Trial of 2nd Booster Dose of COVID-19 Vaccine

NCT05539703 | Withdrawn

• 1 other identifier: REK 476603
• Study Type: interventional
• Target: N/A
• Locations: 0 countries
• Sites: N/A

Brief Summary

Background Recent studies indicate that a 2nd booster dose is associated with lower risk of severe COVID-19. The studies are based on Israeli registry data, comparing outcomes among individuals who have taken the booster, or not. Interpreting the findings from such non-experimental studies is challenging - there are likely systematic differences between those who accept the offer to take a booster dose, and those who do not. Aim Determine the effect of offering vaccination with a 2nd COVID-19 booster dose on severe COVID-19, measured by hospitalization and death caused by COVID-19. Methods Intervention group: A random sample drawn from the whole population aged 45-64 years with 3 doses of COVID-19 vaccine will receive a personal offer to receive the 4th dose of a COVID-19 vaccine in their municipality. Control group: The rest of the population aged 45-64 with 3 doses, who will receive no such offer. Randomization: The investigators will draw a set of birth dates - can then see who is in the intervention group in Beredt C19 (Norwegian emergency preparedness register for COVID-19) without identifying them individually (personal identification numbers are encrypted). Primary outcome: Hospitalization or death caused by COVID-19 in a period of 10 weeks after invitations are sent. Sample size calculations: 300 000 individuals in the intervention group, assuming risk of the primary outcome is at least 15% lower in the intervention group. (The investigators expect a large proportion NOT to accept the invitation to take the vaccine).

Conditions

COVID-19

Outcome Measures

Primary Outcomes (1)

• Severe COVID-19

  Hospitalization or death caused by COVID-19 starting on day 22 after the invitation is sent to the intervention group.

  To be decided, but no more the 3 months

Secondary Outcomes (5)

• Hospitalization or death

  10 weeks

• Health care utilization

  10 weeks

• COVID-19 infection

  10 weeks

• Health care utilization related to potential side effects

  10 weeks

• Infection, hospitalization or death

  12 months

Study Arms (2)

Intervention groups: Invitation to get 2nd booster

EXPERIMENTAL

Participants in the intervention group will receive an invitation to get a 2nd COVID-19 booster dose. Those who accept the invitation to be vaccinated will receive the vaccine through their municipality's vaccination service.

Other: Invitation to get a 2nd booster dose of COVID-19 vaccine

Control group: No invitation to get 2nd booster

NO INTERVENTION

The control group will receive no intervention.

Interventions

Invitation to get a 2nd booster dose of COVID-19 vaccine OTHER

Participants in the intervention group will receive an invitation to get a 2nd COVID-19 booster dose. Those who accept the invitation to be vaccinated will receive the vaccine through their municipality's vaccination service.

Intervention groups: Invitation to get 2nd booster

Eligibility Criteria

• Age: 45 Years - 64 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Aged between 45 and 64 years
• Registered in the Norwegian national population register
• Have received three doses of a COVID-19 vaccine, with the last dose received at least four months ago.
• Have not previously been offered or recommended a 4th dose for medical reasons

You may not qualify if:

• Persons who have already been offered a 4th COVID-19 vaccine dose.
• Persons in whom COVID-19 vaccination is contraindicated as per the vaccines' Summary of Product Characteristics (SPC).

Sponsors & Collaborators

• Norwegian Institute of Public Health: lead

MeSH Terms

Conditions

COVID-19

Condition Hierarchy (Ancestors)

Pneumonia, Viral; Pneumonia; Respiratory Tract Infections; Infections; Virus Diseases; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Lung Diseases; Respiratory Tract Diseases

Study Officials

• Atle Fretheim, PhD MD

  Norwegian Institute of Public Health

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: We will, to the extent feasible, mask the data analysts to group allocation.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: SPONSOR

Model Details: The trial is designed as a register-based randomized trial. The investigators will draw a random sample from the whole population aged 45-64 years, which will constitute the intervention group and will receive a personal offer to receive a 2nd booster dose of a COVID-19 vaccine in their municipality. The rest of the population aged 45-64 will receive no such offer or information and will serve as control group. The random sample will be defined by drawing a set of birth dates. This allows the investigators to identify persons in the intervention group directly in the Norwegian Preparedness Register for COVID-19 without identifying them individually, since personal identification numbers are encrypted in this database. The random sample will receive the offer of vaccination either (i) via Helsenorge (National online health services in Norway) , or (ii) directly from their municipality.

Study Record Dates

• First Submitted: September 13, 2022
• First Posted: September 14, 2022
• Study Start: October 1, 2022
• Primary Completion: January 1, 2023
• Study Completion: June 1, 2023
• Last Updated: May 29, 2025

Record last verified: 2022-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: We intend to make data available around six months after trial-start. The data will be available for at least 5-10 years.
• Access Criteria: No criteria - anyone who is interested will be given access.