It's a Numbers Game for Merck & Glaxo

6, 11, 16, 18, 31, 33, 45...hike! It may read like a quarterback's snap countdown, but those are actually the numbers of the strains of the sexually transmitted human papillomavirus (HPV) covered by the two vaccines made by GlaxoSmithKlineand Merck.

But GSK is still trying to score with the shots.

Merck's Gardasil vaccine has been on the market for a few years now and it has already hit a wall. Not too long ago, Gardasil was considered to be a major new growth driver for Merck. But Gardasil sales fell by one-third in the first quarter of this year as the company is having trouble getting slightly older females to get the pricy set of three shots. Meantime, GSK's Cervarix has been delayed in getting to the U.S. market over and over again. It could finally win FDA soon. And although the market for the vaccine, which works against the leading cause of cervical cancer, is a challenging one, GSK may have a bit of an edge. The British medical journal "The Lancet" just published a study showing Cervarix works against five HPV strains versus Merck's four. They both go after the two strains that cause most cases of cervical cancer, but GSK's also targets three other strains that are different from the extra two MRK's targets. It's the Glaxo five versus the Merck four.

A "Lancet" editorial also points out that real progress against HPV and cervical cancer, which are a very big problem in the developing world, won't be made until guys get vaccinated. Males carry and transmit the virus. Merck is waiting for an FDA decision on whether it can sell Gardasil to guys.

Perhaps reflecting concerns about the size and growth of the market for HPV shots and GSK's late entry, investors are not enthusiastic about the prestigious publication of the company's robust new test results. As I write this, GSK shares are the biggest percentage loser in big pharma.

Time to call an audible.

Questions? Comments? Pharma@cnbc.com and follow me on Twitter at mhuckman