The company says the batches of the vaccine, called Typhim Vi, may contain less antigen than they should.
Antigen is material that prompts the immune system to create antibodies against the bacteria or virus targeted by a vaccine.
Sanofi says there is no safety concern for people who may have been vaccinated with the substandard batches of Typhim Vi.
And the company is not recommending that people go for a booster shot earlier than they are normally scheduled to do so.
But Sanofi acknowledges the recall may lead to a typhoid vaccine shortage.
The company hasn't said how many batches of vaccine are involved in the recall. Nor have they said what caused the problem.