How many TB vaccines do you have to and how far apart are they?

In the United States, the BCG vaccine is typically given only once, usually to infants or children who are at high risk of developing TB. However, in some countries, such as Japan and Germany, the BCG vaccine is given in a series of two or three doses. The doses are usually given weeks or months apart.

The BCG vaccine is not 100% effective in preventing TB, but it can offer some protection. The protection provided by the BCG vaccine decreases over time, so people who are at high risk of developing TB may need to receive a booster dose of the vaccine.