Longitudinal RSV Antibody Trends in Thai Children (0-8 Years): Association With Seasonal Outbreak Patterns and...

Area of Science:

• Immunology
• Virology
• Epidemiology

Background:

• Respiratory syncytial virus (RSV) causes significant childhood respiratory illness with established seasonal patterns.
• The COVID-19 pandemic altered typical RSV transmission dynamics, leading to atypical outbreaks and raising questions about immunity debt.
• The impact of naturally acquired immunity on RSV transmission in tropical regions requires further investigation.

Purpose of the Study:

• To investigate longitudinal trends in RSV-specific antibody levels in Thai children.
• To assess the influence of the COVID-19 pandemic and associated public health measures on these antibody levels.
• To evaluate the validity of the immunity debt hypothesis in the context of RSV in a tropical setting.

Main Methods:

• Longitudinal study analyzing 3219 serum samples from Thai mothers and children (2015-2024).
• Quantification of anti-RSV IgG antibody levels using Enzyme-Linked Immunosorbent Assay (ELISA).
• Correlation of antibody trends with RSV seasonality, age, and pandemic-related public health interventions.

Main Results:

• RSV antibody levels demonstrated seasonal fluctuations, mirroring Thailand's annual RSV epidemics.
• Children aged 60-72 months during the pandemic showed decreased IgG levels, coinciding with public health restrictions.
• Geometric mean antibody levels dropped in 2022 but rebounded significantly in 2023 after restrictions eased and atypical RSV resurgence.

Conclusions:

• Findings support the immunity debt hypothesis, suggesting pandemic disruptions impacted population immunity to RSV.
• Sustained serological surveillance is crucial for monitoring RSV trends and population immunity.
• The study underscores the importance of robust immunization strategies to mitigate future RSV outbreaks and their impact.