Department of Pathology and Microbiology, School of Medicine, University of Zambia, Lusaka, Zambia.
Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka, Zambia.
PLoS One. 2021 Feb 4;16(2):e0246025. doi: 10.1371/journal.pone.0246025. eCollection 2021.
In Zambia, before rotavirus vaccine introduction, the virus accounted for about 10 million episodes of diarrhoea, 63 000 hospitalisations and 15 000 deaths in 2015, making diarrhoea the third leading cause of death after pneumonia and malaria. In Zambia, despite the introduction of the vaccine acute diarrhoea due to rotaviruses has continued to affect children aged five years and below. This study aimed to characterise the rotavirus genotypes which were responsible for diarrhoeal infections in vaccinated infants aged 2 to 12 months and to determine the relationship between rotavirus strains and the severity of diarrhoea in 2016.
Stool samples from infants aged 2 to 12 months who presented to the hospital with acute diarrhoea of three or more episodes in 24 hours were tested for group A rotavirus. All positive specimens that had enough sample were genotyped using reverse transcriptase Polymerase Chain Reaction (RT-PCR). A 20-point Vesikari clinical score between 1-5 was considered as mild, 6-10 as moderate and greater or equal to 11 as severe.
A total of 424 stool specimens were tested of which 153 (36%, 95% CI 31.5% to 40.9%) were positive for VP6 rotavirus antigen. The age-specific rotavirus infections decreased significantly (p = 0.041) from 2-4 months, 32.0% (49/118) followed by a 38.8% (70/181) infection rate in the 5-8 months' category and subsequently dropped in the infants aged 9-12 months with a positivity rate of 27.2%. 38.5% of infants who received a single dose, 34.5% of those who received a complete dose and 45.2% (19/42) of the unvaccinated tested positive for rotavirus. The predominant rotavirus genotypes included G2P[6] 36%, G1P[8] 32%, mixed infections 19%, G2P[4] 6%, G1P[6] 4% and G9P[6] 3%.
Results suggest breakthrough infection of heterotypic strains (G2P[6] (36%), homotypic, G1P[8] (32%) and mixed infections (19%) raises concerns about the effects of the vaccination on the rotavirus diversity, considering the selective pressure that rotavirus vaccines could exert on viral populations. This data indicates that the rotavirus vaccine has generally reduced the severity of diarrhoea despite the detection of the virus strains.
在赞比亚，轮状病毒疫苗引入之前，该病毒在 2015 年导致约 1000 万例腹泻、6.3 万例住院和 1.5 万例死亡，使腹泻成为继肺炎和疟疾之后的第三大死亡原因。在赞比亚，尽管引入了疫苗，但五岁以下儿童仍持续受到轮状病毒引起的急性腹泻的影响。本研究旨在描述导致 2 至 12 个月龄接种疫苗婴儿腹泻的轮状病毒基因型，并确定 2016 年轮状病毒株与腹泻严重程度之间的关系。
对因急性腹泻在 24 小时内出现 3 次或以上腹泻症状而到医院就诊的 2 至 12 个月龄婴儿的粪便样本进行 A 组轮状病毒检测。对所有阳性样本进行足够样本量的逆转录聚合酶链反应（RT-PCR）基因分型。Vesikari 临床评分 1-5 分为轻度，6-10 分为中度，大于或等于 11 分为重度。
共检测了 424 份粪便标本，其中 153 份（36%，95%CI 31.5%至 40.9%）VP6 轮状病毒抗原阳性。轮状病毒感染率随年龄呈显著下降趋势（p=0.041），2-4 个月龄组为 32.0%（49/118），5-8 个月龄组为 38.8%（70/181），9-12 个月龄组婴儿阳性率下降至 27.2%。接受一剂疫苗的婴儿中，38.5%阳性，接受完整剂量的婴儿中，34.5%阳性，未接种疫苗的婴儿中，45.2%（19/42）阳性。主要轮状病毒基因型包括 G2P[6]36%、G1P[8]32%、混合感染 19%、G2P[4]6%、G1P[6]4%和 G9P[6]3%。
结果表明，异源株（G2P[6]（36%）、同源株 G1P[8]（32%）和混合感染（19%））的突破性感染引起了人们对疫苗对轮状病毒多样性影响的关注，因为轮状病毒疫苗可能对病毒种群产生选择压力。尽管检测到病毒株，但本数据表明，轮状病毒疫苗通常会降低腹泻的严重程度。
