Can someone who never received the polio vaccination get infected with the polio virus in his 30s, or does this only impact young children?
Polio virus can infect the adults also. The only reason we normally don’t see any adult suffering from Polio is because of the fact that they must have received vaccination in childhood. Adults who are especially at risk from Polio are travelers to Polio endemic countries, healthcare workers treating Polio patients and working in a pathology lab. Adults in these scenarios who have never been vaccinated earlier should get 3 doses of Inactivated Polio Virus (IPV) vaccine. Schedule recommended is first dose any time, second dose after 1 month gap, third dose 6 months after the second dose. Adults who come under risk categories, even if had, incomplete vaccination in childhood, should complete the doses with IPV.
But, if you are living in a Polio free country and do not belong to these risk groups, can feel safe with the herd immunity effect in the country.