Retrieval of Real World Data for Clinical Research
1.0.0 - trial-use International flag

Retrieval of Real World Data for Clinical Research, published by HL7 International - Biomedical Research & Regulation Work Group. This is not an authorized publication; it is the continuous build for version 1.0.0). This version is based on the current content of and changes regularly. See the Directory of published versions

COVID-19 Vaccine Effectiveness Study

The following use case was used to determine the requirements for determining a patient cohort along with what data elements were necessary when retrieving clinical data:

COVID-19 BNT162b2 Vaccine Effectiveness Study

The details of this study can be found on NCT04848584.

The primary objective of this study is to determine the vaccine effectiveness of 2 doses of Pfizer-BioNTech BNT162b2 vaccine against COVID-19-associated hospitalization. There will be a large retrospective database study using two parallel study designs: a test-negative case-control design and a retrospective cohort design. Exploratory analyses of VE estimates by strain type will be conducted.

Cohort Criteria

The patients for this study would have the following criteria:

  • female or male aged 5 years or greater
  • admitted to hospital with acute respiratory infection
  • received a PCR test for SARS-CoV-2

These criteria would be represented by the following queries:

/Patient?birthdate=le<birthdate of 5 years before today>&gender=male,female

The patients would also not have the following criteria:

  • patients who receive only another newly licensed or investigational SARS-CoV-2 vaccine or COVID19 prophylactic agent prior to hospitalization

This exclusion criteria would be represented by the following query:


The patients that were common to the first three queries and were not found in the exclusion query would form the set of patients representing this cohort.

Retrieved Data

For patients that meet the criteria above, the following data, as a minimum, would be retrieved:

  • patient demographics
  • all Medications from the date of admittance to hospital
  • all COVID test results
  • all vaccination records