A Study of the Effectiveness of Moderna COVID-19 Vaccine

This is an observational cohort study to evaluate real-world vaccine effectiveness and durability of Moderna COVID-19 vaccine among a diverse population at Kaiser Permanente Southern California (KPSC).

The primary objective of this study is to evaluate the vaccine effectiveness (VE) of receipt of Moderna COVID-19 vaccine in preventing SARS-CoV-2 infection and severe COVID-19 disease.

SARS-CoV-2 infection will be defined as a positive antigen test result as well as a positive molecular diagnostic test among symptomatic or asymptomatic participants or a COVID-19 diagnosis code. Severe COVID-19 disease will be defined as COVID-19 hospitalization or mortality.

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Key information

Conditions

SARS-CoV-2 COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

6 month and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Kaiser Permanente Southern California

Pasadena, California, 91101, United States

About this study

This study utilized electronic healthcare data collected within the Kaiser Permanente Southern California (KPSC) integrated healthcare system which provides care to over 4.6 million individuals. Participants in this study received vaccination and were assessed for study outcomes as part of routine care. Vaccination information and study outcome status was assessed using procedure, diagnostic, and laboratory code information. Medical chart review was conducted to assess the association of severe outcomes (hospitalization and death) with COVID-19 illness.

Analyses assessing absolute vaccine effectiveness will identify participants who receive Moderna COVID vaccine from the KPSC electronic healthcare database and match them to unvaccinated participants based on age, sex, race/ethnicity, and data of vaccination (index date). Vaccinated and unvaccinated participants will then be followed-up in the database for the occurrence of study outcomes. Cox proportional hazards regression will be used to compare the relative risk of study outcomes by vaccination status.

Analyses of relative vaccine effectiveness will identify participants who receive specific dose number and formulation of Moderna COVID vaccine (Group N) from the KPSC electronic healthcare database and match them to a group of vaccinated participants with a different dose/formulation type (i.e. Group n-1). Similar matching criteria will be applied. Both groups will be followed for study outcomes and cox proportional hazards regression will be used to compare the relative risk of study outcomes by vaccination status.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Aged ≥18 years at index date (participants aged 6 months through 17 years will also be included after Food and Drug Administration [FDA] authorization to vaccinate younger age groups)
KPSC member for ≥12 months prior to index date through 14 days after the index date (allowing a 31-day gap)

Exclusion criteria

Receipt of a COVID-19 vaccine other than Moderna COVID-19 vaccine prior to or on the index date
Receipt of 2 doses of Moderna COVID-19 vaccine <24 days apart for 2-dose exposed cohort
Receipt of any COVID-19 vaccine <14 days after the index date
No health care utilization and no vaccination from the 2 years prior to the index date through the index date
Occurrence of a COVID-19 outcome <14 days after the index date

Treatment and study plan

Primary outcomes

Number of Participants With SARS-CoV-2 Infection

Time frame: Up to 3 years

SARS-CoV-2 infection is defined as a positive antigen test result as well as a positive molecular test or a COVID-19 diagnosis code.
Number of Participants With Severe COVID-19 Disease

Time frame: Up to 3 years

Severe COVID-19 disease includes COVID-19 hospitalization (hospitalization with a SARS-CoV-2 positive test or a COVID-19 diagnosis, or a hospitalization occurring ≤7 days after a SARS-CoV-2 positive test, with chart review to confirm severe COVID-19 symptoms) and COVID-19 mortality (death during COVID-19 hospitalization).

Sponsors and collaborators

Lead sponsor

ModernaTX, Inc.

Industry

Registry information

Official study title

Real-World Study of the Effectiveness of Moderna COVID-19 Vaccine

Important dates

Study start: 2020
Primary completion: 2023
Study completion: 2023
First posted: Jul 6, 2023
Registry last updated: May 28, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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