In a global first, some travelers and laboratory researchers who are at risk of contracting chikungunya will soon be allowed to be vaccinated against the virus.
A committee of vaccine experts recommended Wednesday that those selective groups of people should be offered access to the new vaccine, Ixchiq, which is made by Valneva Austria GmbH. It will become U.S. vaccination policy when Mandy Cohen, director of the Centers for Disease Control and Prevention, signs off on the recommendation from the Advisory Group on Immunization Practices.
Chikungunya is a mosquito-borne virus that is not endemic in the United States. The U.S. records about 100 to 200 cases of chikungunya a year, in people infected abroad. The virus, which is spread mainly by Aedes aegypti and Aedes albopictus mosquitoes, is mainly found in parts of Central and South America, Africa and Asia.
The condition is rarely fatal. But the virus can cause a nasty infection involving fever and joint pain. While most symptoms typically clear up in about a week, the joint pain can be severe and persistent, sometimes lasting months after infection. Babies infected around the time of birth, adults 65 and older and people with heart disease, diabetes or high blood pressure are at higher risk of severe disease.
The ACIP recommended that researchers who work with chikungunya viruses and people traveling to places with an ongoing chikungunya outbreak should be allowed to be vaccinated. The committee also said that some people traveling to places where the virus is known to have spread over the past five years should be able to get vaccinated, in consultation with a health care provider. They include people 65 and older with underlying health conditions who are likely to have at least moderate exposure to mosquitoes, and people who will be staying in such a setting for six months or more.
The vaccine cannot be given to children. It was licensed last fall by the Food and Drug Administration for people 18 years of age and older.
While the groups of people eligible for the vaccine in this country will likely be very limited initially, the CDC indicated it may later consider recommending the vaccine for people living in U.S. territories where chikungunya virus may spread.
While the disease is unpleasant, getting the vaccine can also be uncomfortable. It is a live-virus vaccine, containing chikungunya virus that was weakened in a lab. Live-virus vaccines can be what’s known as reactogenic, making people feel temporarily unwell.
In the studies done to support licensure of the vaccine, 11.7% of participants who got the vaccine reported adverse reactions, compared to 0.6% of people who got a placebo shot. And 1.6% of vaccine recipients reported reactions severe enough to prevent them from taking part in daily activities or to require medical care. None of the participants in the placebo arm reported severe reactions.