The incidence of invasive group A streptococcal (GAS) disease was increased among young children, with increased rates generally observed among those from low- and middle-income countries (LMICs), according to results of a study in The Lancet Infectious Diseases.

In a systematic review and meta-analysis, researchers used data published between January 2000 and June 2019 to estimate the global incidence of invasive GAS disease. They also estimated the associated case fatality and neurodevelopmental impairment risks among women during pregnancy and the post-partum period, neonates, infants, and children. The analysis comprised 20 studies representing 3829 individuals with GAS disease from 12 countries.

The pooled incidence of invasive GAS disease during pregnancy in high-income countries (HICs) was 0.12 (95% CI, 0.11-0.14) per 1000 livebirths, with high heterogeneity observed (I² =100%). Owing to limited data, the researchers were unable to calculate the pooled case fatality risk associated with pregnancy or the post-partum period.

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The pooled global incidence of neonatal invasive GAS disease was 0.04 (95% CI, 0.03-0.05) per 1000 live births. The incidence per 1000 live births was 0.12 (95% CI, 0.00-0.24) in LMICs and 0.02 (95% CI, 0.00-0.03) in HICs. The overall case fatality risk was 21% (95% CI, 3-38), and the estimated case fatality risk was 61% (95% CI, 33-89) in neonates from LMICs and 3% (95% CI, -3 to 10) in neonates from HICs.

The pooled incidence rate (IR) of invasive GAS disease in infants was 0.13 (95% CI, 0.10-0.16) per 1000 live births, with an increased incidence observed in LMICs (IR, 0.33; 95% CI, -0.22 to 0.88) vs HICs (IR, 0.08; 95% CI, 0.05-0.11). The overall case fatality risk was 14% (95% CI, 4-25), and the risk was 23% (95% CI, -7 to 53) in LMICs and 7% (95% CI, 2-11) in HICs.

The pooled incidence of invasive GAS in children aged 1 to 5 years was 0.04 (95% CI, 0.03-0.05) per 1000 person-years, with further increases observed after the inclusion of those aged 0 to 1 (IR, 0.09; 95% CI, 0.07-0.10). Similar results were noted for the overall case fatality rate, with a rate of 4% (95% CI, 1-7) in children aged 1 to 5 years and 9% (95% CI, 4-15) in those aged 0 to 5.

This study was limited by significant heterogeneity as only 1 of the included studies assessed GAS disease in LMICs. Other limitations included the different study designs, settings, and definitions used for invasive GAS disease.

“These data highlight an opportunity to prevent serious disease, disability, and deaths in the least-served and highest-burden populations worldwide,” the researchers noted. They concluded, “…vaccine strategies could include vaccination of infants, young children, and pregnant women, and be informed by improved data on the burden of invasive GAS in pregnant women and infants in LMICs.”


Sherwood E, Vergnano S, Kakuchi I, et al. Invasive group A streptococcal disease in pregnant women and young children: a systematic review and meta-analysis. Lancet Infect Dis. Published online April 4, 2022. doi:10.1016/S1473-3099(21)00672-1