Streptococcus Pyogenes Carriage Acquisition, Persistence and Transmission Dynamics Within Households in The Gambia: a Longitudinal Cohort Study
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 441
- 试验地点
- 1
- 主要终点
- Prevalence of oropharyngeal swabs positive for GAS each month
研究概览
简要总结
Group A Streptococcus (GAS) is a bacteria which causes severe infections and leads to deadly diseases such as rheumatic heart disease which kills over 300,000 people a year globally, particularly in low-income countries. It is not know how GAS is spread between people, how often people carry GAS in their throat or on their skin without having symptoms, or what factors increase the chance of this occurring. It is important to understand these factors in order to know how to reduce GAS-related disease.
This study will follow 444 people in The Gambia, over 12 months, taking samples from the throats and skin of people living in the same households, and asking questions about themselves and their behaviour, at regular intervals. By taking samples over time, the investigators hope to understand how common it is to carry GAS without having symptoms, how GAS is spread between people, and whether carrying GAS leads to more GAS infections in people or their household members.
The study will use state-of-the-art techniques to look at the DNA of GAS bacteria that we find, and combine this with a mathematical model to investigate how different strains spread to people within and between households in the community.
详细描述
Type of study and design
The study is a prospective, longitudinal (open) cohort study within households in Sukuta, The Gambia. Households will be recruited, and all available household members asked to participate. Households will be followed for 12 months, with up to monthly visits (at least 3-monthly visits), and more frequently for some subgroups of participants.
A total of 45 households will be recruited, including every available household member as individual participants (resulting in a cohort of approximately 450 participant with the average household size in Sukuta being around 10).
Households will be enrolled for 12 months, with enrolment aiming to commence before the rainy season, to ensure that the enrolment period will span one full rainy season, with dry periods either side. Every household will undergo an enrolment visit (MV0), then up to monthly visits (MV1, MV2, MV3 etc., up to MV12) or less frequently if practical constraints arise.
At each visit an oropharyngeal swab, normal skin swab, oral fluid sample and dried blood spot sample will be taken from all individuals, data collected on socio-demographics, social mixing behaviour and clinical examination findings. Examination findings recorded will include evidence of pharyngitis, pyoderma, and scabies. In addition, a blood sample for serum will be taken at the beginning and end of the study for detailed functional immune responses. Swabs will also be taken from any pyoderma lesions, from common touch points in the household such as door handles, and settle plates used inside households.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Households must:
- •Be within the boundary of Sukuta as determined by the 2013 census
- •Have at least 3 members including at least one child under age 18
- •Individuals must:
- •Provide signed (or thumbprinted) informed consent for study participation (obtained from a parent or guardian for children under the age of 18
- •Be willing and have capacity to participate and comply with the study protocol as judged by a member of the study team
- •Be resident in the household, with no plans to move outside of the household during the period of study participation
排除标准
- •Households:
- •Less than 80% of individuals living in the household, as defined by the The Gambia Demographic and Health Survey 2013 definition, provide consent to participate
- •Individuals:
- •Consent not provided
- •Has any condition or any other reason that may lead to difficulty or discomfort in obtaining all the necessary samples
- •Is judged by the study team member to be unable or unlikely to participate and comply with the study protocol for the entire study period
结局指标
主要结局
Prevalence of oropharyngeal swabs positive for GAS each month
时间窗: Monthly visits
Oropharyngeal swabs taken at monthly visits will be plated for microbiological culture, and the presence of GAS determined by latex agglutination testing.
Change in GAS-positive swabs per month
时间窗: 1 year
Seasonal changes in GAS-positivity will be assessed over the course of a year.
Incidence of GAS-positive oropharyngeal swabs
时间窗: 1 year
Oropharyngeal swabs taken at each visit will be plated for microbiological culture, and the presence of GAS determined by latex agglutination testing. The incidence of positive swabs in person-years will be calculated
Incidence of GAS-positive normal skin swabs
时间窗: 1 year
Normal skin swabs taken at each visit will be plated for microbiological culture, and the presence of GAS determined by latex agglutination testing. The incidence of positive swabs in person-years will be calculated
Prevalence of normal skin swabs positive for GAS each month
时间窗: Monthly visits
Normal skin swabs taken at monthly visits will be plated for microbiological culture, and the presence of GAS determined by latex agglutination testing.
次要结局
- Sensitivity of GAS isolates to antimicrobials.(1 year)
- Difference in GAS emm type diversity compared to other settings(1 year)
- Difference in GAS-specific serological immune activity between GAS-colonised and non-GAS colonised participants(1 year)
- Difference in GAS-specific mucosal immune activity between GAS-colonised and non-GAS colonised participants(1 year)
- Adjusted hazard ratio for GAS carriage depending on presence of relevant risk factors(1 year)
- Adjusted hazard ratio for GAS symptomatic infection depending on presence of relevant risk factors(1 year)
- The level of GAS tissue tropism(1 year)
- Prevalence of Group C streptococcal carriage(Monthly)
- Prevalence of Group G streptococcal carriage(Monthly)
- Prevalence of Staphylococcus aureus skin carriage(Monthly)
- Seroprevalence of anti-GAS antibodies(Baseline)