select search filters
briefings
roundups & rapid reactions
Fiona fox's blog
Scientists comment on cases of Chikungunya virus in China.
Prof Roger Hewson, Virus Surveillance Lead, Genomic Surveillance Unit at the Wellcome Sanger Institute, said:
“A significant outbreak of chikungunya virus (CHIKV) is currently ongoing in Guangdong province, China, with over 8,000 confirmed cases reported in recent weeks. This represents the largest documented outbreak of CHIKV in China and has prompted aggressive containment measures, including quarantines, drone-based fogging and legal enforcement of mosquito control efforts. CHIKV is a mosquito-borne virus that usually causes acute, self-limiting illness but can also lead to prolonged joint pain and, in some cases, severe complications such as neurological or ocular involvement.
How concerning is the current CHIKV situation in China?
“The outbreak in Foshan and surrounding areas of Guangdong province has unfolded rapidly and at a scale unprecedented for China. Authorities have responded with containment strategies reminiscent of COVID-19 measures, including household-level inspections, enforced bed-netting and fines for non-compliance with mosquito control. Unlike previous imported or isolated cases, this outbreak involves sustained local transmission, reflecting both increased environmental suitability for Aedes mosquitoes and a lack of population immunity. The scale and speed of spread mark it as a notable public health event in East Asia.
What are the symptoms, and who is most at risk?
“CHIKV infection typically presents with high fever, intense joint and muscle pain, rash, headache and fatigue. While many recover within a week, joint pain can persist for weeks, months, or even years in some individuals, mimicking conditions like rheumatoid arthritis. Older adults, infants, pregnant individuals and those with underlying health conditions are more likely to experience severe or prolonged illness and a minority may develop neurological or ocular complications. Importantly, many cases are asymptomatic or mild, allowing undetected individuals to contribute to transmission by feeding – infecting mosquitoes.
How is CHIKV spread?
“CHIKV is transmitted via the bites of infected Aedes aegypti and Aedes albopictus mosquitoes, both of which are active during the daytime and breed in small pools of standing water. The virus is not spread directly between people. In this outbreak, Aedes albopictus is likely to be an important driver of transmission (although this is not currently confirmed). This vector has adapted to cooler climates and urban environments, making it a key vector for spread in subtropical regions like Guangdong.
Does CHIKV have pandemic potential?
“Yes. CHIKV is already listed by the WHO and CEPI as a priority pathogen for vaccine development. It has demonstrated an ability to cause explosive outbreaks and is continuing to adapt genetically for more efficient spread by Aedes mosquitoes. With expanding global travel and a warming climate, new regions are becoming suitable for transmission. The current outbreak in southern China highlights how densely populated, previously unaffected areas may become vulnerable. Pandemic potential is amplified by the absence of pre-existing immunity in these populations and the difficulty in rapidly controlling mosquito-borne outbreaks.
What is the risk to the UK and UK travellers?
“At present, the risk of local CHIKV transmission within the UK is considered very low, as the key mosquito vectors are not widely established in the UK. However, the risk to UK travellers visiting southern China is tangible. Travellers should take standard precautions to avoid mosquito bites, including using insect repellents, wearing long sleeves and trousers during the day and staying in screened or air-conditioned accommodation. There are no formal travel restrictions in place, but the outbreak warrants attention from clinicians and public health authorities, particularly in relation to returning travellers with febrile illness.
Is there a vaccine? Should it be used?
“Two CHIKV vaccines have been approved for use in the UK: IXCHIQ and Vimkunya. IXCHIQ is a single-dose live attenuated vaccine approved for immunocompetent adults aged 18 to 59, but its use is currently restricted in those aged 65 and above due to safety concerns raised by the Commission on Human Medicines. Vimkunya, meanwhile, is approved for individuals aged 12 and older. Although not yet in widespread use, these vaccines may be available through specialist travel health services. Several other vaccines, including virus-like particle, mRNA-based and measles-vectored platforms, are under active development. Vaccination is recommended for individuals at higher risk travelling to outbreak areas, particularly older adults, immunocompromised persons and pregnant women, though availability and eligibility criteria should be checked in advance.
“In summary the chikungunya outbreak in China is a timely reminder of the growing risks posed by vector-borne viruses in an era of climate change, global mobility and shifting mosquito ecology. Although the virus is unlikely to spread within the UK under current conditions, travellers to southern China may be exposed and should take appropriate precautions. The recent authorisation of CHIKV vaccines in the UK offers new tools for prevention, particularly for vulnerable individuals. With no antiviral treatments and unpredictable outbreak dynamics, ongoing surveillance, vaccine accessibility, and vector control remain essential to mitigating the threat posed by this increasingly global arbovirus.”
Dr César López-Camacho, Group Leader and Jenner Investigator, at the Jenner Institute, University of Oxford, said:
How serious is this chikungunya outbreak in China? Is it unusual?
“Yes, this is a significant outbreak. With over 7,000 confirmed cases reported in Guangdong Province, this is the largest chikungunya outbreak ever documented in China. Until now, the country had only recorded a few imported cases, with no sustained local transmission. It is likely that CHIKV reported infection increase in the next weeks.
“What makes this event notable is that chikungunya has never been established in mainland China before. This suggests that most of the population had no pre-existing immunity, making it easier for the virus to spread quickly. In general, outbreaks of mosquito-borne viruses tend to occur in populations that are “naive” to the virus, meaning people have not been previously exposed and are not protected.
What are the symptoms, and how dangerous is the virus? Who is most at risk?
“The virus causes: Sudden high fever, severe joint and muscle pain, fatigue, rash, and headaches. Most people recover in a couple of weeks, but some, especially older adults, may suffer from long-lasting joint pain that mimics arthritis. Although chikungunya rarely causes death, it can be extremely uncomfortable and disabling. The most vulnerable include the elderly, newborns, and people with underlying health conditions.
How is it spread?
“Chikungunya is spread by infected Aedes mosquitoes, especially Aedes aegypti and Aedes albopictus. These mosquitoes are active during the day and thrive in warm, wet conditions. The virus does not spread directly between people, but someone infected can pass it to mosquitoes during the first few days of illness, allowing the outbreak to grow.
Could this virus become a pandemic? Is the UK at risk?
“It is extremely unlikely to cause a pandemic in the traditional sense, as chikungunya does not spread from person to person. However, it can cause large regional outbreaks, especially when introduced to mosquito-rich, low-immunity settings, like what we are probably seeing in China.
“In the UK, the risk is currently low. These specific mosquitoes are not widespread here. But we do need to watch closely, as climate change and global travel are expanding the range of these mosquitoes, and with it, the viruses they carry.
“It is also important that genetic sequencing of the virus in this outbreak is carried out. In past outbreaks, mutations have helped chikungunya adapt to new mosquito species. If the virus has changed, we need to ensure current vaccines still offer protection. This can be tested in laboratory studies using sera blood samples from individuals and isolate the main lineage of CHIKV that is currently circulating in Guangdong.
What’s the risk to people in the UK or those travelling to China?
“There is no risk to people living in the UK. However, travellers to southern China, particularly Guangdong Province, should be cautious. The US Centre for Disease Control and Prevention has issued a Level 2 travel alert, recommending travellers use insect repellent, wear long sleeves, and stay in screened or air-conditioned accommodation. Travellers returning from affected areas who develop fever and joint pain should seek medical attention and mention their recent travel.
Can you get vaccinated against chikungunya? Is it recommended?
“Yes. There are now two approved vaccines:
People travelling to high-risk areas may consider vaccination, particularly if they are at higher risk from infection. A travel clinic must advise on eligibility and availability.
https://pmlive.com/pharma_news/mhra-approves-valnevas-chikungunya-vaccine-ixchiq-for-use-in-adults/
Additional comments?
“At the Jenner Institute, University of Oxford a Phase I clinical trial of a chikungunya vaccine in the UK was completed, showing strong protection across all known types of the virus.
“I now lead efforts to develop mRNA vaccines for chikungunya and other mosquito-borne viruses. mRNA technology allows for faster vaccine development and can be adapted to respond to emerging outbreaks. We are actively seeking grant funding and philanthropic support to advance clinical trials in regions where chikungunya is a major public health concern; i.e sub-Saharan Africa, where mosquito-borne viruses are co-endemic and vaccine access is urgently needed.
“The outbreak in China is a clear reminder that when a virus enters a population without existing immunity, outbreaks can escalate rapidly. This highlights the urgent need for vaccines that provide broad, cross-lineage protection, and for ongoing surveillance to track how these viruses evolve. Preparing now is essential to prevent larger, more disruptive epidemics in the future.”
Prof Tom Solomon, Director of The Pandemic Institute, Liverpool, said:
How concerning are these chikungunya figures in China? Is this a significant outbreak?
“Yes, this is a large and significant outbreak of chikungunya virus in China. It represents a major public health concern, especially given the scale and speed of transmission in affected areas.
What are the symptoms of infection and how dangerous is this virus? Are some people more at risk than others?
“Most people infected with chikungunya virus develop a sudden fever, headache, joint pains, and a rash. While the majority recover within a week, a small proportion experience serious complications such as encephalitis (inflammation of the brain). In addition, some individuals develop long-term arthritis that can last for months or even years. The elderly, the very young, and those with underlying health conditions are more vulnerable to severe disease.
How is it spread?
“Chikungunya virus is spread by Aedes mosquitoes; primarily Aedes aegypti and Aedes albopictus. These mosquitoes are common in tropical and subtropical regions, and are now becoming more established in parts of southern Europe.
Does this virus have pandemic potential?
“Chikungunya has the potential to cause large outbreaks across multiple countries. However, because it is not transmitted directly from person to person, it does not pose the same level of pandemic threat as a virus like COVID-19.
What is the current risk to people in the UK or to those travelling from the UK to China?
“There is a theoretical risk that someone infected in China could travel to the UK. However, it is unlikely that the virus would spread further here, as the mosquito species required for transmission are not currently fully established in the UK. That said, with climate change, Aedes mosquitoes are moving northward through Europe, and have sporadically been found in the UK, potentially increasing future risk.
Can you get a vaccine for chikungunya? Is it recommended?
“Vaccines against chikungunya have been developed recently and are now available. However, there have been reports of serious side effects in people over the age of 65. As such, the vaccine is currently recommended for travelers under 65 visiting high-risk areas; these include parts of Asia, Africa, Latin America, and the Caribbean, where Aedes mosquitoes are widespread.”
Prof Will Irving, Emeritus Professor of Virology, University of Nottingham, said:
How concerning are these chikungunya figures in China? Does this appear to be a significant outbreak/ different to other cases?
“Yes, the outbreak is concerning, but I don’t think this is anything new. There have been equally large, if not larger outbreaks around the world prior to this one.
What are the symptoms of infection and how dangerous is this virus? Are some people more at risk than others?
“Abrupt onset of fever, joint and muscle pains, headache, skin rash. Mortality is low (I would estimate well under 1%) – the JCVI use the phrase “Chikungunya is an unpleasant disease which only rarely results in death. However, chronic disability rates can be high”
“As with most infections, outcomes are worse for patients with any kind of immunosuppression, for the very young and the elderly, and patients with underlying co-morbidities.
How is it spread?
“Via the bite of an infected Aedes mosquito
Does this virus have pandemic potential? If so, is this is a risk here?
“Not really – transmission requires the presence of the appropriate mosquito. However, with climate change, the mosquitos are spreading, and there are reports of the mosquito being present in parts of Europe (France, Italy, Spain).
Currently what is the risk to those in the UK/ those travelling to China from the UK?
“The risk for those living in the UK is entirely related to those who travel to endemic areas around the world.
Can you get a vaccine for this? Is it recommended?
“There are vaccines available and approved for use in the UK, but there are potential side effects and care needs to be taken. This link gives the UK JCVI recommendations: https://www.gov.uk/government/publications/chikungunya-vaccine-for-uk-travellers-jcvi-advice-16-july-2025/chikungunya-vaccine-in-uk-travellers-jcvi-advice
Any additional comments?
“As a general comment, although Chikungunya is a nasty disease and there are outbreaks, it pales into significance when compared to dengue, which is transmitted by the same mosquito.”
Dr Robert Jones Assistant Professor, London School of Hygiene & Tropical Medicine (LSHTM), said:
How concerning are these chikungunya figures in China? Does this appear to be a significant outbreak/ different to other cases?
“The frequency of outbreaks of chikungunya has increased since 2000, just as we have seen more outbreaks of dengue and Zika, and there have been more severe forms of the disease. There was an outbreak in La Réunion in 2006, which had an estimated 260,000 cases, and in India during 2005–06 with a reported 1.3 million cases. Then again in 2016, India had a massive outbreak, with over 64,000 cases confirmed across the country. In 2013, the virus was introduced to Saint Martin Island in the Caribbean and over the next three years cases were confirmed in almost 50 countries or territories in the Caribbean, Central America, South America, and North America, with more than 1 million suspected cases. By comparison this outbreak in China is of course small, but I think it is the largest outbreak in mainland China and has already affected the lives of thousands of people. In China, there is a risk of chikungunya spreading to other regions. Southern and eastern provinces, particularly those with warm, humid climates and dense urban development (e.g. Fujian, Guangxi, and Hainan), are at risk of further transmission. There are also international risks associated with this outbreak. The risks of these local outbreaks have increased because of climate change and urban expansion.
What are the symptoms of infection and how dangerous is this virus? Are some people more at risk than others?
“The most common symptoms of chikungunya are fever and joint pain. Other symptoms can include headache, muscle pain, joint swelling, or rash. Some people don’t present any symptoms.
“Although chikungunya is rarely fatal, the illness can be debilitating. In some cases, joint pain may persist for months, a condition known as chronic chikungunya disease.
How is it spread?
“Chikungunya virus is spread by the bite of an infected mosquito, primarily Aedes aegypti and Aedes albopictus. Arboviral infections are often asymptomatic, so people may be infected but not know it. They might not have any symptoms but they can contribute to onward transmission – someone could be carrying the virus, get bitten by a mosquito, and that mosquito could later infect someone who may be more susceptible and have a more severe illness. These mosquitoes thrive close to human habitats – humans provide a blood source, and in domestic environments they can find water tanks and discarded plastic containers that can provide suitable places for their larvae to develop. When small pools of water form, these mosquitoes can lay their eggs and in just 7-10 days adults will emerge. So, following the monsoon or heavy rains, we often see a lot more mosquitoes and this can be followed by a rise in mosquito-borne diseases. The mosquitoes that are able to transmit the chikungunya virus are common in tropical and subtropical parts of the world, including in parts of the Americas and Southern Europe.
Currently what is the risk to those in the UK/ those travelling to China from the UK?
“If people travel to areas where there is an outbreak there is a risk of them being bitten by an infected mosquito, and acquiring the virus. They should take extra precautions. There are currently no antiviral treatments to treat chikungunya. The best way to prevent chikungunya is to protect yourself from mosquito bites – such as using insect repellent, wearing long sleeves and trousers, and staying in accommodations with screened windows or air conditioning. Vaccination is recommended for some travelers.
“There is no risk of contracting chikungunya in the UK at present. The mosquitoes that transmit chikungunya are not established in the UK, although they are found in parts of southern Europe. Occasionally, imported cases are diagnosed in returning travelers, but these do not lead to local transmission.
Can you get a vaccine for this? Is it recommended?
“The chikungunya vaccine (IXCHIQ) can offer protection but comes with precautions: due to rare but potentially serious side effects, its use is currently suspended in people aged 65 years or older.
Declared interests
Prof Tom Solomon:
Member of the Encephalitis Society (a charity focused on encephalitis awareness, support and research) since 1998 and President of the Encephalitis Society since 2019.
Director of The Pandemic Institute (since September 2021), which has received funding from Innova, CSL Seqirus, Aviva and DAM Health (unpaid).
Advisor to the GSK Ebola Vaccine programme in 2015 and the Siemens Diagnostic Programme in 2018 and 2019 (paid).
Part of the Data Safety Monitoring Committee of the GSK Study to Evaluate the Safety and Immunogenicity of a Candidate Ebola Vaccine in Children GSK3390107A (ChAd3 EBO-Z) vaccine (unpaid).
Chaired the Siemens Healthineers Clinical Advisory Board in 2018 and again in 2019 (paid).
Co-Chaired the World Health Organization Covid Neuro Coalition task force in 2020 (unpaid) and sat on the United Kingdom of Great Britain and Northern Ireland Government’s Advisory Committee on Dangerous Pathogens (ACDP) between 2019 and 2023 (unpaid), and the Medicines and Healthcare products Regulatory Agency (MHRA) Expert Working Group on COVID-19 vaccines between 2020 and 2023 (paid).
Advised the United Kingdom COVID-19 Therapeutics Advisory Panel (UK-CTAP) between 2020 and 2021 (unpaid).
Member, COVID-19 Vaccines Benefit Risk Expert Working Group, for the Commission on Human Medicines (CHM) committee of the MHRA between 2020 and 2023 (paid).
Committee Member of the Wellcome Trust Pathogen Biology and Disease Transmission Discovery Advisory Group (paid).
Dr César López-Camacho: As stated in the comment, Dr César López-Camacho is working to develop mRNA vaccines for chikungunya and other mosquito-borne viruses.
Prof Will Irving: No conflicts
Dr Robert Jones: Robert is also employed at Arctech Innovation.
For all other experts, no reply to our request for DOIs was received.