There are a few good reasons to expect that this will not be material, as to Kenilworth. First — but I have not been able to run this to ground yet — in most post-industrial western nations, vaccine makers like Merck and GSK are protected by a series of procedural hurdles, in the local legal systems, that take note of the fact that governmental entities vet and approve the vaccines, and often mandate the administration of them, to an entire population segment.
Because the vaccine maker may only be paid a very small amount per jab (yet have to supply very high volumes of product), the government essentially agrees to shoulder most of the responsibility should wide-spread but ealier latent side effects be seen. I do not know whether any analogous set of protections exists in Japan, but I suspect something along those lines exists.
In addition, the side effect rate for Merck’s vaccine in Japan looks to be around .0006 — less that 60 per 100,000 doses — i.e., a very irregular (but possibly still-emerging) set of off-target effects.
So — I would not expect much movement in either firm’s stock price today, based on this. In any event, here is a bit, from The Japan Times story, overnight:
. . . .Minaguchi said the victims will file the suit sometime after June against the central government, GlaxoSmithKlien [sic] PLC, the maker of Cervarix, and Merck Sharp & Dohme Corp., the maker of Gardsil, at four district courts in Tokyo, Nagoya, Osaka and Fukuoka. . . . Out of an estimated 790,000 people given Gardasil 453 experienced side effects. . . .
In April 2013, after the Diet revised the Preventive Vaccination Law, the health ministry began recommending that girls between the ages of 12 and 16 be vaccinated [but the government has since reversed that decision]. . . .
We will (of course) keep an eye on it — and in the coming days, try to find the answer regarding vaccine courts and shields, on the island. Warm, rainy but now clearing morning — so goes the Big Shoulders’ Spring Thursday. . . smile.