A prototype Swiss vaccine aiming to prevent blood pressure has shown encouraging results. The study among a small group of volunteers was published in Saturday's Lancet.

The trial formula aims at priming antibodies -- the front line in the body's immune system -- against angiotensin II, a protein hormone notorious for causing blood vessels to constrict and thus raise blood pressure.

Drugs already exist which successfully tackle angiotensin II hypertension.

But these can also have side effects and patients may be haphazard about taking them regularly.

The vaccine was tested among a small group of 72 patients with mild-to-moderate blood-pressure problems, which was split into three subgroups.

Two of the subgroups received the vaccine in lower or higher doses, and the third was given a dummy formula, or placebo.

The main point of this trial was to assess the vaccine for safety, and adverse effects seen among the volunteers were deemed to be either minor or unrelated to the vaccine.

As for effectiveness, the vaccine favourably tackled a surge in early-morning blood pressure, which is when most strokes and heart attacks occur.

The vaccine, called AngQb, was tested by its maker, Swiss pharmaceuticals firm Cytos Biotechnology AG, although the results were assessed independently.

To gain a license, the vaccine will have to undergo two far larger trials to assess it for safety and efficacy.

In a commentary also published by The Lancet, Swedish doctors Ola Samuelsson and Hans Herlitz said the results were "intriguing and promising."