This study is to assess the post-marketing safety of BNT162b2 products using nationwide population-based database in Republic of Korea.

This study is a retrospective, non-interventional, observational study using Korean Disease Control and Prevention Agency-COVID-19-National Health Insurance Service (K-COV-N) database that includes COVID-19 vaccination/infection and claims data in Korean population. For the primary objective, cohort and self-controlled design will be used for measure of occurrence and measure of association, respectively. For the secondary objective, cohort design will be used for measure of occurrence.

Primary objective:

• To describe the frequency and estimate the incidence ratio of adverse events of special interest (AESIs) following exposure to Comirnaty Injection among individuals aged 6 months or older in the Republic of Korea
• To evaluate the relative risk of AESIs following exposure to Comirnaty Injection among individuals aged 6 months or older in the Republic of Korea, using a self-controlled case series (SCCS) design

Secondary objective:

- To describe the frequency and estimate the incidence ratio of severe COVID-19 outcomes (COVID-19 hospital admission, COVID-19 intensive care unit [ICU] admission, and COVID-19 death).

1. Primary Objectives 1-1. Measure of Occurrence Inclusion Criteria For the measure of occurrence, analytical populations will include following individuals,

   • Who meet the predefined criteria for each study population.
   • With enrollment in the national insurance during the observation period, as well as during the clean window prior to the start of the observation period.

   Exclusion Criteria For the measure of occurrence, analytical populations will exclude following individuals,

   • With diagnosis of AESI during the AESI-specific clean window; or
   • With diagnosis of AESI between first dose and second/third dose of primary series when analyzing for the second/third dose.

   1-2. Measure of Association Inclusion Criteria For the measure of association, analytical populations will include following individuals,

   • Who meet the predefined criteria for each study population.
   • With enrollment in the national insurance during the observation period, as well as during the clean window prior to the start of the observation period; and
   • Who had incident AESI during the observation period. Exclusion Criteria For the measure of association, analytical populations will exclude following individuals,
   • Who do not have both risk and control window time. If an individual disenrolls, dies, or reaches the end of the study period during the risk window prior to accumulating any control window time, he/she will be excluded; or
   • With a diagnosis of AESI during the AESI-specific clean window.

2. Secondary Objective Inclusion Criteria For the secondary objective, the study populations will include following individuals,

   • Who meet the predefined criteria for each study population. Exclusion Criteria
   • None

Individuals who were vaccinated with at least one dose of Pfizer COVID-19 vaccine according to locally approved label in Republic of Korea from 27 February 2021 through 31 December 2023.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.