That looks fake. The phrasing of the last sentence is inconsistent with the surrounding legalese.
In any case, the current public health order is:
https://stlouiscountymo.gov/st-louis-county-departments/public-health/covid-19/public-health-orders/sixth-amended-quarantine-and-isolation-order/
And fully vaccinated is defined as:
"9. “Fully Vaccinated Person” means a person who 14 days prior received a second dose of a 2 dose series or 14 days prior received one dose of a single dose vaccine. A person is not fully vaccinated until this time period of 14 days from the last date of the required dose has lapsed."
