Have you read the insert? The first highlighted point may seem odd out of context, but the context is right in front of the highlighted section. It's not saying the vaccine is ineffective, it's saying it is for immunisation in people who currently do not have the flu. The lack of studies mentioned is in relation to its effectiveness in people who take the vaccine whilst already being infected with the flu.
Highlighting the lack of proven effectiveness in children is odd too, since the very same insert states it is not for use in under 18s. It makes perfect sense it hasn't been tested on children.
The Mercury part doesn't even say anything negative, simply that it is an ingredient. There are many things that we know are poisonous in some contexts/quantities, whilst being harmless in others.
Im not sure if you're being disengenious on purpose, or if you simply lack the reading comprehension.
