Cord-blood respiratory syncytial virus antibodies and respiratory health
in first 5-years of life.
Abstract
Objective: To determine the potential longer-term effects of maternal
antenatal respiratory syncytial virus (RSV) vaccination, we examined the
association between cord-blood RSV-neutralizing antibodies (RSV-NA) and
RSV infections in the first 2-years of life, RSV-NA at 3-years, and
respiratory health to age 5-years. Methods: Two community-based
Australian birth cohorts were combined. For children with at least one
atopic parent, paired serum RSV-NA levels were compared in cord-blood
and at age 3-years. Weekly nasal swabs were collected in one cohort and
during acute respiratory infections (ARI) in the other. Wheeze history
up to age 5-years and physician-diagnosed asthma at 5-years was
collected by parent report. Results: In 264 children, each log10
increase of cord-blood RSV-NA level was associated with 37% decreased
risk (adjusted incidence-rate-ratio (aIRR) 0.63; 95% confidence
interval (CI): 0.40–1.01) of RSV-ARI and 49% decreased risk (aIRR
0.51; 95%CI: 0.25–1.02) of RSV acute lower respiratory infections
(ALRI) at 12–24 months of age. However, higher cord-blood RSV-NA was
associated with increased risk of all-cause ALRI (aIRR 1.29; 95%CI:
0.99–1.69), wheeze-associated ALRI (aIRR 1.75; 95%CI: 1.08–2.82) and
severe ALRI (aIRR 2.76; 95%CI: 1.63–4.70) at age 6–<12
months. Cord-blood RSV-NA was not associated with RSV-ARI in the first
6-months, RSV-NA levels at 3-years, or wheeze or asthma at 5-years.
Conclusions: Higher levels of cord-blood RSV-NA did not protect against
RSV infections during the first 6-months-of-life, time-to-first RSV-ARI,
or wheeze or asthma in the first 5-years of life. Additional strategies
to control RSV-related illness in childhood are needed.