Introduction:
We aimed to assess the influence of infection history in pediatric patients with Kawasaki disease (KD) on vaccine immune responses in the convalescence stage.

Material and Methods:
In this study, a total of 298 pediatric patients who were diagnosed with KD between January 2021 and December 2024 and completed follow-up were included. They were assigned to a high infection burden group (n = 152) and a low infection burden group (n = 146). All pediatric patients underwent immunization with measles-mumps-rubella (MMR), hepatitis B, or varicella vaccine at least 11 months after treatment with intravenous immunoglobulin, and completed serological tests within 1-3 months after vaccination. Antibody levels were measured via enzyme-linked immunosorbent assay, and the positive conversion rates and geometric mean titers (GMTs) were calculated.

Results:
Compared with the low infection burden group, the high infection burden group had a significantly lower positive conversion rate (82.2% vs. 93.2%, p = 0.006) and GMT (320 IU/ml vs. 540 IU/ml, p = 0.010) of measles antibody. High infection burden was independently associated with a higher likelihood of immunization failure in multivariate logistic regression analysis (odds ratio [OR] = 2.35, 95% confidence interval [CI]: 1.20-4.62, p = 0.013). Quartile-stratified analysis indicated that the measles antibody level declined significantly with increasing infection frequency (p for trend = 0.003).

Conclusions:
A history of high infection burden was associated with lower vaccine-induced immune responses. In particular, frequent respiratory tract infection can significantly weaken the vaccine-induced immune responses in the convalescence stage.