HaKatan,
Yes, vaccine manufacturers are subject to the same scrutiny as are all the rest of their pharmaceutical manufacturing operations. The US Government has a well deserved reputation for insuring quality of pharmaceuticals. (And we would not want it any other way.)
Regarding profit, vaccine manufacturers often sell their vaccines to government agencies or nonprofits. The government has much better leverage at negotiating prices that does the private sector and as a result the vaccine manufacturers only make a small profit on each dose. (Had the Republicans permitted this kind of negotiation for Medicare Part D, a lot of money would have been saved, but they wanted to pay off the pharmaceutical industry for their support.) Vaccines are also time consuming to produce taking much longer than modern synthetic pharmaceuticals and therefore costing much more to produce. So vaccine makers do earn a profit, but not a large one. Any pharmaceutical company would do much better with a big selling cholesterol drug for which they can (and do) charge any price they wish.