Are vaccines harmful

Different vaccines have different risks. No medication is 100% without risk, and vaccines are included in that. However, there is always ongoing vaccination monitoring for problems and they would be removed from the market if there were proven adverse effects in more than a fraction of people vaccinated. The FDA has approved for use any that are used in the US and they evaluate all trials and studies for safety and effectiveness before approval. If vaccinations are recommended by your physician, who has already weighed the benefits vs the risks before recommending them, the vaccines are going to be safer than the disease will be if you get it because you did not get the vaccine.

For the flu vaccines in particular:

There is discussion of concerns about flu vaccinations online at various sources. One of those concerns is about traces of Mercury that are in flu vaccines from the preservative used in the vaccines called thimerosal.

There is no scientific data to support the concerns that some have voiced about the preservative thimerosal. There is no direct cause and effect data from scientific studies that link autism or other health problems to the thimerosal. The minuscule amount of mercury in the preservative's compound ingredients is no more than would be obtained through a meal of fish.

However, there are some manufacturers who have developed single doses of flu vaccine that will not contain the thimerosal, which may be available to those who have this concern. The larger 10cc vials will have to have the preservative added, but single dose vials and single dose pre-loaded syringes may be an option for some. Discuss this with your health care professional in advance of presenting for the vaccination if you have these concerns.