Researchers Discover Chikungunya Vaccine Safe and Effective in Phase 3 Trial

The mosquito-borne illness chikungunya has periodic, unpredictably occurring epidemics. For the last 15 years, more than 5 million cases of the chikungunya virus have been reported, highlighting it as a threat to global health.

Chikungunya virus infections have been found in more than 100 countries globally due to rising international travel and the expansion of possible vectors.4, 5 Chikungunya virus illness symptoms can affect people of all sexes and ages and can include the quick onset of a fever, viremia, acute joint pain, recurrent mild joint discomfort, and maculopapular rash. These symptoms often present 4–7 days after infection. 

The initial phase 3 trial of the vaccine for chikungunya demonstrated that it was safe and elicited an effective immune system response to combat the viral illness. The Lancet published this study. However, because the study was not carried out in areas where chikungunya is widespread, the researchers could not determine whether the VLA1553, a vaccine created by French biotech company Valneva, offers protection against subsequent illness. 

Neither vaccinations nor antiviral medications are currently approved to treat or prevent the illness brought on by CHIKV infection. “This could become the first chikungunya vaccine accessible to individuals living in endemic areas, in addition to for travelers to areas where it is endemic or areas at risk for an impending outbreak,” said primary research author Martina Schneider, Clinical Strategy Manager at Valneva. 

“Our encouraging results demonstrated strong antibody level persistence following vaccination, which is significant given that chikungunya epidemics may rebound suddenly. In a release, Schneider said that age is a risk factor for the severity and death of chikungunya, so the high immune response shown in older participants may be especially advantageous.  

According to research author Katrin Dubischar, Programme Director of Chikungunya Vaccination at Valneva, there is no specific treatment or vaccination for chikungunya. Additionally, research has revealed that global warming is causing the mosquitoes that spread the virus to expand into new parts of the world. It is now thought to be one of the infectious agents that is most probable to spread globally. Consequently, having an effective vaccination is crucial for being ready for such outbreaks in the future, according to Publisher. 

In over 43 research locations in the US, 4,115 healthy participants were enrolled in the study. 3,082 subjects received one injection of VLA1553 in the arm, while 1,033 received a placebo. Although the immunological response was only examined in an isolated group of 362 participants (266 of whom received the vaccination and 96 a placebo), everyone was considered in the safety analysis. 

Following immunization, the immunological responses of the participants were evaluated one week, 28 days, three months, and six months later. For 11 days following immunization, they also kept an electronic diary of side effects. 99 percent (263/266) of subjects had antibody levels deemed protective against illness following a single dose of VLA1553. According to the researchers, there was no variation in immune response based on age. 

They also accept that giving children a chikungunya vaccine will be necessary if endemic sickness is to be effectively controlled. Teenagers in endemic regions of Brazil are the subject of a study that is now being conducted to ascertain safety and efficacy in this age range. 

According to Kathryn Stephenson of the Beth Israel Deaconess Medical Center’s Centre for Virology and Vaccine Research, “the positive results of this trial are excellent news for CHIKV pandemic preparedness.” Stephenson, who was not involved in the study, stated that “CHIKV and other arboviral infections continue to be global threats, spurred on by the expansion of mosquito habitats due to climate change and the globalization of trade and travel.” 

Real-world effectiveness studies in the setting of actual CHIKV outbreaks, as well as additional trials of VLA1553 in endemic regions and enlarged populations, such as a current study in adolescents in Brazil, will be crucial in confirming VLA1553’s utility for CHIKV prevention. Stephenson continued.