Chikungunya Virus Explained

In the early 1950s, people in southern Tanzania fell ill with a sudden fever and joints so painful that many walked stooped over. The name of the illness, chikungunya, comes from the Kimakonde language of southern Tanzania and, according to the WHO, means "that which bends up." Seven decades later the virus behind it has been found in more than 110 countries, and it is one of the few mosquito-borne infections whose main legacy is not the fever but the months of joint pain that can follow.

Educational content, not medical advice. Talk to your doctor before changing any medication, treatment, or routine. Information here reflects current research but every person's situation differs.

This article explains what chikungunya virus (CHIKV) is at the molecular level, why two mosquito species give it such reach, how it differs from dengue and Zika, what the disease looks like from the first bite to the chronic phase, and where diagnostics, treatment, and vaccines stand as of October 2026. It also covers the evidence behind the common claim that "30 to 40 percent" of patients develop long-term arthritis, because the real range is wider than that and depends heavily on how the studies were done.

What kind of virus is chikungunya?

Chikungunya virus is a positive-sense, single-stranded RNA virus in the genus Alphavirus, family Togaviridae, according to the World Health Organization. "Positive-sense" means the viral RNA can be read directly by the host cell's ribosomes, the same way a cell reads its own messenger RNA. The genome is, in effect, a ready-to-run instruction sheet: once it enters a cell, the cell starts building viral proteins from it without any preliminary copying step.

That puts CHIKV in a different viral family from dengue and Zika, which belong to the Flaviviridae. The difference is more than taxonomy. Alphaviruses and flaviviruses use different replication machinery, bind different cell receptors, and cause different patterns of disease. A diagnostic test built for one will not detect the other, and a vaccine for one gives no protection against the other.

For a broader look at how viruses get into cells and copy themselves, see how viruses work: infection to replication.

The particle and its proteins

The CHIKV particle is enveloped: it wears a membrane of lipid it borrowed from the cell that produced it. Studding that membrane are two glycoproteins, E1 and E2. E2 is the part that attaches to receptors on the surface of human cells. E1 is the fusion protein, which, once the virus has been swallowed into a compartment inside the cell, changes shape and merges the viral envelope with the compartment's membrane so the genome can escape into the cytoplasm.

Inside the cell, the viral RNA is translated into a long precursor that is cut into four non-structural proteins, nsP1 through nsP4. Together they form the replication complex, the viral machinery that copies the genome. Later in the cycle the cell also produces the structural proteins that package new genomes into new particles. A useful analogy is a pop-up factory: the first thing the virus builds is the assembly line (nsP1 to nsP4), and only after the line is running does it start turning out finished product.

Why the E1 protein keeps appearing in the story

Mutations in E1 turn out to matter for the mosquito side of the story. The next section returns to this, but the short version is that small changes in this one protein altered which mosquito species could carry the virus efficiently. That is a rare example of single amino acid substitutions changing the geography of an epidemic.

Two mosquitoes, one virus: why Aedes albopictus matters

Like dengue and Zika, chikungunya is spread by Aedes mosquitoes. WHO notes that infected females of both Aedes aegypti and Aedes albopictus transmit the virus, that they bite mainly in daylight, and that the same species can carry dengue and Zika.

The practical difference lies in what each species tolerates. Ae. aegypti is a tropical, urban specialist. It breeds in small containers of standing water close to homes and feeds heavily on people. Ae. albopictus, the Asian tiger mosquito, is more cold-hardy and more flexible about habitat and has spread into temperate parts of Europe, North America, and East Asia. Dengue depends mostly on aegypti. Chikungunya can use both, which is the main reason it can turn up in places dengue struggles to reach.

The mutation that opened the door

A published review of chikungunya's global spread by Weaver and colleagues describes adaptive mutations in the E1 glycoprotein that allowed Indian Ocean lineage strains to use Ae. albopictus as well as Ae. aegypti (Weaver et al., PMC). The best-known of these is a change at position 226 of E1 (alanine to valine, written A226V), and the review's outbreak table notes that Indian Ocean lineage strains carried valine at that position. Those strains drove the epidemic that struck La Réunion and neighboring islands starting in 2005, and the same review lists an estimated 300,000 cases on La Réunion alone.

Think of the virus as a key and each mosquito species as a lock. Before the mutation, the key turned smoothly in aegypti and only stiffly in albopictus. After it, both locks opened. Because albopictus is the species that lives in more temperate regions, the epidemic potential of the virus grew along with the range of that mosquito.

Europe's mosquito map is moving

According to the European Centre for Disease Prevention and Control (ECDC), Ae. albopictus is now established in 16 European countries and 369 regions, up from 114 regions a decade earlier (ECDC, World Mosquito Day 2025). Warmer temperatures extend the months in which mosquitoes are active and shorten the time the virus needs to mature inside them, so a changing climate expands the area where an imported case can seed local transmission. For the wider science behind that trend, see climate change science: how it actually works.

Feature	Aedes aegypti	Aedes albopictus
Common name	Yellow fever mosquito	Asian tiger mosquito
Typical habitat	Tropical and subtropical cities	Tropical to temperate regions, including parts of Europe
Biting time	Mainly daytime	Mainly daytime
Role in chikungunya	Vector; suspected vector in the 1952–1953 Tanzanian outbreak	Vector; principal vector in La Réunion and the 2007 Italian outbreak

Sources: WHO chikungunya fact sheet (April 2025); Weaver et al.; ECDC; Bonilauri et al.

A short history of outbreaks, from 1952 to 2025

Chikungunya was first identified in Tanzania in 1952, and WHO records urban outbreaks in Thailand in 1967 and India in the 1970s. The review by Weaver and colleagues lists the 1952 to 1953 Tanzanian outbreak with an estimated incidence of about 23 percent among the people studied, driven by Ae. aegypti. For roughly five decades after that, the virus caused sporadic outbreaks in Africa and Asia that rarely attracted attention outside those regions.

The picture changed in the 2000s and 2010s. The table below collects the events that matter most, with the source for each figure.

Period	Place	What happened	Source
1952–1953	Tanzania	First recognized outbreak; estimated 23% incidence	Weaver et al.
2005–2006	La Réunion and Indian Ocean islands	About 300,000 estimated cases on La Réunion; E1 mutations let the virus use albopictus	Weaver et al.
2007	Ravenna Province, Italy	First documented outbreak in Europe; 214 laboratory-confirmed cases by December 2007	Eurosurveillance
2013	Saint Martin, Caribbean	First local transmission documented in the Americas	Weaver et al.
2023	Americas	410,754 cases and 419 deaths reported in 17 countries and territories	PAHO
2025	Europe	27 outbreaks by August, a record; first locally acquired case in France's Alsace region	ECDC

Italy 2007: a tropical virus in the Po Valley

In mid-July 2007, residents of two villages in Ravenna Province, Castiglione di Ravenna and Castiglione di Cervia, began seeking care for fever and joint pain. By the end of August about 150 people were ill, and the Italian national health institute confirmed chikungunya in early September, as described in a letter in Emerging Infectious Diseases. Mosquito testing found virus in pools of female Ae. albopictus, and the other species tested were negative.

By mid-December, health authorities had counted 214 laboratory-confirmed cases with symptom onset between July 15 and September 28, 2007, of which 161 were in the two index villages (Eurosurveillance). The outbreak mattered because it showed that a tropical virus could sustain local transmission in a temperate country, using a mosquito that was already living there.

The Americas, 2013 onward

The virus reached the Western Hemisphere in 2013, with local transmission documented on Saint Martin. Within a year it had spread across the Caribbean and into Central and South America. Since then it has not left.

The Pan American Health Organization (PAHO) reported 410,754 chikungunya cases, including 419 deaths, in 17 countries and territories of the Americas in 2023, up from 273,841 cases and 87 deaths in 2022. Its April 2024 update counted 186,274 cases and 60 deaths through epidemiological week 14 of 2024, with about 97 percent of those cases (180,600) in Brazil (PAHO, April 2024). Those are reported figures. Surveillance in many countries misses mild cases and confuses chikungunya with dengue, so the true burden is almost certainly higher.

Europe, 2025

The 2025 season set a continental record for the number of outbreaks. By August, ECDC counted 27 chikungunya outbreaks in Europe that year, including the first locally acquired case in France's Alsace region, which ECDC called an exceptional occurrence at that latitude. Globally, ECDC recorded more than 240,000 cases and 90 deaths in 2025 by the time of its August update. ECDC's weekly surveillance page publishes the current season's counts for France and Italy.

What the disease looks like

Incubation and onset

WHO gives the typical incubation period as 4 to 8 days after a bite, with a range of 2 to 12 days. Illness often starts abruptly with high fever and, in most patients, intense joint pain. WHO adds that without significant joint pain the illness is usually mild, which is one reason mild infections go unrecognized.

The joint pain is polyarthralgia, meaning pain in many joints at once. It typically hits the small joints of the hands, wrists, ankles, and feet, though knees, shoulders, and the spine are often involved. Patients describe stiffness that is worst in the morning and swelling in the affected joints. The stooped, guarded posture that gave the disease its name is a direct consequence.

How common is each symptom?

A 2024 systematic review and meta-analysis in PLOS Neglected Tropical Diseases by Rama and colleagues pooled studies of symptomatic adults with confirmed infection (Rama et al., PMC). Its pooled estimates for the acute phase were:

Acute-phase feature	Pooled proportion	95% confidence interval
Joint pain (arthralgia)	89.7%	82.7–94.0%
Fever	87.8%	84.9–90.2%
Rash	44.3%	35.0–53.9%

The confidence intervals are wide because the studies pooled were very different from one another (the authors report heterogeneity above 90 percent for most outcomes). Read the numbers as "most patients have fever and joint pain, and roughly four in ten have a rash," not as precise constants.

Other common symptoms include headache, muscle pain, nausea, and fatigue. WHO notes that rare eye, heart, and neurological complications have been reported.

Severity and who is at risk

Most people recover fully. WHO states that severe disease and death are rare and mostly affect newborns and older adults with other health conditions. The same meta-analysis estimated mortality of about 0.32 percent in lower-risk groups, and much higher figures in studies of high-risk groups, with very wide uncertainty. Those high-risk estimates come from a small number of studies and should be treated cautiously.

Hemorrhagic complications, the hallmark of severe dengue, are not a typical feature of chikungunya. That distinction matters in practice, because it affects which painkillers are safe, as the treatment section explains below.

The chronic phase: why joint pain can outlast the virus

The feature that sets chikungunya apart from most mosquito-borne infections is not the acute fever. It is the joint pain that continues after the virus has been cleared from the blood. WHO says the pain may last days, weeks, months, or years.

How many patients that applies to depends on how you count. The Rama meta-analysis pooled studies of the general population, including children and people with other conditions, and found chronic symptoms in 43.8 percent of patients at 3 months, 34.3 percent at 6 months, and 31.8 percent at 12 months. The confidence intervals were wide (for example, 21.5 to 44.3 percent at 12 months) and heterogeneity was around 96 to 97 percent, which tells you that individual studies disagreed substantially.

Other analyses give different numbers, and published estimates overall span a very large range. The differences are driven by:

• How long patients were followed.
• Whether cases were laboratory-confirmed.
• Whether the outcome was self-reported pain or a clinician-confirmed arthritis.
• Which population was studied, including age and whether participants had prior joint disease.

So when you see "30 to 40 percent develop chronic arthritis," treat it as a reasonable one-year ballpark from pooled data rather than a fixed property of the virus. At a year, roughly a third of patients in the Rama analysis still had symptoms, and the fraction is higher at earlier time points and lower later.

Why does the pain persist?

The mechanism is not fully settled. Several explanations are under study, and they are not mutually exclusive. One idea is that viral RNA or protein lingers in joint tissue and keeps the local immune response switched on. Another is that the inflammation triggered during the acute infection becomes self-sustaining, in the way a smoldering fire in a wall can keep burning after the visible flames are out. A third is that the infection unmasks or accelerates an underlying joint condition. Which of these dominates probably differs from patient to patient, which is one reason treatment of chronic disease remains hard. For background on how the body mounts these responses, see how the human immune system fights viruses, step by step.

Chikungunya vs. dengue vs. Zika

The three viruses share vectors, overlapping geography, and early symptoms. They differ in what they tend to do to patients.

Feature	Chikungunya	Dengue	Zika
Virus family	Togaviridae (Alphavirus)	Flaviviridae	Flaviviridae
Main vectors	Ae. aegypti, Ae. albopictus	Mainly Ae. aegypti	Ae. aegypti, Ae. albopictus
Fever	Abrupt, often high	High	Low-grade or absent
Joint pain	Severe, hallmark feature	Mild to moderate	Mild
Rash	Common	Common	Common, often early
Bleeding complications	Uncommon	Yes, in severe dengue	Rare
Long-term consequence	Persistent joint pain in a substantial minority	Post-infection fatigue in some	Congenital abnormalities after infection in pregnancy
Licensed vaccine	Yes, see below	Yes	No

For detail on the flavivirus side of this comparison, see dengue virus explained and Zika virus explained. A third mosquito-borne flavivirus with a very different ecology, spread between birds and mosquitoes, is covered in West Nile virus explained.

Why dengue and chikungunya are easy to confuse

Both can start with fever, headache, muscle and joint pain, and rash, and both circulate in the same cities. Joint pain that is severe and prominent, plus the absence of bleeding signs, leans toward chikungunya, but that is a clinical hunch and not a diagnosis. The distinction has real stakes. WHO and the CDC both advise against NSAIDs such as ibuprofen until dengue has been ruled out because of bleeding risk, and the CDC also names aspirin. Patients and clinicians who guess wrong in either direction can cause harm, which is why laboratory confirmation is the standard.

How chikungunya is diagnosed

According to WHO, RT-PCR can detect viral RNA in blood during the first week of illness. After the first week, antibody tests are used, and antibodies remain detectable for about two months. In plain terms, the early test looks for the virus itself, and the later test looks for the immune system's footprints.

Method	What it detects	Best window	Notes
RT-PCR	Viral RNA	First week of illness	Most sensitive early; confirms active infection
Antibody tests (serology)	Immune response to the virus	After the first week	Antibodies stay detectable for about two months, per WHO

Timing is the practical constraint. A PCR test taken too late can miss the virus, and an antibody test taken too early can miss the response, so the date of symptom onset matters as much as the test chosen.

Treatment: supportive care only

There is no specific antiviral drug for chikungunya. The CDC states that no medicines are available to treat the infection and that rest, fluids, and over-the-counter pain relievers can ease symptoms. WHO recommends paracetamol (acetaminophen) for fever and pain until dengue is ruled out, because NSAIDs can increase bleeding risk.

That is the baseline for acute illness. Beyond it, clinicians manage persistent joint pain case by case. Physiotherapy to preserve movement, anti-inflammatory medication when it is safe, and in some patients longer-term immune-modulating drugs are all used in practice, but the evidence base is thinner than it is for the acute phase. Because every patient's situation differs, that is a conversation for a treating physician, not something a general explainer can settle.

Research into antivirals is active, including drugs aimed at the E1 fusion step and at the nsP2 protease, an enzyme the virus needs to cut its precursor into working proteins. None had reached approval at the time of writing.

Vaccines: a short history of two products

For decades no chikungunya vaccine existed. Two now have regulatory approval in some countries, and WHO says they are not yet widely available and that it is reviewing data to inform possible recommendations. Their stories in the United States have gone very differently.

Vaccine	Developer	Type	US approval	Age group	Status in the US
Ixchiq	Valneva	Live-attenuated (weakened virus), single dose	November 9, 2023 (accelerated approval)	18 and older	License suspended in August 2025
Vimkunya	Bavarian Nordic	Virus-like particle (no genetic material from the virus), single dose	February 14, 2025	12 and older	Licensed

Sources: FDA, November 2023; Bavarian Nordic press release via BioSpace; AABB, August 2025.

Ixchiq: the first licensed vaccine

On November 9, 2023, the FDA approved Ixchiq as the first chikungunya vaccine, for adults 18 and older at increased risk of exposure. It is a live, weakened virus given as one intramuscular injection. The approval was accelerated, meaning it rested on immune response data rather than confirmed clinical benefit, and the FDA required follow-up studies. In North American safety trials of about 3,500 participants, severe chikungunya-like reactions occurred in 1.6 percent of vaccine recipients and in none of the placebo recipients, according to the FDA's announcement.

Because it contains weakened live virus, it can cause symptoms that resemble the disease, which is the central trade-off of this vaccine design. A live vaccine tends to produce a strong, lasting immune response, but it carries a risk of replicating in people whose immune systems cannot control even a weakened virus.

What happened in 2025

Earlier in 2025 the FDA paused use of Ixchiq in people over 60 while it investigated reports of serious adverse events, then lifted the pause after labeling changes. In late August 2025 the agency went further and suspended the vaccine's license. As reported by AABB, the FDA cited more than 20 serious adverse events, including a death from encephalitis, and noted that the vaccine's clinical benefit had not yet been confirmed in follow-up studies. Valneva stopped shipping and selling the vaccine in the United States.

This is a good example of how accelerated approval is meant to work and where it can fail: the first approval was conditional, post-marketing safety monitoring surfaced problems, and the regulator acted. It does not say anything about the other vaccine, which uses a different technology.

Vimkunya: a virus-like particle

Vimkunya, from Bavarian Nordic, was approved by the FDA on February 14, 2025, for people 12 and older. It is a virus-like particle (VLP) vaccine. VLPs are assemblies of the virus's outer proteins that mimic the look of the real virus but contain no viral genome, so they cannot infect cells, replicate, or cause disease. The company reported that two phase 3 trials enrolled more than 3,500 healthy people 12 and older, and that neutralizing antibodies appeared in up to 97.8 percent of recipients 21 days after a single dose.

Neutralizing antibodies are a measure of immune response, not proof of protection in the field, which is why post-marketing studies matter. The safest summary is that Vimkunya is a non-live alternative whose longer-term real-world performance is still being established.

For how vaccines train the immune system generally, including the difference between live and non-replicating designs, see how vaccines actually work.

Prevention: where the mosquito is the target

Since a vaccine is not yet a routine option for most people, prevention remains mainly about avoiding bites and reducing mosquito breeding. WHO's list for individuals and communities includes:

• Avoiding mosquito bites, especially during the first week of illness, so infected people do not pass the virus to mosquitoes (the CDC makes the same point).
• Emptying and cleaning containers that hold water every week, since Aedes breed in small pools around homes.
• Using insecticides during outbreaks.
• Wearing covering clothing, using window and door screens, and applying repellents containing DEET, IR3535, or icaridin.
• Using insecticide-treated nets for people who sleep during the day.

An unusual feature of these mosquitoes is that they bite in daytime, so a bed net at night, the classic tool against malaria, does little for most exposure. The advice therefore centers on clothing, repellents, screens, and removing standing water.

People wonder why some individuals seem to attract more bites. That is its own area of research, summarized in why mosquitoes bite some people more.

Why chikungunya matters for global health

Several forces explain why a disease that was once a regional curiosity has become a recurring global concern.

1. Vector range expansion. Ae. albopictus now lives across much of southern and central Europe, and ECDC's figures show how fast its map has changed.
2. Chronic disease burden. If roughly a third of patients still have symptoms a year later, each large outbreak leaves a long tail of lost work and disability that does not appear in death statistics.
3. Diagnostic confusion with dengue. In places where both circulate, misdiagnosis leads to wrong treatment advice and inaccurate surveillance.
4. Vaccine uncertainty. The 2025 suspension of the first licensed vaccine shows how much remains to be learned about safety in older adults and in people with underlying conditions.
5. Travel and urbanization. An infected traveler arriving in a region where Aedes mosquitoes already live can start a local cluster, as the Italian 2007 outbreak and recent French clusters showed. Fast-growing cities with water storage and poor drainage supply breeding sites. For how diseases cross from animals and between regions in general, see how viruses jump from animals to humans.

Common misunderstandings

"It's just a tropical disease." The 2007 Italian outbreak and the recent European outbreaks, including France's in 2025, show that where an albopictus population exists, an imported case can lead to local spread. The risk is seasonal and geographically patchy, not zero.

"It's the same as dengue." The two share vectors and early symptoms, but they are unrelated viruses. Treatment advice differs in one important way, the avoidance of NSAIDs until dengue is ruled out.

"Recovery means the virus is gone and the pain will stop." In many people it does, but a substantial minority has joint symptoms for months. How long they last is highly variable.

"A vaccine solves it." Vaccines are an additional tool. They are not yet widely available, one US-licensed product was suspended, and WHO is still reviewing the evidence for recommendations.

"Mosquito nets are enough." Nets help against night-biting mosquitoes. Aedes bites during the day, so source reduction and personal protection matter more.

The takeaway

Chikungunya is best understood as a disease with two phases, an acute fever that most people clear within about a week or two and a joint-pain phase that a sizeable fraction of patients carry for months. The virus's reach comes down to a mosquito and a mutation: the E1 change that let the Indian Ocean lineage use Ae. albopictus helped carry the disease into temperate countries, and a warming climate is extending that mosquito's range. The tools are still limited. There is no antiviral, diagnosis depends on timing, and vaccine options in the United States narrowed in 2025 when the first licensed product was suspended. What stays constant is the most mundane advice in public health: reduce standing water, avoid daytime bites, and get a laboratory-confirmed diagnosis before treating a fever and joint pain as dengue or chikungunya.

Frequently Asked Questions

Q: Is chikungunya the same as dengue? A: No. Chikungunya is an alphavirus in the family Togaviridae, and dengue is a flavivirus in the family Flaviviridae. Early symptoms overlap, but chikungunya typically causes more prominent and longer-lasting joint pain, and bleeding complications are not typical. Both are spread by Aedes mosquitoes, so laboratory testing is needed to tell them apart.

Q: How long does chikungunya joint pain last? A: It varies widely. WHO says joint pain may last days, weeks, months, or years. A 2024 meta-analysis found chronic symptoms in about 44 percent of patients at 3 months and about 32 percent at 12 months, though the studies disagreed substantially, so individual outcomes cannot be predicted from these averages.

Q: Can chikungunya be fatal? A: Rarely. WHO says severe disease and deaths are rare and mostly affect newborns and older adults with other health conditions. In 2023, PAHO reported 419 deaths among 410,754 reported cases in the Americas, which is about 0.1 percent of reported cases, though under-reporting of mild cases makes any fatality ratio uncertain.

Q: What made the 2007 outbreak in Italy significant? A: It was the first documented chikungunya outbreak in Europe. A traveler-introduced virus spread locally through Aedes albopictus, and 214 laboratory-confirmed cases were counted by December 2007. It showed that tropical viruses can circulate in temperate countries that host this mosquito.

Q: How is chikungunya diagnosed? A: Per WHO, RT-PCR detects viral RNA in blood in the first week of illness, and antibody tests are used after the first week, with antibodies detectable for about two months. Because symptoms resemble dengue and Zika, laboratory confirmation is the standard approach where several viruses circulate.

Q: Is there a vaccine for chikungunya? A: Two vaccines have regulatory approval in some countries. In the United States, the FDA approved Ixchiq in November 2023 and Vimkunya in February 2025. The FDA suspended Ixchiq's license in August 2025 after serious adverse event reports, leaving Vimkunya, a non-live virus-like particle vaccine licensed for people 12 and older. WHO says neither is yet widely available.

Q: Why does Aedes albopictus matter for chikungunya spread? A: Both Aedes aegypti and Aedes albopictus can transmit the virus, but albopictus tolerates cooler climates and is established in 16 European countries, according to ECDC. Mutations in the E1 protein let the Indian Ocean lineage use albopictus efficiently, which is why the virus can spread in places where dengue cannot easily become established.

Q: What is the best way to prevent chikungunya? A: WHO recommends avoiding mosquito bites with covering clothing, screens, and repellents containing DEET, IR3535, or icaridin, and emptying containers that hold water every week. Because the mosquitoes bite in daytime, bed nets help mainly people who sleep during the day. Vaccination may be an option for some travelers; a doctor can advise on eligibility.

Sources

• World Health Organization. Chikungunya fact sheet (dated April 14, 2025).
• Centers for Disease Control and Prevention. About Chikungunya Virus.
• Pan American Health Organization. Epidemiological Update: Chikungunya in the Region of the Americas, April 22, 2024.
• European Centre for Disease Prevention and Control. World Mosquito Day 2025: Europe sets new records for mosquito-borne diseases and weekly chikungunya surveillance.
• Weaver SC, et al. Arrival of Chikungunya Virus in the New World: Prospects for Spread and Impact on Public Health. PLOS Neglected Tropical Diseases, 2014.
• Rama K, et al. Clinical outcomes of chikungunya: a systematic literature review and meta-analysis. PLOS Neglected Tropical Diseases, 2024.
• Bonilauri P, et al. Chikungunya virus in Aedes albopictus, Italy. Emerging Infectious Diseases 2008;14(5):852–854.
• Eurosurveillance. Autochthonous chikungunya virus transmission may have occurred in Bologna, Italy, during the summer 2007 outbreak, 2008;13(3).
• US Food and Drug Administration. FDA approves first vaccine to prevent disease caused by chikungunya virus, November 2023.
• Bavarian Nordic. FDA approval of chikungunya vaccine for persons aged 12 and older, February 14, 2025.
• AABB. FDA suspends BLA for chikungunya vaccine, August 28, 2025.

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