A US Army vaccine may help fight an outbreak of the chikungunya virus

Imagine getting a bee sting every 10 minutes. How would you feel? That’s what the US Army, hospital workers and scientists have been able to do with a seemingly innocuous insect that ticks off a pregnant woman in three weeks. (Afterward, its saliva may contribute to pregnancy complications.) The bee sting feels great and leaves no lasting negative consequences, but it also exposes the woman to a treatable virus that can lead to birth defects and potentially fatal complications.

That virus is chikungunya (also known as a fever, joint pain and rash virus) and this week a US medical center in Long Island received a new kind of vaccine to protect against it. While the vaccine for chikungunya has only been available to users for several years, it’s not the only promising remedy in the race to curb the virus.

The virus is spread to humans by mosquito bites. It’s an RNA virus, so it creates fewer copies of itself each time its body is exposed to the virus. So its replication rate is remarkably low (even with multiple mosquitoes carrying it), and as a result, it doesn’t infect as many people as its similar cousins. That means it’s relatively easy to halt the virus’s spread and help eradicate it from the world’s most populous cities: Toronto, Miami, San Francisco and even Seoul, South Korea.

However, the virus has become increasingly common and severe in countries such as Central and South America and the Caribbean. The World Health Organization now acknowledges that chikungunya might be a “major global health threat.”

Doctors and researchers are spending more and more time and effort figuring out how to figure out a way to stop this virus from spreading and bringing about the birth defects that the virus can cause.

Their latest findings might help us avoid an epidemic of a disease that could cause irreversible birth defects if it hits the US.

A researcher is developing a vaccine against chikungunya by knocking off some of the virus’ genes. That will lower the body’s replication of the virus and “create a series of genetic weapons against the virus”, says Vincent Cannata, a epidemiologist with the US Army’s Materiel Command at Fort Belvoir in Virginia.

On Tuesday, an advisory panel for the Food and Drug Administration voted that the scientists’ recommendation of the research should be approved. Here’s what Cannata and his colleagues had to say about the vaccine’s effectiveness against the disease.

The vaccine performed well against samples of the virus, which was able to persist outside the body for two months (about double the expected duration).

The study examined four doses of the vaccine at three months and also test dose factors. Three doses of the vaccine were effective at both time intervals, but Cannata was surprised to find that four doses were also well-tolerated by volunteers.

The vaccine was approved by the Food and Drug Administration in 2015 for vaccines against dengue, another mosquito-borne virus, and chikungunya. A trial of the vaccine was about to begin in Port-au-Prince when Hurricane Matthew hit the Caribbean island nation in October 2016. No one was injured and nothing was destroyed, but the researchers had to stop the testing.

The epidemic-resistant virus, which Cannata developed with the goal of finding a permanent cure for chikungunya, could be effective as soon as 2019, he told the FDA’s medical advisory panel.

Although the vaccine has “higher efficacy than the current antiviral medication against chikungunya, the size of the population (mostly infected with the disease during its more widespread pandemic), the broad prevalence (activity in all regions of the US from Florida to Canada) and lack of immediate demonstrated transmission suggest that vaccination of a relatively small number of at-risk persons … may be needed to pre-empt an epidemic,” the panel said.

Cannata’s vaccine will be tested over a period of about six months. If it proves effective and safe, the first company in the US to bring it to market would have rights to sell it to US health care institutions, and US Customs and Border Protection would then have to approve the vaccine for importation into the US.

While you can protect yourself from chikungunya by keeping your windows and doors closed during peak hours when mosquitoes are most active (9:00 a.m. to 3:00 p.m. ET), the CDC recommends that pregnant women get the oral form of the vaccine. As long as you’re expecting, you must take the shot.

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