Does the divided dose of yellow fever vaccine present a greater risk of adverse reactions?

The fractional dose comes from the same full dose vaccine. It has been given to millions of people to prevent yellow fever in the past. It is as safe and as effective as the full dose of the vaccine.

Serious adverse effects following a full dose of yellow fever vaccine are extremely rare (less than one per one million people). There is no evidence of increased serious adverse effects when using a fractional dose.

Fractional dosing is currently being used for inactivated polio vaccine (IPV), Rabies and Bacillus Calmette–Guérin (BCG).