“Defining a vaccine breakthrough infection: For the purpose of this surveillance, a vaccine breakthrough infection is defined as the detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person ≥14 days after they have completed all recommended doses of a U.S. Food and Drug Administration (FDA)-authorized COVID-19 vaccine...
As of May 1, 2021, CDC transitioned from monitoring all reported vaccine breakthrough cases to focus on identifying and investigating only hospitalized or fatal cases due to any cause.”
Note: So by definition, anyone getting a one-shot COVID-19 ‘vaccination series’ cannot be counted as a breakthrough case until 14 days after their inoculation. Similarly, people getting a two-shot ‘vaccination series’ cannot be counted as a breakthrough case until 14 days after their second inoculation. Thus, in a system that:
- adheres to this CDC definition, and
- categorizes COVID-19 cases in a binary scheme (e.g., ‘vaccinated’ vs. ‘unvaccinated’),
... inoculation recipients testing positive at the 13-day mark or earlier are counted as not vaccinated. For an example, see ‘King County, WA: COVID-19 Outcomes by Vaccination Status’ below.