Thiomersal is half mercury (ethylmercury) and half aspirin in structure. It can kill bacteria, molds, your immune cells, and most importantly your brain cells as it is small enough to cross the blood brain barrier.
It was invented by Eli Lilly company, and used as preservative in vaccines 免役针, immunoglobulin preparations, antivenins, ophthalmic and nasal products 眼鼻药水. Preservatives make products last much longer and thus a lot more profitable.
Its sister compound, methylmercury, a pesticide 杀菌剂 in the 1960s, was responsible for the notorious Minamata disease 水祦病 in Japan and Canada and Basra grain disaster in Iraq. These diseased people displayed neurologic symptoms exactly like autism, which include paresthesias, loss of physical coordination, difficulty in speech, narrowing of the visual field, hearing impairment and blindness.
By numerous individual accounts, the use of thiomersal in childhood vaccines (MMR being the worst) has been linked to sharp increase of autism in the united states during 1980s and 90s. More than 5,000 U.S. families have since filed claims in a federal vaccine court alleging autism was caused by vaccines, most implicating thiomersal. However, the FDA, the WHO and the manufacturer all deny such connection, citing scientific study found no link. It appears that majority of autism sufferers also had weakened immunity to start with prior to their vaccination and abrupt onset of autism symptoms. This might explains why studies employing normal children population did not find statistically significant effect.
On the other hand, thiomersal use in most infant vaccines had been "phased out" since 2001, without anybody admitting any wrongdoings (作贼心虚?). One exception is flu vaccine, which still contains this brain poison. If your child was born in the 1990s and has been suffering from autism, I wish you good luck. For parents worrying about autism from today's vaccines, I can tell you that mercury has already quietly disappeared from government-mandetory vaccines (always double check with your peditrician to be safe). As for optional ones, such as some flu vaccine, you better be careful.
Eli Lilly, the most daring and brave drug company in the united states, sells Prozac and zyprexa.