Cases & Deaths is updated daily at around 4 pm ET.

Vaccination Data is updated daily at around 4 pm ET. County Level details (Total Cases and Total Deaths) are updated in real time throughout the day. 

Data Sources: 

1. CDC (https://covid.cdc.gov/covid-data-tracker/#datatracker-home).
2. The data source for vaccination data is CDC.
3. "County Details" section is sourced from the New York Times.

Explanation: https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html