Blood Pressure Vaccine Shows Promise

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For this trial, 72 volunteers with mild to moderate high blood pressure were injected with 100 or 300 micrograms (ug) of the vaccine or a placebo at zero, four and 12 weeks from the start of the trial. Volunteers included 65 men and seven women, average age 51.5 years.

Patients who received either dose of the vaccine produced antibodies against angiotensin II after the first injection. The response was significantly higher in those who received the higher dose and was also relatively longer-lived.

After 14 weeks, systolic blood pressure (the top number in a reading) in the high-dose group was reduced by 5.6 mm Hg and diastolic blood pressure (the bottom number) fell by 2.8 mm Hg.

And there was another, unexpected benefit: The vaccine appeared to dampen the typical blood pressure surge that occurs between 5 a.m. and 8 a.m., lowering systolic blood pressure by 25 mm Hg and diastolic blood pressure by 13 mm Hg in that time period.

The wee hours of the morning are the most dangerous time to have high blood pressure as it raises the risk of heart attack and stroke, experts noted.

The vaccine also produced only a slight increase in renin levels. Renin is an enzyme that is thought to cause inflammation and may play a role in kidney failure.

The vaccine needs further testing, especially to see if the body would be allowed any "escape mechanism" that would allow it to raise blood pressure if and when needed.

And, even with vaccines, the patient has to agree to the treatment. "Even with the safest and most effective vaccines today, compliance is not 100 percent," Jones said.

More information

For more on high blood pressure, head to the American Heart Association.