What is HPV?
Dr. Thorning: HPV stands for human papilloma virus, a virus that slowly infects. There are over 200 known strains. They are the same virus in other strains that cause external genital warts and other more rare skin infections. A few of them are highly — as we’ve come to call it — the cancer gene.
If there are 200 strains, how common is it?
Dr. Thorning: It depends on who you ask. The HPV is thought by some to be virtually in all of us, part of our normal flora. But the right strain in the right location, with the right stimulant can produce external warts, genital warts, or changes can lead to cancer. Not all people with cervical infections, even with high-risk types, get cancer, but 99.7 with cancer have this high-risk DNA and high-risk HPV.
How many cervical cancers are caused by HPV?
Dr. Thorning: It’s an epidemiologic association. However, that association has been said to be stronger than the association of smoking for lung cancer. In fact, 99.7 percent of cervical cancer tissues, when sampled, have high-risk HPV DNA in them.
How many strains cause cervical cancer?
Dr. Thorning: There have been six strains and are all designated by number as they were found. There are two predominant strains, type 16 and type 18, which account for over 70 percent.
What vaccine is being used?
Dr. Thorning: Again, it’s those two types, type 16 and type 18, that are used. Type 16 is nearly 50-percent responsible for all cervical cancers that have been sampled, and then type 18 is the other 20 percent to 23 percent.
How effective is the vaccine?
Dr. Thorning: Thus far the vaccine is extremely effective and may lead to the largest breakthrough in our career as health care providers. The preliminary trial, which looks at this particular vaccine product in a smaller population, shows the prevention with persistent infection that seems to be the pathology leading to cancer chains, not transient infection that comes and goes.
If you’re sampling women, doing PAP smears, and looking for DNA in a timely enough basis, what we’ve found is various types of the virus come and go. This as been a sort of unintended consequence of the trial, we’re getting perfected information about how humans and risk VD types interact. Types seem to come and go, but with, again, high-risk types, that can lead to cancerous changes, and the vaccine in the previous trial has shown it to be nearly 100-percent effective, which for a vaccine is extremely exciting.
Do you have any way to compare that to a vaccine we’ve seen in the past?
Dr. Thorning: I think the best comparison I have, because I’m working on this, too, is the Herpes vaccine that the NIH, for example, got involved with because it’s a very exciting result. It is shown to be 75 percent effectatious, which is a little bit more real from a general statement. One hundred percent is … we don’t see that.
How deadly is cervical cancer?
Dr. Thorning: Cervical cancer is quite deadly. In the United States, a relatively small number of women die from their cervical cancer relative to the number that have PAP smears taken. In the developing world, where public health is not present, a high percentage of individuals who get cervical cancer die. This is the primary push behind finalizing the vaccine, its use in developing countries.
Will governments in the developing world pay for a preventative vaccine like this?
Dr. Thorning: That’s the reason for the test case with the Hepatitis vaccine. The introduction of the Hepatitis B vaccine 20 years ago has eliminated 95 percent to 99 percent of the disease, depending on the survey.
How many people are needed for the trial?
Dr. Thorning: In this trial we’re looking for 18,000 patients worldwide. We already have 15,000 people enrolled.
So when could this be on the market?
Dr. Thorning: That’s up to pharmaceutical companies. Certainly within five years, optimistically within three years.
Who would get the vaccine and what would the established protocol be?
Dr. Thorning: The vaccine being study is a prophylactic vaccine, which is a preventative for infection. We are doing some research to examine the effect of the vaccine as a therapeutic vaccine for individuals already infected with HPV, however, the greater results we’re seeing is in the ability to prevent infection. The population we would vaccinate would be those with no interaction with the virus, or those not at risk for acquisition of the virus. This includes pre-sexual females or preadolescent, the younger the better would be my recommendation.
What are the side effects?
Dr. Thorning: We’ve seen local side effects that are the only statistical significance in the trial. There are some local reactions; the DLT tends to cause a local immune response. There is also some pain, redness and swelling with the injection. The systemic side effects, such as fatigue, headache, and nausea, have not been shown to be any more prevalent than the placebo, so hopefully it won’t be a significant amount of systemic adverse reactions.
What do you do to the cervix to see changes?
Dr. Thorning: If they’re early changes they’re followed. There is a whole gradation system that is published when the virus is detected. If there are changes in the cervix, the doctor will do a PAP smear quicker than they would otherwise. If the PAP smear is negative, maybe six months to a year, if it’s positive, the next test will be done in about two months to six months. Certainly, if there are cellular changes that are thought to be precancerous, those cells are dealt with immediately.
What puts someone at risk for getting the HPV infection?
Dr. Thorning: Being sexually active is really the only way to get the infection. We are not sure how men are transmitting though.
How would a man know he was a carrier of the virus?
Dr. Thorning: He could have genital warts and also there are some dangerous cancers of the anal that can be caused by the HPV virus. Another sign of the virus are skin cancers.
If a woman has an abnormal PAP smear, does that mean she is infected with HPV?
Dr. Thorning: It means they could’ve been, usually the predominant, 85 percent of all abnormal PAP smears are what’s called abnormal.
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If you would like more information, please contact:
Lisa Taulbee
Research Director
Westover Heights Clinic
2330 N.W. Flanders St. Suite 207
Portland, OR 97210
(503) 226-6678
[email protected]
http://www.westoverheights.com
