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Topline
A vaccine against chikungunya – a mosquito-borne infection with symptoms similar to dengue and Zika – may finally be on the horizon after promising results from a late-stage trial in the Lancet Monday, a key to tackling the emerging global health threat as climate change creates increasingly ideal conditions for the virus to spread explosively, including in the United States
Aedes mosquitoes can spread chikungunya.
Highlights
Valneva’s chikungunya vaccine, made from a weakened form of the virus and given as a single dose, was safe, well tolerated and elicited an immune response that indicates protection against the disease, according to the clinical trial by advanced stage of the company published in the peer-reviewed medical journal.
The researchers said the trial – which recruited 4,115 healthy adults across the United States, of whom 3,082 received the vaccine – did not raise any safety concerns about the vaccine and Juan Carlos Jaramillo, physician chief of Valneva, said an independent committee evaluating the trial data and all adverse events reported subsequently came to the same conclusion.
Common side effects reported in the trial included headache, fatigue, muscle and joint pain and pain at the injection site, which were consistent across different age groups.
Because the study was conducted in the United States, a region where chikungunya is not endemic, the researchers measured the immune system response to test whether the vaccine protects against diseases caused by infection with the virus.
Immune responses – tested on 362 participants, 266 of whom received the vaccine – were strong, the researchers said, with 99% showing levels of antibodies considered protective against the virus 28 days after vaccination.
While antibody levels – which were similar for younger and older subjects – dropped after day 28, researchers said protection persisted for 96% of vaccinees six months after being vaccinated.
Large number
$500 million. This is the estimated global market for chikungunya vaccines by 2032, according to Valneva.
To monitor
The length of the trial meant the researchers were unable to assess the protection offered by the vaccine for periods longer than six months and they said a follow-up study was already underway to test the immune responses over five years. They said the results from one year are encouraging. As a precaution, researchers are also monitoring the risk of miscarriage after the vaccine, which is slightly higher in research subjects than in the general population. Although this may be due to small sample size and be a natural statistical variation – two miscarriages were explained by a genetic disorder or medical history while no reason could be identified for the other – and no safety issues have been reported, the researchers said monitoring will be needed as the vaccine is rolled out.
What we don’t know
As the study was undertaken in the United States, protection against chikungunya was inferred from the immune response elicited by the vaccine. While antibody levels are predictive of protection against serious illness – antibodies are proteins that can block viruses from entering cells – they are only one aspect of the immune system and have a relatively long lifespan. short and offer only a partial glimpse of the potential value of a vaccine. Studies in areas where chikungunya is endemic – naturally spreading and constantly present – will be needed to verify and expand the results of the trial and see how it works in the real world. Important factors considered by researchers are its impact on children and adolescents – a trial is underway in Brazil – and whether existing or subsequent exposure to the virus will significantly alter responses to the vaccine. Writing in a linked commentary post, Kathryn Stephenson, a researcher at the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center who was not involved in the study, said that “real-world efficacy studies in the context of actual outbreaks” also be crucial in confirming the value of the shot.
Key Context
The name chikungunya come of the Kimakonde language, meaning “to contort” or “that which bends”, a reference to the hunched or twisted posture of people infected with the virus due to the severe joint pain it can cause. In addition to joint pain – potentially debilitating and which can last for weeks, months or even years and develop into chronic arthritis – symptoms of chikungunya include fatigue, headaches and nausea and the infection is often mistaken for dengue and Zika, which have similar symptom profiles. Although serious illness and death from chikungunya is rare – children and the elderly are most at risk – the virus can still cause significant health problems in areas where it circulates, Aslam Khan, assistant clinical professor at pediatric infectious diseases and a member of the global health faculty at Stanford University, said Forbes. There is also no treatment directly targeting the virus and no approved vaccine. Valneva, which was until recently in competition for primacy with Merck, is potentially in line to be first and its shot is under review by the Food and Drug Administration and Canada’s health authority.
Peg News
Chikungunya is transmitted by Aedes mosquitoes, which are usually found in warmer tropical regions of the world and are responsible for the spread of other viruses, including dengue, Zika and yellow fever. There have been several epidemics of chikungunya in various parts of the world this year, including parts of the Americas and Asia. Various health authorities and experts have identified it as a emerging threat to global health.
crucial quote
khan said Forbes he considers the risk to the United States from chikungunya to be low, but said he believes “that is changing.” Khan explained that we “have already found the mosquito vector in the United States and with climate change, there may finally be favorable conditions for the continued growth and proliferation of these species. Humans can serve as a potential reservoir for the virus that can be picked up and spread by these mosquitoes,” he explained.
Further reading
Floods, heat and other climate hazards turn 218 infectious diseases into bigger threats, study finds (NBC News)
The history of the chikungunya virus (Lancet)
Disease X: the 100-day mission to end pandemics (Book by Kate Kelland)
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Sources 2/ https://www.forbes.com/sites/roberthart/2023/06/12/first-vaccine-for-chikungunya-an-emerging-mosquito-borne-threat-nears-after-promising-trial-results/ The mention sources can contact us to remove/changing this article |
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