Are persons who are medically unfit to be vaccinated allowed to travel under the VTL (Air)?

Persons who are medically unfit to be vaccinated are not allowed to travel under the VTL (Air). Unvaccinated short-term visitors will not be allowed to travel to Singapore. However, unvaccinated:

Singapore Citizens, Permanent Residents and Long-Term Pass holders who have received entry approval via the SC/PR Familial Ties Lane may still travel to Singapore on a non-designated flight.