Check the Covid FAQ on Carnival.com. Unless they are unable to vaccinated because of medial reasons, I don’t think they’ll get an exception. Where are you sailing from?
Vaccine exemptions for cruises to the Caribbean will be limited to a very small number of children ages 5-11, and teens and adults with a medical condition who can provide written confirmation from their medical provider that they cannot be vaccinated for medical reasons. Our sailings from Florida, Texas, Louisiana, Maryland, South Carolina, Alabama, New York and Virginia will operate under these criteria with the assumption that current restrictions imposed by destinations will remain in place.
Vaccine exemptions for ships departing from California will be accommodated for children ages 5-11 and as required by U.S. federal law (in accommodation of medical reasons and sincerely held religious beliefs).
Vaccine exemptions for sailings to Canada will be accommodated for children 5-11 and for medical reasons, in accordance with destination requirements.
On European voyages, vaccine exemptions will only be accommodated for children ages 5-11 traveling with fully vaccinated parents/guardians, in accordance with destination requirements.
On round trip voyages of 10 days or longer, departing from and returning to North America, vaccine exemptions will only be accommodated as required by law and destination requirements. (Unfortunately, vaccine exemptions are not granted for unvaccinated minors under 12.)