Chrono-optimizing vaccine administration: a systematic review and meta-analysis.

Area of Science:

• Immunology
• Chronobiology
• Public Health

Background:

• Emerging evidence indicates that the time of day for vaccine administration can influence immune responses.
• This systematic review aims to consolidate research on the impact of vaccination timing on immune responses.
• The study assesses the potential of optimizing vaccination schedules to improve program effectiveness.

Purpose of the Study:

• To provide a comprehensive overview of how vaccination timing affects immune responses.
• To evaluate the role of vaccination timing in optimizing vaccination programs.
• To quantify the effect of vaccination timing on antibody responses through meta-analysis.

Main Methods:

• A systematic literature search was conducted across Embase, Medline, and Scopus.
• Included studies were observational and clinical trials assessing human immune responses to vaccinations at different times of day.
• A meta-analysis focused on clinical trials to determine the effect size of vaccination timing on antibody responses.

Main Results:

• Seventeen studies on COVID-19, influenza, hepatitis B, hepatitis A, and pneumococcal vaccines were identified.
• Eleven studies showed significant effects of vaccination timing on antibody response, with 10 favoring morning vaccination.
• Morning vaccination yielded stronger antibody responses in adults aged 60+, particularly evident in influenza vaccine recipients (SMD = 0.32 in 65+).

Conclusions:

• Morning vaccination enhances antibody responses in adults aged 60 and older.
• This demographic is crucial for influenza and COVID-19 vaccination strategies.
• Chrono-optimizing vaccine administration presents a low-risk, cost-effective method to improve vaccine effectiveness in older adults.