Report links HPV with heart attacks, strokes - underlying mechanism unclear.

[mzmolly]

NEW YORK (Reuters Health) - A new study shows heart attacks and strokes are more common in women infected with human papillomavirus, or HPV.

The research only included a small number of women with heart disease, and it doesn't prove that the sexually transmitted infection is to blame. In fact, it's still unknown whether the women already had the virus before they suffered heart attacks and strokes.

Previous studies have suggested an increased risk of heart disease in people with certain infections, including HIV, hepatitis C and one strain of Chlamydia -- but also haven't been able to prove cause-and-effect.

"It is unclear what is the underlying mechanism for such risk, though the infection itself, (the) body's reaction to infection or a general milieu of inflammation may account for a part of the risk," said Dr. Adeel Butt, from the University of Pittsburgh School of Medicine, in an email to Reuters Health. He was not involved in the new work.

http://www.reuters.com/article/2011/10/26/us-hpv-idUSTRE79P7LE20111026

If "(the) body's reaction to infection or a general milieu of inflammation may account for a part of the risk" - might the HPV vaccine increase risk as well?

I hope to see further research in this regard.

[sharp_stick]

1. The vaccine

does not cause an increase in inflammation or a response indicative of an infection. An infection response is on a much more massive scale than any vaccine response especially when looking at recombinant vaccines like Gardasil. In addition the vaccine response, no matter how strong is fleeting and does not recur.

This study is very small, far too small to draw any conclusions from. When the overall infection rate among all women is as high as HPV is in the US right now it makes it very difficult to infer any kind of correlation between HPV and heart attacks and stroke.

on edit: To actually carry out a more definitive study would be a pretty massive undertaking. They would likely need to follow thousands of women over a number of years.

[mzmolly]

2. The vaccine doesn't cause inflammation or an

immune response?

[sharp_stick]

3. It causes an immune response

but not an infective response which is much broader in scope and intensity.

The immune response is directed against specific haptens and antigens not the entire virus and especially not against an infection consisting of billions of actively replicating viral particles.

Inflammation, as described in the paper, is not found in vaccinations with recombinant particles.

[mzmolly]

4. I'm sorry, but your response appears to contradict the article.

"It is unclear what is the underlying mechanism for such risk, though the infection itself, (the) body's reaction to infection or a general milieu of inflammation may account for a part of the risk,"

Vaccines are meant to stimulate a like reaction to an infection. So, presumably an immune response to HPV is potentially at issue. I suppose it could be argued that an inflammatory response to a vaccine vs X disease/virus etc. is less robust?

"Inflammation, as described in the paper, is not found in vaccinations with recombinant particles."

What do you mean by "inflammation as described by the article"?

Edited for grammar.

[sharp_stick]

5. It's more or less a matter of degree of response

Apologies in advance, this is kind of long winded. The short answer is found at the end if you'd like to skip the rest.

An immune response in response to a vaccine is similar to the infection in that it produces an initial response. It's different from an infection in that the response is limited to a small quantity of individual protein pieces (capsid protein in this case) of the virus that have been produced recombinantly so no virus is involved at all.

These pieces are selected because they produce a really specific and reproducible immune response but they can't reproduce or infect cells like the intact virion can.

The vaccine produces an initial response from the immune system B-cells teaching them, for lack of a better term, to recognize these capsid proteins. There are three doses of the vaccine because each time the body sees the protein it produces a faster response to the protein. The first response to these capsid proteins or an infection takes time to set up and subsequent exposures take less time. By the time the third dose is given the bodies immune system is fully primed. When the person is then exposed to the virus later in life the body is ready for it and produces a strong antibody response getting rid of it before the virus can set up shop in the cells it likes to hide in.

The unvaccinated bodies reaction to an infection is, at an early point, the same as the vaccine but not as directed. The actual virus contains other proteins and DNA, in addition the virus has plenty of time to infect cells and reproduce before the immune system takes it out. When enough viral particles exist inside the infected cells they break open the cell and escape to do it again. Eventually your body produces an immune response to this infection and fights it off. Unfortunately viruses like HPV hide out in cells that aren't all that well screened by the immune system so every now and then there is another breakout infection causing warts etc. That's why it doesn't go away after the first infection.

Now to get to the answer to your questions. It's different from an infection because the vaccine can't reproduce and it's to a single protein the response is short and directed to only a single cell type (B-cells) it's not the same as an infection where the response of the body is to multiple proteins and the debris from dead cells caused by replicating virus particles. Inflammation caused by viruses like HPV is mostly due to the remains of the cells bursting open to release virus particles. It's a non-directed response to debris and protein in the system.

I took a look at the paper and they raise some interesting questions. Unfortunately their data set was small and that doesn't allow them to really come up with a definitive conclusion.

[mzmolly]

6. I thank you for taking the time to respond.

As I mentioned above, one could argue a lesser immune response would have a lesser impact, regardless of any potential connection. It seems this is what you're arguing, in greater detail.

We appear to disagree that a vaccine could have a potential, like impact, if an immune response is involved in any connection.

That said, we appear to agree that more studies would be prudent.

Peace :hi: