Schjørring Christel Baagø, Lomholt Frederikke Kristensen, Valentiner-Branth Palle, Dalby Tine, Fuursted Kurt, Slotved Hans-Christian, Harboe Zitta Barrella
Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Artillerivej 5, Copenhagen, 2300, Denmark.
Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, Copenhagen, 2300, Denmark.
Sci Rep. 2025 May 2;15(1):15446. doi: 10.1038/s41598-025-99074-w.
Non-vaccine-serotypes (non-VT) pose a challenge to reducing invasive pneumococcal disease (IPD). Since 2023, serotype 38 IPD has increased in Denmark promoting investigation of this serotype's characteristics. We included all non-VT IPD cases from 2014 to 2024 to calculate annual incidences per 100,000 individuals with 95% confidence intervals (CI). Clinical characteristics and outcomes of serotype 38 IPD were compared with other non-VT IPD in 2022 to 2024. Incidence of serotype 38 IPD increased mainly in children < 2 years, from 0.87 (95% CI 0.02-4.84) to 5.99 (95% CI 2.41-12.34) cases per 100,000 population, whereas the incidence for other non-VT remained stable. SNP analysis, conducted for serotype 38 isolates, revealed that the rise was driven by the ST393 clone with isolates not linked to a region or outbreak. Baseline characteristics and outcomes were similar between the 42 cases of serotype 38 IPD and the 412 other non-VT IPD cases, except for age distribution (p < 0.001) with serotype 38 IPD more frequent in children aged < 2 years (21.4% vs. 3.4%). In conclusion, serotype 38 IPD, driven by the ST393 clone, was the dominant serotype causing non-VT IPD in children < 2 years the last two years, however disease severity was similar to other non-VT IPD.
非疫苗血清型（non-VT）对降低侵袭性肺炎球菌病（IPD）构成挑战。自2023年以来，丹麦38型血清型IPD有所增加，促使人们对该血清型的特征进行调查。我们纳入了2014年至2024年所有非VT IPD病例，以计算每10万人的年发病率及95%置信区间（CI）。将2022年至2024年38型血清型IPD的临床特征和转归与其他非VT IPD进行比较。38型血清型IPD的发病率主要在2岁以下儿童中上升，从每10万人口0.87例（95%CI 0.02 - 4.84）增至5.99例（95%CI 2.41 - 12.34），而其他非VT的发病率保持稳定。对38型血清型分离株进行的单核苷酸多态性（SNP）分析显示，其上升是由ST393克隆驱动的，分离株与某一地区或疫情无关。38型血清型IPD的42例病例与其他412例非VT IPD病例的基线特征和转归相似，但年龄分布不同（p < 0.001），38型血清型IPD在2岁以下儿童中更常见（21.4%对3.4%）。总之，由ST393克隆驱动的38型血清型IPD是过去两年2岁以下儿童中非VT IPD的主要血清型，然而疾病严重程度与其他非VT IPD相似。
