Researchers have tested a vaccine, S100A9, that may be able to replace oral blood thinners to reduce the risk of secondary strokes caused by blood clots, without increasing the risk of serious bleeding or triggering an autoimmune response, according to a new research.

Oral blood thinners are medicines that help blood flow smoothly through your veins and arteries. According to the study, people who have had a stroke caused by a blood clot often need to take medications that make their blood less likely to clot, which helps prevent another stroke.

"Many stroke patients do not take their blood thinning drugs as prescribed, which makes it more likely they will have another stroke. This vaccine might one day help solve this issue since it would only need to be injected periodically," said Hironori Nakagami, Professor at Osaka University in Japan.

The findings, published in the journal Hypertension, revealed that the vaccine prevents blood clot formation and protected the arteries of treated mice from forming new clots for more than two months. The vaccine in mice provided protection against blood clots for more than two months without increasing the risk of bleeding or causing an autoimmune response. 

In addition, it worked as well as the clopidogrel (oral blood thinner) in a major artery. Developing a vaccine to replace and/or complement daily, oral medications might save many lives and help prevent both secondary strokes and possibly heart attacks, according to Nakagami. "...there are differences between mice and humans in how the vaccine will be recognized by the immune system. We should be able to overcome such problems and believe this vaccine provides a very promising strategy in secondary prevention of stroke," he noted.