Attempting to prevent illness, including the spread of viral infections through the use of vaccines, is the holy grail of medical science. But do we fully understand the consquences? It’s a sobering reality that doctors too often seem to forget: nearly everything we do in this business, which is always supposed to make things better for patients, inevitably generates at least some unforeseen and (far too often) unintended negative consequences. That was, for example, the story behind the promotion of hormone replacement therapy —HRT— for menopause. In the end, HRT turned out to harm way more women than it helped.
And it’s also likely to be the same for the use of anti-oxidant vitamin supplements. While they are supposed to help people live longer and better, results from nearly every good study seem to show a small excess number of deaths in those who take such vitamins.
Unfortunately, a similar result – unintended harmful consequences from good intentions – seem to be happening with the relatively recent widespread use of Prevnar®, a vaccine for kids against the seven strains of the pneumococcal bacteria (Streptococcus pneumoniae) that are most likely to cause ear infections. And ear infections in kids are a serious problem, as nearly every parent has discovered at one time, often late at night. Studies estimate that over 80% of kids will develop an ear infection by the age of 3, and many will suffer recurrent infections.
Strep pneumoniae are said to cause between 30% and 50% of all ear infections in kids, so it was hoped that Prevnar® would significantly cut the number of those infections. And it did. Studies done during the first few years after the introduction of Prevnar® estimate that the overall rate of ear infections dropped by roughly 20%.
That’s the good news. The bad news is that a still small but increasing number of kids are now getting severe ear infections from strains of pneumococcal bacteria not covered in the vaccine (one expert recently estimated that there are 91 strains of pneumococci out there). And the even worse news is that these infections are increasingly due to a form of pneumococci that is completely resistant to all the antibiotics we use to treat ear infections.
That’s bad enough, but the potentially even worse news is that we really have no idea what this new reservoir of completely resistant bacteria is going to do, either to the kids who harbor these colonies, or to others – siblings, parents, grandparents, teachers – they may pass the bacteria on to.
Now I am not writing this to scare anyone or to dissuade any parent from giving the vaccine to his or her kids. I would, for example, still give the Prevnar® vaccine to my own kids if I had any at the appropriate ages.
Besides, no one can even say with certainty that it’s the introduction of Prevnar® that caused this resistant bacterial strain to expand its turf so quickly, although the time line is quite suspicious for a causative link between the two events.
What I do want to point out, though, is what I said at the beginning: most “good” medical deeds often turn out to produce some harm, and we often don’t discover that harm or how significant it may be for many years.
That’s why, for example, I’m not nearly as gung-ho as so many others seem to be about giving Gardasil®, the new vaccine against human papillomavirus —HPV— to every young girl in the world in an attempt to reduce the rate of cervical cancer. I am just not convinced that the medical profession knows where this experiment will end.
Since Gardasil® only covers two of the strains of HPV that cause cervical cancer, how do we know for sure, for example, that other strains not covered in this vaccine (or the new vaccine soon to hit the market), will not leap up to predominate? And, can we be certain that young girls who get vaccinated, many of whom will now be convinced that they can’t ever get cervical cancer, won’t let their guard down in protecting themselves against other sexually transmitted diseases? And, might they also stop getting regular Pap smears as a consequence?
Again, I would give this vaccine to my young daughter, if I had one, but I am still concerned that we haven’t seen the last of this story as yet. As was the case with HRT, antioxidant vitamins, and now, potentially, the Prevnar® and HPV vaccines, only time will tell.
If you have a comment or question for Dr. Hister – you can contact him at ahister@knowitallhealth.com
Reviewed September 23rd, 2007