It is likely exemptions will be issued – for example, your GP can issue you with a medical exemption form if you cannot have the yellow fever vaccine.
However, if you choose not to have the vaccine because you simply don’t want to, this will not be grounds for exemption.
Travel insurance policies do not cover ‘disinclination to travel’ – which is defined as when the policyholder changes their own plans – meaning you won’t be able to claim back the cost of cancellation or if you are refused entry at the airport or border.
Refusing a vaccine could also impact your emergency medical cover, with some policies containing exclusions relating to vaccinations.