According to the Lancet, (an esteemed British medical journal) the high blood pressure vaccine has just gone through stage II of it’s testing, and so far so good.

There were some sore arms and “flu like” symptoms after the shot, and a few people had problems that were listed as “adverse reactions” but probably were not related to the vaccine.

The vaccine produced antibodies against Angiotensin II enzyme, one of the enzymes in the renin angiotensin system of the kidney that let you retain fluid to prevent dehydration. We docs already have pills to “block” the angiotensin I enzyme (e.g. enalapril, lisinopril) and angiotensin II enzyme (e.g. losartan), so the vaccine essentially works by destroying the enzymes as if they were a germ.

The bad news: the vaccine in the article didn’t work very long so they had to give two booster shots to keep the blood pressure down,and even then the “halflife” was only 17 weeks (i.e. it lasted for four to five months).

But the Blood pressure fell nicely, lowering 9/4 points in the low dose group to 25/13 in the higher dose vaccine.

That isn’t enough for severe high blood pressure, but it is about as good as taking one pill. (People with very high blood pressure might have to take two or three pills a day, in very bad cases even more than that).

The high blood pressure shot discussed in the Lancet article (“CYT006-AngQb—a vaccine based on a virus-like particle—that targets angiotensin II to reduce ambulatory blood pressure.”) uses IgG antibodies that are fooled into recognizing the Angiotensin II enzyme as a germ, and so the body will make antibodies against it.
There’s another vaccine being tested that uses a slightly different method of doing this that is earlier in the testing phase. (“Angiotensin Therapeutic Vaccine (ATV) is a conjugate of a 12-amino acid analogue of angiotensin I (PMD3117) crosslinked to keyhole limpet hemocyanin (KLH).”)

The vaccines work against the Renin Angiotensin system of the kidney, which instructs the kidney to excrete fluid and making the blood vessels squeeze partly closed to keep your blood pressure at normal levels. It is something that keeps you from dying of dehydration when you are hot, and makes your blood pressure go up if you bleed from a big wound. But when you have kidney disease, or for unknown reasons, sometimes it overdoes a good thing and you have high blood pressure.

When we docs treat blood pressure, we use medicines that work in various ways, from relaxing the blood vessels so they don’t spasm to “water pills” which get rid of the extra fluid. But the best medicines are the “ACE inhibitors” which work against Angiotensin I (e.g. enalapril) and Angiotensin II (e.g. Losartan) by blocking them.

Presumably, the shot would act like these pills by destroying the enzyme.

What are the long term effects? That is a big question, but in a world where lots of people forget to take lots of their pills, the “side effect” of missing a pill may be a major stroke or heart attack.

The shot, if it has only a few side effects and could be made cheap, could also be a life saver for people in poor countries.

Here in Asia, high blood pressure is a major killer. This might be due to the diet: soy sauce and fish sauce and all sorts of salty dishes.

But blood pressure pills cost money. One common pill here costs 7 pesos a day (20 cents): not much, but too much when a lot of people earn only 2 dollars a day.  Needless to say, a lot of people die because they don’t buy medicine because they can’t afford it.

Another link about the vaccines is this USATODAY article from a couple months ago.

Finally, the vaccine is only at Stage II, which means it will be a few years more before it is released, and that assumes that there won’t be problems that stop it being released.

But the hope is eventually people will just get a shot every couple of months instead of trying to remember to take their pills each day.


Nancy Reyes is a retired physician living in the rural Philippines. Her website is Finest kind Clinic and Fishmarket, and she writes medical essays at HeyDoc Xanga blog.

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