Antibiotics administered before or after receiving the CVD 103-HgR vaccine might diminish the effectiveness of the vaccine because the immune response to the vaccine relies on the live attenuated vaccine organisms replicating within the small intestine. We do not know what the optimal interval is between receipt of antibiotics and the Vaxchora vaccine. CDC refers clinicians to the package insert which specifies that CVD 103-HgR should not be given to patients who have received oral or parenteral antibiotics during the preceding 14 days. A duration of fewer than 14 days between stopping antibiotics and giving CVD 103-HgR might be acceptable under certain circumstances, such as if travel cannot be avoided during that 14-day interval.
The package insert, however, does not specify an optimal minimum duration between the completion of CVD 103-HgR vaccination and starting antibiotics. In certain circumstances, antibiotics might be clinically necessary after the vaccine (to treat an unrelated infection), thus clinical discretion is recommended.