A vaccine against high blood pressure could be available in four or five years, allowing hypertensive patients can maintain their blood pressure for up to four months without having to take daily medication.

A high blood pressure vaccine is a kind of proteinic antigen, similar to a nerve hormone called angiotensin. Once injected, it prevents angiotensin from constricting blood vessels. When it enters the body, an antibody is created to maintain blood pressure in a relaxed state.

However, this vaccine cannot produce a permanent antibody like anti-epidemic vaccines do. But a single injection of the vaccine will reportedly remain effective for up to five to six months.

The reason such a high blood pressure vaccine is attracting public attention is that many hypertensive patients have problems as they do not faithfully take medicine regularly.

Cho Myung-chan, a professor of internal medicine at Chungbuk National University Hospital, said, "There is a report that only 27 percent of hypertensive patients in the country take medicine regularly as instructed by doctors. This is the primary reason why the treatment of many such patients has failed."

The 2007 National Health and Nutrition Survey also reported that only 38 percent of hypertensive patients aged 30 or older were controlling their high blood pressure properly.

But many problems need to solve before the vaccine is put to practical use. "Patients who take high blood pressure medicine can stop taking the medicine temporarily when their blood pressure goes down due to a sudden rise in temperature," said Lee Sang-hak, a professor of circulatory medicine at Severance Hospital. "But after the vaccination, they can't raise their blood pressure for five or six months even if they want to, so in that case there is the risk of going into shock or becoming dehydrated due to low blood pressure."