The US Food and Drug Administration said Thursday that it has approved the first vaccine to prevent disease caused by the chikungunya virus.
The single-dose vaccine, Ixchiq, made by Valneva Austria GmbH, is approved for adults who are at an increased risk of exposure to the virus. Ixchiq was granted fast track and breakthrough therapy designations.
Chikungunya, a mosquito-borne disease whose name in the Makonde dialect of Africa means “bending over in pain,” has no specific treatment and can be debilitating and even deadly for newborns. Health experts consider it to be an emerging threat to global health made worse by climate change, with at least 5 million cases in the past 15 years, although deaths and severe illness are rare, according to the World Health Organization.
People most at risk of infection live in Africa, Southeast Asia and parts of the Americas, where chikungunya-carrying mosquitoes are endemic, but the climate crisis has driven the virus to new parts of the world.
Before 2006, the virus was rarely identified even in US travelers, the US Centers for Disease Control and Prevention says, but studies identified a couple dozen cases in the US travelers between 2006 and 2013. In late 2014, cases that stemmed from local transmission were reported in warmer parts of the US: Florida, Texas, Puerto Rico and the US Virgin Islands.
People who get sick with chikungunya typically have a fever and can develop joint pain. They may also have a headache, muscle pain and a rash. For some, the joint pain can be debilitating, and it can last years. About 20% to 30% of cases are expected to become chronic, research shows. For newborns, chikungunya can be a potentially deadly threat.
Ixchiq contains a live, weakened version of the virus, so it may cause symptoms that are similar to an infection.
The FDA said that in one study, the vaccine virus was detected in people’s blood in the first few weeks after they were vaccinated. The prescribing information that comes with the vaccine carries a warning to make sure health care providers tell their patients that it is not known whether the vaccine virus can be transmitted from a pregnant person to their newborn, and it is not clear whether the vaccine virus can hurt a newborn. The warning tells providers to weigh the threat of the virus to the patient, as well as the gestational age and risks to the fetus or neonate from the disease.
Because there’s no specific treatment for chikungunya, doctors typically tell patients to rest, drink lots of fluids and take over-the-counter medication to manage their fever or pain. But scientists say that a vaccine is the best option for people vulnerable to the virus.
“Infection with chikungunya virus can lead to severe disease and prolonged health problems, particularly for older adults and individuals with underlying medical conditions,” said Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, in a statement from the agency. “Today’s approval addresses an unmet medical need and is an important advancement in the prevention of a potentially debilitating disease with limited treatment options.”
The FDA is requiring that vaccine maker Valneva do a postmarket study to make sure there are no serious risks to the vaccine.
The most common side effects reported in studies submitted to the FDA for the vaccine’s approval included headache, muscle and joint pain, fever, tenderness at the injection site and being tired. Nearly 2% of people who got the vaccine had severe chikungunya-like adverse reactions that required medical intervention. Only two of the nearly 3,500 people in the trials had to go to a hospital because of the reaction. Some also had a chikungunya-like adverse reaction that lasted at least 30 days. The vaccine comes with a warning to encourage providers to discuss any potential reactions a patient may have to the vaccine.