Talking to Your Girls: The Best Vaccine of All

In a previous posting, I noted that there are almost no studies looking at whether giving the human papillomavirus (HPV) vaccine to adolescents increases unsafe sexual behavior -- what some call a passport to promiscuity for girls and a license to drill for boys.  Although there are still no studies looking at behavior post-vaccine, the Archives of Pediatric and Adolescent Medicine just published a study on the attitudes and beliefs of girls who got the HPV shot.
The authors asked the girls (ages 13-21) to agree or disagree with statements like, "After getting the shot against HPV, I am less worried about getting a sexually transmitted disease other than HPV," and "After getting the shot against HPV, I think that condom use (or having fewer sexual partners) is less necessary."

First, the good news:  Only 4% of the girls felt less of a need to practice safe sex because of the vaccine.  The investigators then looked at what factors were associated with this belief.  Some risk factors were predictable, but a few were surprising.  A lower perceived need for safe sex was associated with:

• Lower knowledge about HPV and the vaccine
• Lack of condom use at last intercourse
• Lack of maternal communication about the HPV vaccine
• Teacher or physician serving as the source of HPV vaccination information

The last one threw me for a loop.  Surely the most reliable information about the vaccine and STDs comes from doctors and sex education teachers?  The problem is that even if they are dispensing appropriate advice (which may or may not be a correct assumption) , they may not be doing so in a way that's understandable to teens and their mothers.  On the flip side, it looks like moms can have a positive impact in their daughters' behavior, particularly if they talk to them about the limitations of the vaccine, including its lack of protection against some HPV strains, other STDs and pregnancy.

Though very few girls agreed that the vaccine would allow them to have more unprotected sex, survey answers don't necessarily predict behavior.  Even before the vaccine, over half of the adolescents in this clinic were sexually experienced, and most were not using condoms reliably.  It's doubtful that the vaccine will decrease the rate of unsafe sexual practices, unless it's accompanied with appropriate counseling.

So does this mean we shouldn't be vaccinating our daughters against, because of the theoretical increased risk of unsafe behavior?  Of course not.  The advent of effective antiretroviral therapy for HIV in the late 1990's was accompanied by an increase in the rate of unprotected sex, and subsequent gonorrhea and syphilis epidemics, in gay and bisexual men.*  Yet it would be completely unethical to withhold effective drug therapy because of its unintended behavioral consequences.  No, it simply means that doctors and, more importantly, parents have our work cut out for us when it comes to educating our kids.

*Despite the increases in other STDs in the San Francisco Bay Area, there was no increase in the HIV incidence in gay men during this time period.  The theory is that HIV-positive men had unsafe sex only with HIV-positive men, and HIV-negative only with HIV-negative.

Still Smoking? Think of the Children!

How's the second week of winter break going for you?  How many times have you screamed at your kids?  Fed them Christmas candy for breakfast?  Confiscated your toddler's new set of horns, a gift from your relative with a grudge?


I've found a surefire way to cheer myself up whenever I feel exhausted and guilty at the end of a Bad Mommy day.  No, I don't look through my kids' "You're the best mom in the world!" cards -- you do realize their teachers force them to write that.  No, I cope by thinking about other women who are much worse mothers than I am.  I'm talking celebrity moms.  Moms who are impossibly rich and beautiful but can't be bothered to whip up some Kraft mac n' cheese.  Moms like Britney Spears, who not only smokes around her kids, but also allows them to play with her cigarettes and lighter.

It's probably not fair of me to pick on poor Britney.  If the paparazzi were tailing my family, they'd probably catch my kids setting the dog on fire.  And I wouldn't look half as good in that bikini.

While Brit probably knows about smoking's ill effects on her own health, she may not be fully aware of the dangers of secondhand smoke, including increased risks of sudden infant death syndrome, ear infections, and asthma, not to mention a higher likelihood that her own children will smoke in the future.  In fact, half of parents who smoke claim they have never been counseled by a pediatrician to stop.


Keeping your child healthy should be a powerful motivation to quit, but is this protective instinct enough to overcome the addiction?  A meta-analysis published in Pediatrics this week found that programs that counsel parents on the dangers of secondhand smoke do increase the chances of quitting successfully, though the benefit was small: 23% in the intervention groups quit, compared to 18% in the control groups.  Interestingly, parents of children over the age of 4 were more likely to quit with counseling, while those of younger children weren't.  The authors speculated that despite the increased risk of SIDS, mothers with newborns may be less able to stop smoking during this particularly stressful time.  Another possible reason is that as kids get older, parents may be more motivated to model healthy behaviors.


So for those of you still trying to quit, stick with it.  Make a New Year's resolution.  Ask your pediatrician to give you a pep talk at your child's next visit, and make an appointment with your own doctor to see if you should be prescribed any medication to help you quit.  Don't be surprised if this is the hardest thing you've ever had to do.  In fact, the tobacco companies are on to you -- there are more cigarette ads in January and February than any other month.  If you relapse, don't beat yourself up.  It takes the average smoker eight tries before she's able to quit for good.  


If all else fails, just think of Britney.

 

The Kindest Cut, Part 2

Looks like I chose a touchy subject for my last blog post; there appear to be quite a few men mourning the loss of their infantile foreskin.  Let me summarize some of the arguments made against my opinion on male circumcision, with my responses:


1.  You cherry-picked studies showing a benefit for male circumcision.  It's true that while numerous observational studies have shown a benefit in terms of UTIs and STDs, there are some studies finding no effect, or even an opposite effect.  Non-experimental, observational studies are fundamentally flawed for this reason.  That's why it's so important to look at randomized, controlled trials whenever possible.


2.  The risk of UTIs in male infants is low and does not justify circumcision.  I totally agree.  The reduction in UTIs alone is not large or clinically important enough to advocate for this procedure.


3.  The trials in Africa are flawed because they weren't double-blinded, and they were stopped early.  OK, YOU design a study that does sham circumcision in the control group, and try to get that past an ethics committee.  Stopping a trial early because of a significant benefit in the treatment group (and offering it to the control group) is the most ethical thing to do in this situation, since HIV is a life-threatening disease.  It is true that stopping a study early for this reason tends to overestimate the benefit, and I might be suspicious of the results if they were seen in only one trial, but in fact, the benefits were seen in all three studies, in different parts of Africa.  The Cochrane Group, which is extremely conservative in its recommendations, concluded, "Research on the effectiveness of male circumcision for preventing HIV acquisition in heterosexual men is complete.  No further trials are required to establish this fact."

4.  The trials in adult heterosexual African men don't apply to infants in the developed world.  The majority of HIV infections in the U.S. and worldwide are due to unprotected sex.  Sure, the absolute reduction in HIV infection with circumcision will be lower in the U.S. than in some parts of Africa, but relative risk reductions tend to remain constant over various patient populations.  I do agree that if you're in a part of the world with extremely low rates of HIV infection (such as Australia -- which has a 0.004% annual risk of infection), routine circumcision may not make economic sense.


5.  Why not promote safe sex instead?  I'm not saying circumcision should be done instead of teaching safe sex.  HIV prevention needs to be multi-pronged, and must also include education, free condom distribution, low-cost antiviral treatment (which reduces transmission rates) and needle exchanges.


6.  Infants die from circumcision, and parents shouldn't be making this decision for them.  Yes, babies will rarely die from circumcision, just as people will rarely die from having IVs inserted into their hands or having a severe allergic reaction to antibiotics (both of which I have seen).  But AIDS is still a huge killer, even in developed countries.  As for parents who want to let their sons make the decision about circumcision once they come of age, I think that's fine.  Just realize that adult male circumcision is a bigger procedure, often involving general anesthesia, and may not be covered by insurance plans when done for purely preventive reasons.


7.  Your story about Dr. Nick operating on your kid sounds fishy.  Nope, absolutely true.  I got a list of low-cost providers because I gave birth at my own, public county hospital.

8.  You're a terrible mom.  OK, I will concede that in the moment that I let Dr. Nick circumcise my son, I was a terrible mom.  I'm an imperfect parent, which is why I think a lot of people read my blog.  If I had to do it all over again, I would still have my son circumcised, but I'd go with this guy instead:

Extra credit if you can name this Simpsons character*

9.  The foreskin is a part of normal male anatomy, and removing it is mutilation.  It occurred to me that this argument probably should have been #1, as many of you have a philosophical objection to circumcision.  You think it's wrong to remove normal foreskin for any reason, and I don't.  There's nothing we can say that will change each other's minds on this point. 

And so we have a parting of the ways.

 *It's Krusty the clown's dad, Rabbi Hyman Krustofski.

The Kindest Cut?

When J.J. was born, our hospital gave us a list of outside physicians who performed circumcisions.  My husband called every provider on the list and made an appointment with the second cheapest one -- the same process by which he selects a bottle from a restaurant wine list.  I knew we were in trouble when we were greeted by none other than....

"Hi everybody!"

Actually, Springfield's Dr. Nick was way more professional than this joker, who was dressed in a hospital gown and dirty sneakers.  Without introducing himself or asking if we had any questions, he whipped out his instruments and started operating.  Rick fled, leaving me to comfort J.J. with a bottle.  In the middle of the procedure, the doctor (at least, I hope it was a doctor) said, "Here, hold this," and he handed me the thingy clamped to my son's penis, as he snipped away.  (I'm not a pediatrician or a surgeon, but I assure you that "thingy" is a formal medical term used by internists.)  And no, I wasn't wearing gloves, nor had I told this guy that I was a doctor. I fretted for days that J.J. would develop Fournier's gangrene, and that I would be to blame for his future as a eunuch.  

Fortunately, the risks of circumcision in a developed country are rare (0.2-0.6%) and minor -- typically bleeding, which usually stops on its own.  (We doctors have a saying: "All bleeding stops....eventually."  Think about it.)  But some would argue that there's no reason to put a baby under the knife when it isn't necessary.  And then there are those whack jobs (no pun intended) who blame their unhappy sex life on the loss of their infantile foreskin, not realizing that they can't get a date because they are whack jobs who blame their unhappy sex life on the loss of their infantile foreskin.  In fact, observational studies have been all over the map in terms of whether circumcision is linked to sexual dysfunction.


There are no randomized, controlled trials of circumcision in infants, and there probably never will be.  Since there aren't any studies employing sham mohels, we must rely on the results of observational studies to guide us on the risks and benefits of neonatal circumcision, with their imperfect corrections for baseline differences.  The procedure is linked not only with certain religions, but also with socioeconomic status, with babies born at higher income levels being more likely to be circumcised -- although Dr. Nick and his like-minded colleagues remain a low-cost option for the uninsured.


Circumcision does seem to reduce the risk of urinary tract infections in the first year of life - from 1% to 0.1%.  Not a huge absolute benefit for a surgical procedure, though infant UTIs do present a significant healthcare cost burden.  My pediatrician friends tell me that kidney ultrasounds are routinely performed in male infants with UTIs, to screen for anatomic abnormalities.  They often have to perform suprapubic aspirations (sticking a needle through the skin into the bladder) to obtain a clean sample of urine, which is a low-risk procedure, but not a particularly fun one for baby or parent.


Observational studies have also shown that circumcision is associated with a lower risk of sexually transmitted diseases, including HIV and human papillomavirus, the cause of most cervical, anal and now, oropharyngeal cancers.  But here the data get particularly sticky, since uncircumcised males are more likely to come from a lower socioeconomic status, which in turn, is associated with a higher rate of STDs.


Although there aren't any experimental studies of infant circumcision, there have now been three large randomized, controlled trials of circumcision in over 10,000 adult men.  All of these studies were performed in Africa, with the primary outcome being the subsequent rate of HIV infection.  It turns out that the foreskin is replete with special cells that are prone to invasion by the AIDS virus, so removing the foreskin should reduce the rate of HIV infection.  And indeed it did, by an impressive 50% over a 2-year period.  In fact, all three trials were stopped early, and circumcision was offered to the men in the control groups.  The studies also found reduced rates of HPV infection in both the circumcised men and their female partners.  


Now, a 50% relative reduction is a big deal in parts of the world with high baseline rates of HIV infection.  In these African studies, only 56 members had to be trimmed to prevent one infection at 2 years.  Of course, if you circumcise a baby, the point it to try to reduce his lifetime risk of infection.  The 2004-2005 U.S. data show that the lifetime risk of HIV infection in men is 1.87%.  Some of those are acquired from injection drug use or maternal-child transmission, but the vast majority of infections are due to unprotected sex.  Circumcision should decrease a child's risk of HIV infection, though the magnitude of benefit in the U.S. and other developed countries is unclear, not to mention the risk reduction in the future partners of these boys.

As for the drawbacks of circumcision in the African trials, there were but a few.  Some of the more pleasant "side effects" of the procedure were enhanced sensitivity and sexual satisfaction -- finally, a randomized (if not blinded) trial putting to rest the question of sexual dysfunction.  In fact, some of these trials found increased rates of unprotected sex and number of sexual contacts in the circumcised groups.  The increases were marginal, but remember that they were observed in an experimental setting.  Now that the benefits have been well-established, what if men got the mistaken notion that circumcision was completely protective against HIV, blunting the potential benefits?    I doubt this will be much of an issue in pediatrics, as I can't imagine any parents encouraging their son to sow his wild oats simply because he had been circumcised.

Whatever the studies show, most parents will probably still base their decisions on cultural and personal reasons.  Rick and I had no discussions at all about the benefits and risks of the procedure. I deferred to my husband's wishes, and when it comes to circumcision, that seems to be the rule among the couples we know.  In 1999, the American Academy of Pediatrics acknowledged the "potential medical benefits," but state that "these data are not sufficient to recommend routine neonatal circumcision."  Some have argued that the AAP needs to advocate more strongly for circumcision, now that we have proof that it saves lives.  

As for all you expecting, uncircumcised dads, maybe it's time to start a new family tradition.


*As a doctor, I know I should always use the correct anatomical term.  I fear, though, that too many mentions of the P-word will result in hordes of perverts stumbling on to my blog via their search engines.  (A lot of boys looking for "Girls Gone Wild" were no doubt disappointed to find themselves instead reading about cervical intraepithelial neoplasia.)

The New Merchants of Death

Why buy your carcinogens when you can get them for free?

Imagine a place where a child is allowed to buy cigarettes for herself, with only a permission slip from her parents.  In many instances, she may smoke her first pack with her mom -- a popular mother-daughter bonding activity. The tobacco industry is completely unregulated, minimizing the risks and touting the health benefits of cigarettes.  A popular T.V. celebrity extols the virtuals of the GTL lifestyle -- Gym, Tobacco, Laundry.

Sounds like a scene from a developing country?  Substitute "indoor tanning" for "cigarettes," and what I've described takes place in all 50 states in the U.S.  The comparison of tanning salons to smoking may sound like hyperbole, but consider the similarities:

Indoor tanning causes cancer. 

A 2007 meta-analysis of 19 studies in over 7,000 patients found that indoor tanning is associated with a 15% increased rate of melanoma, the deadliest of all skin cancers.  That may not sound like much, but when the analysis looked specifically at indoor tanning in those under 35 years old, there was a 75% increased rate of melanoma.  There was also a higher risk of squamous cell carcinoma, which is not as lethal, but more common.

Most of these studies were "case-control," meaning they looked at the rates of indoor tanning in those who had been diagnosed with melanoma versus those who hadn't.  Sure, you could argue that these findings weren't based on randomized, controlled trials, and that people who go to tanning salons are also more likely to sunbathe (just as smokers are more likely to drink and overeat).  But there is also a large body of laboratory evidence that UV radiation, whether natural or artificial, induces skin cell mutations, the first step in carcinogenesis. 

The tanning industry minimizes risks and promotes questionable health benefits.

Just as the tobacco companies marketed filters for "safer cigarettes," so the tanning industry pushes the concept of the "safe tan."  Many companies claim to use only UVA, which is less likely to cause sunburns than UVB.  The problem is that both forms of radiation are carcinogenic.  Moreover, one can still get burned in a tanning booth, and there are even case reports of patients requiring treatment in a burn unit following indoor tanning. 

The other argument for a "controlled" indoor tan is that the increase in melanin protects against burns from natural sunlight.  Many people using tanning booths to prep themselves for sunbathing.  A tan is indeed protective against a sunburn, with a whopping SPF level of 3.  Do they even make sunscreen with that SPF level?  Increased use of tanning beds has also been associated with more frequent sunburns, so any so-called protective effect is a myth.

One fascinating review compared the advertising tactics of the tobacco and tanning industries.  Both, for example, use physicians in their ads:

Text: "After working 16-hour shifts for my residency,

I tan because it recharges me for work tomorrow."

More recently, the industry has trumpeted the benefits of tanning on raising vitamin D levels:

This claim is wrong on so many levels.  Vitamin D deficiency is most frequently seen in the elderly and housebound, not exactly the GTL demographic.  You need only 15 to 45 minutes a week of sunlight in order stimulate adequate vitamin D production; a 15 to 30-minute indoor tanning session is equivalent to a day on the beach.  Finally, only UVB stimulates vitamin D production.  If a tanning salon advertises that it uses only UVA, then the vitamin D argument is patently false.

The tanning industry targets youth. 

A recent study showed that 10% of kids ages 12 to 18 have used a tanning bed at least once in the previous year.  The figure is highest in teenage girls ages 15 to 18, with a 25% indoor tanning rate.  The incidence of melanoma is increasing more rapidly than that of any other cancer in the U.S.  Take a wild guess which population is fueling this rise: young females, with a 2.7% annual increase.

Everyone in my generation remembers Joe Camel.  But even old Joe wouldn't stick his oversized proboscis into a kids' magazine.  Not so with tanning salons.  A survey of high school newspapers in the Denver area showed that almost half carried ads for indoor tanning:

Indoor tanning can be addictive.  

In a survey of 229 college students who used sunbeds, almost 40% met psychiatric criteria for addiction to indoor tanning.  When we're exposed to light, our brain produces melanocyte-stimulating hormone (MSH) in order to ramp up production of skin melanin.  A byproduct of MSH production is beta-endorphin, a natural opioid.  Many users report a sense of relaxation and well-being following a round of indoor tanning, and you can actually block this euphoric response by administering an opiate antagonist.

Daylight saving time is ending soon, and many will be tempted to catch their rays indoors.  This week, California became the only state in which minors will not be allowed to indoor tan (starting in 2012), even with parental permission.  For those of you in the remaining 49, ask yourself: Would I buy cigarettes for my teenager?  If the answer is no, then you know what to do with that tanning permission slip.

Protect the Girls -- Vaccinate the Boys!

 Mommy, why are we looking at hats for Siamese twins?

That's a photo of my then-5-year-old son J.J., shrinking in terror when I dragged him into Victoria's Secret.  Poor guy -- there's surely nothing more mortifying than bra shopping with your mom (unless it's bra shopping with your grandma). I do realize that one day, hopefully far in the future, my innocent little boy will have a very different reaction to all those scantily clad plastic torsos.  And when he reaches that age, it will be my husband's and my solemn responsibility to guide and protect him against STDs.  So naturally we'll be enrolling him in an abstinence-only sex ed program.*

Kidding, folks!  Remember, I'm Evidence-Based Mommy, not Delusional Mommy.

Last week, I reviewed the data on the HPV vaccine for girls.  In addition to cervical cancer and genital warts, HPV causes the vast majority of penile and anal cancers, although these are much rarer.  Gardasil has been FDA-approved for use in males ages 9 through 26.  So what is the evidence that it works in this population?  And now that J.J. is on the cusp of turning 9, should I be asking his pediatrician for this series of expensive shots?

As with the HPV vaccine trials in women, there are no large studies in preteens, but again, the idea behind immunizing children is to protect them before they are potentially exposed to the virus in their teens or young adulthood.  The largest trial randomized over 4000 males ages 16 to 26 to the 4-strain HPV vaccine vs. placebo.  ("Efficacy of quadrivalent HPV vaccine against HPV infection and disease in males.")  The marketing geniuses at Merck couldn't come up with a snappy acronym this time, but I liked my Scrabble-savvy friend's suggestion of SPAWN, for Stop Penectomies** and Anal Warts Now.  Six hundred of the participants reported having sex with men, a major risk factor for HPV infection.

As in the female trials, the vaccine was quite effective in patients who were uninfected at baseline, with an 84% reduction in genital lesions (mostly warts) in those who received all three shots.  The benefit in the population as a whole was significantly less, but still a decent 60% reduction.  Three precancerous penile lesions occurred in the placebo group and none in the vaccine group, but SPAWN wasn't large enough, or of sufficient duration, to detect a difference in these rare neoplasms.

Despite the clear benefit in reducing genital warts, the most frequent and more politically palatable argument for immunizing boys is to protect girls against cervical cancer.***  So should the HPV vaccine be mandatory in boys?  As much as I feel that males should shoulder some of the moral responsibility for their partners' health, in this case, I have to say no.  One of the reasons I've come to this conclusion is that cost-effectiveness analyses have shown that immunizing boys in addition to girls is extremely expensive, compared to immunizing only girls.  The excess cost ranges between $100,000 to a million dollars per year of life gained.****

Having said that, I do plan to sacrifice my eldest son on the altar of public health when his time comes.  Unfortunately for my human pincushion kids, I'm an allopathic doctor who is unabashedly pro-immunization.  Some day they'll thank me for it.

*Evidence has shown that abstinence-only programs are useless in delaying sex.  This is not to be confused with the seemingly oxymoronic abstinence-only parenting.  Telling your child, "Like hell you'll be crashing at your boyfriend's tonight!" has been shown to delay sex.
**A penectomy is an amputation of the penis, standard treatment for penile cancer.  If men were made aware of this, we would have no problem achieving 100% vaccination rates.
***For my gay readers, I apologize for this obviously hetero viewpoint.  There is a much more compelling argument to vaccinate gay males, as the incidence of anal cancer is similar to that of cervical cancer before the era of Pap smears.  The problem with vaccinating only gay males is that by the time a teenager or young adult is comfortable enough to come out of the closet, he may already be infected with HPV.
****Technically speaking, "quality-adjusted life-years" gained.  Since the most frequent manifestation of HPV infection are genital warts, and since warts don't kill you, researchers ask participants to estimate how many years of life they would be willing to give up not to have warts. One study found that having warts was as bad as losing anywhere from 1.6 to 8.3 days of life. ("Cost of treatment and QALYs lost due to genital warts.")  Hard to believe, but I guess I could see how it could get to be over a week if the warts made their cameo on, say, prom night.

Gardasil = Girls Gone Wild?

Stick to your guns, Governor Perry!

Four years ago, Texas governor Rick Perry raised a ruckus when he issued an executive order for all sixth-grade girls to undergo mandatory vaccination against the human papilloma virus, the cause of most cervical cancers and genital warts.  It was a strong and surprising move, especially coming from a politician who believes in teaching kids that cavemen coexisted with dinosaurs.  Critics from the right (and a few from the left) railed against the order, claiming it infringed upon parental rights and taught girls that premarital sex was O.K., despite the fact that the order gave parents the right to opt out of vaccination.  The order was overturned by the state legislature, and mandatory HPV vaccination never went through.  Now that he's running for the White House, Perry is apologizing for his earlier decision, stating, "I didn't do my research well enough."  Was he right then, or is he right now?  Well, Governor, how about if I do the research for you?

The landmark trial that got the HPV vaccine approved by the FDA was the "Females United  to Unilaterally Reduce Endo/Ectocervical Disease," Study, with the totally awesome acronym, "FUTURE II," bringing to mind a popular Disney attraction rather than genital warts.  ("Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions.")  Over 12,000 women ages 15 to 26 years were randomized to three doses of the HPV vaccine or placebo.  The vaccine was designed to protect against two HPV strains that cause 70% of cancers, and two other strains that cause the majority of genital warts.  The primary endpoint, which was carefully selected by Merck, maker of the vaccine, was the rate of cervical cancer or precancer caused by the two HPV cancer-causing strains in women who were not previously infected by these strains.  Got it?  Not the overall rate of all cervical cancer or precancer in all the women, but only a subgroup of cancers in a subpopulation.

The vaccine was extremely effective:  in women without prior infection, the vaccine prevented 98% of cancers and precancers caused by the two strains of virus, and almost 100% formed protective antibodies.  But what if you looked at the entire group of 12,000 women, and all forms of cervical cancers and precancers?  It turns out the efficacy was a disappointing 17%.

So why was the overall efficacy of the vaccine so low?  Two reasons:  First, the women who received the vaccine were still unprotected against the strains of HPV that cause the remaining 30% of cervical cancers.  Second, a good number of the women were already infected with the strains in the vaccine, rendering it useless.

So does that mean we shouldn't bother giving this expensive vaccine because of its low overall efficacy?  Actually, the results of the study strongly suggest that we should be giving the vaccine to girls before they become sexually active.  The CDC reported in 2006 that 70% of girls are sexually experienced by the time they are 19, and another study found that 27% of women aged 20-24 test positive for HPV.  If you follow the American Academy of Pediatrics' guidelines and give the vaccine to presumably uninfected 11- to 12-year-old girls, they should experience a 70% reduction in cervical neoplasms.  I suspect that pharmaceutical companies are probably working on adding more strains to the vaccine, to get the efficacy closer to 100%.

What about the argument that the vaccine will lead to a false sense of security, or an increase in early, sexually risky behavior?  Certainly, there are lot of misconceptions about the vaccine -- for example, that it protects against all cervical cancers, or that you can stop getting Pap smears.  The vaccine shouldn't be given without a fairly sophisticated discussion of the expected benefits.  Presumably, the discussion would be between the parent and the pediatrician, and then ideally, between the parent and the child.  I suspect that a big reason why some parents are reluctant to vaccinate their kids is that they want to avoid an uncomfortable conversation.

As for whether an STD vaccine would be, as one author put it, "a passport to promiscuity," there is very little data.  Four Scandinavian countries recently surveyed 65,000 women about their sexual behavior prior to the introduction of the HPV vaccine.   (Interviewing Swedish supermodels about their sexual proclivities: obviously the brainchild of some repressed male researcher!) They plan on re-surveying them after the vaccination campaign, to see whether it affects their behavior. ("Women's sexual behavior.  Population-based study among 65,000 women from four Nordic countries before introduction of human papillomavirus vaccination.")  HIV vaccine trials have not found an increase in sexually risky behavior among its participants, though many of them were high risk to begin with.  And one survey of adolescent girls found that only about 10% thought that getting the vaccine meant that they were old enough to start having sex.  ("Adolescents' beliefs about their parents' human papillomavirus vaccination decisions.") Frankly, I think most teenagers and young adults are more frightened at the prospect of pregnancy and HIV than they are of HPV, and I doubt the vaccine will do much to alter their behavior.

So should the vaccine should be mandatory in girls?  I say yes, as long as parents have the option to decline.  Making it mandatory would remove its stigma as "the STD vaccine," and countries that have instituted school-based HPV vaccination programs have much higher rates of immunization that those that haven't.  Remember that this wouldn't be the first mandatory vaccine for a sexually transmitted disease; the hepatitis B vaccine is required for elementary school enrollment in most states. 

I do understand the argument that it shouldn't be as compulsory as, say, the measles vaccine, since your child can't catch HPV just by sitting next to an infected person in class.  But if we wait until girls are old enough to consent to the vaccine themselves, it may be too late.  I've seen too many 30-year-olds die agonizing deaths from cervical cancer to let my daughter suffer such a fate.  Even more women have to deal with the infertility resulting from treatment of their cancer or precancerous lesions.  We parents do all that we can to instill our own values into our children, but at a certain point, we have to accept that they will make their own decisions, good or bad.

So man up, Governor Perry!  Apologize for your apology, do the right thing, and become the public health advocate every presidential candidate should be.

Next week:  The HPV vaccine for boys

The End of Chicken Pox?

Medical students are taught that chicken pox pox* are classically described as “dewdrops on a rose petal.”  How the textbook authors got from this:

to this:

is beyond me.  I suspect some dermatologist got a little carried away after taking a creative writing course.  Now, any Boomer mother would be able to diagnose chicken pox in her child without the use of a gardening manual.  But believe or not, there may soon come a generation of doctors who will be unable to diagnose chicken pox by sight alone – and that’s a good thing.  Why?  Because it means that the varicella vaccine is working.

Varicella zoster is the virus that causes chicken pox, and the vaccine has been given to kids in the U.S. since 1995.  The single-dose shot is about 85% effective in preventing chicken pox, and close to 100% effective in preventing severe cases (typically defined as a horrifying 500 or more skin lesions, or requiring hospitalization).  The journal Pediatrics recently published a report showing that the number of deaths due to varicella has dropped by almost 90%.  ("Near elimination of varicella deaths in the US after implementation of the vaccination program”)  In fact, the reduction in mortality exceeded that predicted by computer modeling when the vaccine first came out.

Now if you look at the vertical axis, you’ll see that the absolute number of deaths, even before the advent of the vaccine, has always extremely low.  Most kids who fall ill will do fine with a little chicken soup (or, in my family, chicken jook).  In EBM parlance, the number needed to vaccinate is 3 million kids in order to prevent one death.  But that’s not really why we get our kids vaccinated, is it?  It’s more to prevent the discomfort, inconvenience and lost productivity of a case of chicken pox.  Given that over 90% of today’s adults have been infected with chickenpox, and the 85% effectiveness of the vaccine, that’s a number needed to treat of about 2 to prevent human misery.  And that’s a pretty good number in my book.

One last observation:  Since 2006, pediatricians now give a second, booster dose of varicella vaccine.  The number of breakthrough infections with the 2-dose vaccine is even lower than with the 1-dose.  So if, in the future, your doctor fails to diagnose chicken pox in your child without ordering a blood test, don’t be too hard on him!

(*Sorry, I know that sounds like “woodchuck chuck.”)

I'm Gonna Soak Up the Sun....NOT!

Our family spent the past weekend at the Santa Cruz Beach Boardwalk, and I came home with a stomach full of fried food and a sunburn on the nose.  Luckily, I was more cautious applying sunscreen to the kids, so they managed to escape with nothing more than a deep tan (which I know is still bad for them).

But what is the evidence to support sunscreen as a means of preventing skin cancer?  The medical world has known for some time that sunscreen protects against squamous-cell cancer.  But for melanoma, the deadliest form of skin cancer, the studies have been mostly inconclusive.  Most studies were observational, meaning the researchers just asked participants whether they used sunscreen, and then looked to see whether they developed melanoma.  The problem was that people who were the most prone to getting skin cancer – namely, the fair-haired, freckled folk with a positive family history – were the most likely to use sunscreen, thus confounding the results.

After a prolonged wait, we now have data from a clinical trial showing that sunscreen use does indeed reduce the risk of melanoma – at least if you use it on a daily basis.  The Nambour Skin Cancer Prevention Trial randomized over 1600 adults in Queensland, Australia to either daily sunscreen use or “discretionary” use, meaning the patients could choose when they wanted to apply their sunscreen.  Australia has the highest skin cancer rates in the world, so it was an ideal population to study.  Those in the daily group were given free supplies of broad-spectrum (UVA and UVB protection) SPF 16+ sunscreen and told to apply it to the head, neck, arms and hands every morning and after heavy sweating or bathing.  Many went a step further and applied it to their trunk and legs – why not, if they were getting it for free?  The trial lasted four and a half years, and by the end, the researchers could not find a statistically significant difference in the rates of skin cancer between the two groups.  

Fortunately, the investigators didn’t throw in the towel, knowing that the carcinogenic effects of UV radiation can take years.  They continued to follow the two study groups, long after they stopped giving out free sunscreen.  Turns out that a good portion of the daily sunscreen group couldn’t kick the habit, even after the negative results were published.  Eight years after the trial started, the daily sunscreen group was found to have a lower rate of squamous cell cancer.  Fourteen years after the start of the trial, the researchers published further findings in the January 2011 issue of the Journal of Clinical Oncology:  The rates of invasive melanoma had dropped 73% in the daily sunscreen group.  Finally, here was empirical evidence that sunscreen reduces the risk of melanoma.  The catch?  The absolute risk reduction was quite small, dropping from 1.35% to 0.37%, over the 14-year period.  Now, a 1% absolute risk reduction is actually pretty darn good when it comes to cancer prevention.  The real issue is the cost.  The Journal of the American Medical Association recommends about 21 teaspoons be applied to the average adult for optimal coverage.  Even if one of my children uses, conservatively speaking, only 10 teaspoons a day, an 8 oz. tube of Banana Boat Kids would last fewer than 5 days.  At about $7.00 per 8 oz., that’s $539 per kid per year, for a minimum of 4 years, and that’s doesn’t include re-applications after water exposure!

Now you could argue that even though the Australian study enrolled only adults, the benefits of sunscreen would probably be even greater in children, which is a good point.  You could also argue that any amount of money is worth the price of your child not developing a lethal cancer, which is a bad point.  I mean, sure, if I knew my child had a 100% chance of developing melanoma without sunscreen, I’d mortgage the house and give up the Peets -- whatever it took to protect her.  But it’s not 100%.  It’s not even the1.35% over a 14-year period seen in the Queensland study.  In the U.S., the annual incidence of melanoma is 0.027% in whites and 0.0017% in Asians.  So if someone (Healthnet, are you listening?) would be willing to supply the daily sunscreen for free, what the heck, I’d do it.  But that’s not likely to happen, and I’d rather make sure my daughter gets the HPV vaccine when the time comes to make a real dent in her risk of cancer.  But that's a topic for another blog entry...