The Incidence of Lyme Borreliosis Among Children

Abstract

Background: First recognized in children in the United States, Lyme borreliosis (LB) is the most prevalent tickborne illness in North America and Europe. However, the incidence of LB in children, including geographic variation and difference from that in adults, is incompletely described.

Methods: We compiled surveillance data from public health agency websites reporting age-stratified LB case data, which was combined with census data to derive incidence estimates. Additional incidence estimates were obtained through a systematic literature review.

Results: We identified 18 surveillance systems and 15 published studies for derivation of LB incidence in children. National incidence of >10 cases in children per 100,000 per year were estimated for the United States and parts of Eastern, Western and Northern Europe. However, there was substantial variation in incidence among countries in some European regions. National incidence estimates from the literature largely aligned with estimates from surveillance. Surveillance-reported pediatric incidence was lower than adult incidence in adults in 8 countries, similar to adult incidence in 3 countries, and higher than adult incidence in 1 country. Among all pediatric age strata, the 5-9 years of age stratum had the highest proportion of pediatric cases in most countries.

Conclusions: As pediatric LB represents a substantial proportion of overall LB incidence across countries in Europe and North America, LB prevention and control efforts should target pediatric as well as adult populations. However, better data are needed to fully characterize the difference in incidence across geographic regions.

FIGURE 1.

Incidence of LB in children from surveillance systems (2005–2020). Age cutoff varies by country, based on available age-strata, indicated in parentheses. Denmark and Ireland only report LNB.

FIGURE 2.

Ratio of surveillance-reported incidence in children versus adults (95% CI). Incidence is averaged across years of available surveillance data. Countries with incidence in children <5 of 100,000 CPY not included (Canada, Denmark, Japan, Ireland, Portugal, Romania, South Korea). Age cutoff varies by country, based on available age strata, indicated in parentheses. Colors indicate WHO region. CI indicates confidence interval; WHO, World Health Organization.

FIGURE 3.

Age distribution of surveillane-reported pediatric LB cases. A: Proportion of surveillance-reported pediatric LB cases. B: Age stratum with highest proportion of pediatric LB cases, by country. Cases include all years of available data. Countries with <30 pediatric cases excluded (Japan, South Korea, Ireland, Portugal). Age strata vary by country.