The incident occurred in Ping area of Frontier Region Tank, a semi-tribal belt bordering the troubled South Waziristan Agency.
Those kidnapped included a doctor working for the World Health Organisation, a supervisor, a driver and three personnel from the Levies militia.
Police launched a search operation to trace the abducted persons.
No group claimed responsibility for the kidnappings though such incidents are usually blamed on the outlawed Pakistani Taliban, which has banned polio vaccinations in the tribal belt till the US stops its drone strikes.
Dozens of health workers and policemen have died in attacks on polio vaccination teams in the country's northwest and Karachi in recent years.