Use and Effectiveness of COVID-19 Vaccines Using State Vaccine Registries and Insurance Claims Data

The vaccine effectiveness (VE) of BNT162b2 COVID-19 vaccine (e.g. KP.2 monovalent formulation) in preventing post-COVID health conditions will be assessed (Aim 1). This aim will utilize a retrospective cohort time-to-event design and evaluate the VE among vaccine-eligible patients from when the vaccine was authorized or approved (specified by age group) through the most current data available. Patients will be sourced from HealthVerity and includes patients who are enrolled in the claims database; data from the state's deidentified vaccine registry will be used to supplement claims data. Patients who will be followed for the PCC endpoint must be eligible to receive the vaccine during the study period. Comparisons between the vaccinated and vaccine eligible but unvaccinated (i.e., no receipt of the most recent formulation) groups will be made using descriptive statistics, incidence rates, and hazard ratios.

The second part of the study (Aim 2) will use a retrospective cohort design to describe the uptake of the vaccine in specific groups over time. Subjects will be identified through three different methods: 1) by analyzing all available dosing records in the Immunization Registry, 2) by using HealthVerity claims data based on specific calendar time periods when the vaccine was available, or 3) based on the start of pregnancy that occurs after EUA date. Patients will be followed until experiencing the vaccination under study, disenrollment, end of data or death. Vaccinations will be assessed overall and also by specific type of prior dose (mRNA vs other).

Aim 1:

Inclusion criteria

Patients must meet all of the following criteria to be eligible for inclusion in the study:

• Patients are required to have a COVID-19 diagnosis on or after September 5, 2024 AND no later than August 26, 2025
• Patients in HealthVerity database and residing in California or Louisiana as of index date AND
• Have ≥1 year of pharmacy and medical enrollment in HealthVerity prior to cohort entry date, allowing for up to a 30-day gap in enrollment AND
• ≥18 years old as of index date AND
• Have resided only in their respective state (California or Louisiana) for ≥1 year prior to index date

Exclusion criteria

Patients meeting any of the following criteria will not be included in the study:

• Patients who were immunocompromised from 1 year prior to cohort entry OR
• Patients who received any 2024-2025 formulation of the COVID-19 vaccine prior to authorization (22 August 2024) OR
• Patients who have discrepancies in sex and/or year of birth between HealthVerity claims and state immunization registry datasets OR
• Patients who had a prior diagnosis of COVID-19 ≤180 days preceding cohort entry OR
• Patients who received any 2024/2025 formulation of the COVID-19 vaccine within 0 to 13 days prior OR 0 to 29 days post index COVID-19 diagnosis (i.e., -13 to +29 days around the index date)

Aim 2:

By Age, Bivalent (older children, adults)

Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

• Has medical and pharmacy enrollment in HealthVerity as of August 31, 2022
• And is age ≥12 years
• With 6 months of continuous medical and pharmacy enrollment before calendar index date
• And does not have evidence of moderate/severe immunocompromise as defined by CDC
• And has evidence of ≥2 doses of COVID-19 original vaccine formulation before the calendar index date
• And does not have original vaccine formulation within 2 months before calendar index date
• And does not have a pregnancy start date within 9 months before or any point after calendar entry
• And does not have discrepancies in sex and/or year of birth between HealthVerity claims and state Immunization registry datasets.

This analysis will be stratified by age: 12-17, 18-49. 50-64, 65-74, 75+, which will be measured as of August 31, 2022.

By Age, Bivalent (younger children)

Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

• Has medical and pharmacy enrollment in HealthVerity as of 12 October 2022
• And is age 5-11 years
• With 6 months of continuous medical and pharmacy enrollment before calendar index date
• And does not have evidence of moderate/severe immunocompromise as defined by CDC
• And has evidence of ≥2 doses of COVID-19 original vaccine formulation before the calendar index date
• And does not have original vaccine formulation within 2 months before calendar index date.

By Age, Bivalent (youngest children)

Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

• Has medical and pharmacy enrollment in HealthVerity as of 08 December 2022
• And is age 6 months-4 years
• With 6 months of continuous medical and pharmacy enrollment before calendar index date
• And does not have evidence of moderate/severe immunocompromise as defined by CDC
• And has evidence of ≥2 doses of COVID-19 original vaccine formulation before the calendar index date
• And does not have original vaccine formulation within 2 months before calendar index date.

By Disease Status, Bivalent

Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

• Has medical and pharmacy enrollment in HealthVerity as of 31 August 2022
• And is age >=6 months
• And has continuous medical and pharmacy enrollment for 6 months before the calendar index date
• And has evidence of 1) moderate/severe immunocompromising condition or separately 2) COVID high-risk condition in a period before the calendar index period (lookback times are dependent on the disease and are provided in variable table below)
• And has evidence of ≥3 doses of COVID-19 original vaccine formulation before the calendar index date.

For Pregnant Women, Bivalent

Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

• Has at least 6 months of medical and pharmacy enrollment in HealthVerity as of 31 August 2022
• And is female sex
• Aged 12-49
• And has estimated date of pregnancy start date within 9 months before or any point after the calendar entry date (determined using gestational age algorithm)
• And has evidence of ≥2 doses of COVID-19 original vaccine formulation before the pregnancy start date or 31 August 2022, whichever is latest.
• And did not receive the bivalent dose prior to pregnancy, if estimated pregnancy start date is after 31 August 2022