Body + Brain

18
Aug

Chikungunya Vaccine Passes Critical Trial, but Is Still Years Away

For years, mosquito-borne virus chikungunya has been hopscotching around the globe, infecting one virgin population after another, inflicting the infected with fever and debilitating pain that can last for months. Now, after sweeping the Caribbean, the disease is settling into the U.S.’s Gulf Coast region, raising concerns that it’s one mutation away from a push farther north.

But there’s some good news on the horizon. For years, NIH scientists have been working on a vaccine for chikungunya, and a study published last week in the journal Lancet reports that the shot has passed a critical phase 1 clinical trial. Twenty-five adult volunteers participated, and none were adversely affected by the vaccine.

Aedes albopictus
Aedes albopictus, better known as the Asian tiger mosquito, is a known carrier of chikungunya.

Will Dunham, reporting for Reuters:

The volunteers were not exposed to the chikungunya virus, but their immune response was measured in the form of neutralizing antibodies – proteins produced by a special type of white blood cell that defends a person from an invading virus.

An immune response was seen in most of the volunteers after the first vaccination. Following the second, all exhibited high levels of antibodies. There also was a significant increase in antibodies after the third injection.

The antibodies lasted a long time and were present in all of the volunteers six months following their final shot.

Phase 1 trials are just the beginning of a long road toward clinical use. Phase 2 and 3 trials add additional participants and continue to evaluate the safety and effectiveness of the vaccine. Trial sizes vary depending on the treatment; they are determined based on how many participants are needed to be statistically confident in the results.

Most vaccines take decades to move from development to clinical use, but, based on these early results, NIH researchers are confident that the chikungunya vaccine will be ready far sooner. It does not use weakened or dead virus particles, instead relying on particles that mimic the virus, an approach also used in the human papillomavirus vaccine.