Could a group of Melbourne school girls be responsible for wiping over $1bn off the value of CSL Limited, that darling of the ASX?

CSL manufactures cash cow vaccine Gardasil, which prevents infection by many strains of human papilloma virus and, as a result, has the potential to reduce the incidence of HPV-related cervical cancer.

The product is an Australian invention developed by CSL and is sold under licence by other companies around the world. Gardasil is one of the major props, along with a world class blood products business, supporting a stellar rise in the CSL share price. This year, the price has doubled.

Following news that boys might also benefit from vaccination, CSL shares peaked at $96.67 early this week.

Then reports started appearing on Tuesday about girls at one Melbourne school experiencing dizziness, nausea and fainting after receiving the vaccine. The media picked up the story, giving it a serious shot in the arm. At midday today, shares were trading at $90.32.

The share stumble was also likely prompted by a story that appeared on an American website, Judicial Watch, claiming that Gardasil has caused three deaths in the US. CSL denies any causal connection, saying the site has a “definite anti-vaccine, anti-immunisation agenda”. Nevertheless analysts say that “the news seemed to have gained traction” after a 2.74% fall in CSL’s shares on Wednesday and a 1.72% decline yesterday, reports Fiona Tyndall in today’s AFR.

Various religious groups don’t like Gardasil. And some Christian schools in Australia have decided to ban it, believing vaccinating teenagers girls against the virus will make them more likely to have s*x.

Health professionals stand by the vaccine, saying it’s the needle, not the contents of the syringe, that are causing the reactions. A cancer council, the AMA, the inventor and the minister all say it’s safe.

There have been suggestions, delicately made, that the girls were suffering from a psychological rather than physiological reaction. What role the religious angle may have played in the reaction at Melbourne’s Sacred Heart Girls’ College is mere conjecture, especially since it’s too early to know definitely what led to the girls’ response to the vaccination. 

While the share price impact from the two stories will most likely prove a blip, CSL might have to drop out of one race, as Mark Hawthorne notes in The Age today: “Australian pharmaceutical giant CSL is one of three companies engaged in the race to the magical mark of $100 a share — the other two are Rio Tinto and Macquarie Bank.”