasing the risk of dangerous bleeding — including internal hemorrhage. Paracetamol does not affect platelet function and is safe for dengue-related fever and pain management. This is a critical distinction that can be life-saving: always use paracetamol only for dengue fever.
- What is the Qdenga vaccine and who should get it?
- Qdenga (dengvaxia-507/TAK-003, by Takeda) is a live-attenuated tetravalent dengue vaccine approved in 2022–2023 in Indonesia, Brazil, UK, EU, and other regions. Unlike Dengvaxia, it does not require pre-vaccination serology and is recommended for seropositive and seronegative individuals aged 4–60 years. It is given as 2 doses, 3 months apart. WHO recommends it primarily in high-transmission settings where community seroprevalence exceeds 50%. Ask your travel medicine or primary care provider about availability.
Related: Zika Virus · Chikungunya · Brazil & Dengue · Blog: What Is Dengue Fever?
| Primary source | WHO GHO API |
| Source URL | https://www.who.int/data/gho/data/themes/topics/topic-details/GHO/dengue |
| Update frequency | Hourly fetch; WHO publishes weekly |
| Last checked | June 2025 |
| Limitation | Cases may be underreported. Data reflects official reports only. |