Evaluation of the Susceptibility of Human Volunteers With Different Histo-Blood Group Antigens to Norovirus
试验速览
- 阶段
- 1 期
- 状态
- 已完成
- 入组人数
- 40
- 试验地点
- 2
- 主要终点
- Measurement of the number of people who develop symptomatic illness after challenge with Norovirus
研究概览
简要总结
Objectives: To evaluate the role of human histo-blood group antigens in susceptibility to Norovirus infections.
Description of Study Design: Healthy volunteers with different blood types and low antibody titers to the challenge strain will be challenged orally with a Norovirus in the CCCR inpatient facility. Subjects with resistant (non-secretors) or susceptible (secretors (of either A, B or O blood group)) to the challenge strain will be recruited. The challenge study will be conducted in two groups of twenty, each with approximately ten secretors and ten non-secretors. Three additional subjects per group will serve as alternates in the event that any of the study subjects are unavailable or become ineligible at the time of the inpatient study. Subjects will be monitored daily in the isolation facility for at least five days following this challenge for daily clinical and virological evaluations. Subjects will return to the investigational site for evaluation the day after discharge from the inpatient unit and about 30 days (28-35 days) post challenge.
Study Endpoints: Norovirus infection as assessed by viral shedding, seroconversion and clinical illness assessed by the duration and severity of symptoms
详细描述
Noroviruses are single-stranded, positive-sense RNA viruses that cause acute gastroenteritis in humans. The prototype Norwalk virus (NV) was identified in a large outbreak of acute gastroenteritis in an elementary school in Norwalk, Ohio, in 1968. Since then, many strains have been described and named by the locations of their first isolation. Genetically, Noroviruses belong to one of four genera within Caliciviridae (CV). Phylogenetic analysis has shown that the Norovirus genus is divided into five genogroups and each genogroup can be further divided into genetic clusters; at least 30 genetic clusters of Noroviruses have been identified.
Noroviruses have been recognized as the most important cause of non-bacterial epidemics of acute gastroenteritis, affecting individuals of all ages, in both developing and developed countries. Such outbreaks usually have high attack rates and have occurred in child care centers, schools, restaurants, summer camps, hospitals, nursing homes, ships (both civilian and military) as well as deployed military troops. The viruses are highly contagious and are able to survive in the environment for extended periods of time. They are spread by contact with environmental surfaces and person-to-person transmission. Noroviruses normally cause moderate-to-severe diarrhea and the disease is often incapacitating and can be fatal in the young and elderly. The most important public health concern is that Noroviruses can cause large water- and food-borne outbreaks, resulting in the virus being classified as a Category B agent.
Noroviruses have also been implicated in several military outbreaks. The "Desert Shield virus" (DSV) isolated in US troops in the 1991 Gulf War was subsequently identified as a Norovirus. Similarly the recently reported "mysterious" attacks of acute gastroenteritis affecting the British troops in Afghanistan were also caused by a Norovirus. Large outbreaks of Norovirus-associated gastroenteritis are common on US Navy ships, similar to those that occurred on board cruise ship lines. Surveillance of acute gastroenteritis on board five US Navy combat ships in 1998-1999 showed that all the ships experienced large outbreaks of Norovirus acute gastroenteritis during their deployment in the Pacific and Indian Oceans, following port visits. Because of the rapid spread of the disease, many departments and units on board the ships were unable to function during the peak of the outbreaks.
Noroviruses are difficult to study because: 1) they are genetically and antigenically highly diverse and multiple strains with distinct genetic identities co-circulate in the same communities, making diagnosis and disease control extremely difficult; and 2) the virus cannot be cultivated in cell culture and 3) no small animal model for studying Noroviruses exists. The molecular cloning of the prototype Norwalk Virus (NV) in 1990 by one of the co-investigators of this application has allowed rapid progress in studying Noroviruses and other genera; however, many issues on Norovirus infection, pathogenesis, immunology and host range remain unknown.
The discovery of Norovirus receptors provides new opportunities to evaluate the pathogenesis and epidemiology of Noroviruses. A host genetic factor involving Norovirus infection was originally suggested by many researchers before the cloning of Noroviruses in the 1990s because about 20-30% of individuals who did not have antibodies against Noroviruses were never infected following a challenge with NV, and in outbreaks, individuals who remained healthy were clustered in families that had the same exposure to Noroviruses as the ill families. Further, pre-existing antibodies against NV were not protective against NV infection, while individuals who had high levels of antibodies against NV were more susceptible to NV than individuals who did not have the antibodies. These observations indicate that, in addition to immune responses, there must be another factor(s) that controls the host-specificity of Norovirus infection.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Single Group
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 49 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy adults between the ages of 18 and 49 years
- •Willing and able to provide written informed consent
- •Able to comply with all study procedures
- •Have a body mass index of at least 19
- •Have a serum IgG antibody titer of < 1:1,600 to Norovirus
- •Female subjects of child bearing potential must have negative urine pregnancy tests
- •Female subjects must be of non-childbearing potential, or if of childbearing potential (as determined by investigator) must be practicing abstinence or using an effective licensed method of birth control for one month before receipt of challenge through one month after completing the inpatient isolation facility stay.
- •Have normal screening laboratories
- •Score at least 70% on a test of understanding of this research study.
排除标准
- •Expected to be noncompliant with study procedures or planning to move within the anticipated total duration of the study
- •Pregnant or breastfeeding
- •HIV, Hepatitis B or C positive
- •Norovirus antibody screening titer of > 1:1600
- •Clinically significant findings on history or physical examination
- •Clinically significant history of diseases or treatments that may affect the immune system's function
- •Receipt of systemic corticosteroids for greater than 7 days within the past six months
- •Abnormal screening electrocardiogram (ECG)
- •Clinically significant respiratory disease, endocrine disease, liver disease, renal disease, or neurological disease
- •History of malabsorption or maldigestion disorder, major gastrointestinal (GI) surgery, or any other chronic GI disorders that would interfere with the study
- •Clinically significant abnormalities of the health screening laboratory work
- •Use of antibiotics within 7 days prior to entry into the inpatient isolation facility (Day -1)
- •Any medical illness requiring a new prescription medication or hospitalization during the screening period
- •Temperature ≥38.0°C
- •Diarrhea or vomiting during the 7 days prior to challenge administration
- •Allergy to sodium bicarbonate solution
- •Treatment within the past year for an eating disorder
- •History of alcohol or drug abuse within past 3 years
- •Receipt of any vaccine, licensed or investigational, or any investigational product within 30 days of challenge administration or plan to receive any vaccine or investigational product through the study duration
- •Use of any H2 receptor antagonists or prescription acid suppression medication or over-the-counter (OTC) antacids within 72 hours of investigational product administration (Day 0)
- •Use of prescription and OTC medications containing acetaminophen, aspirin, ibuprofen, and other non-steriodal anti-inflammatory drugs within 48 hours prior to investigational product administration
- •Regular use of laxatives or anti-motility agents
- •Receipt of blood or blood products within the past six months
- •Subjects who are unwilling or unable to cease smoking for the duration of the inpatient stay
- •Any other condition, such as a medical, psychiatric, or social condition or occupational responsibility that, in the judgment of the investigator, would interfere with or serve as a contraindication to the subject's participation in the study or assessment of the investigational product
- •Plan to be living in a confined environment within 3 weeks after receiving the challenge strain
- •Commercial food handlers, day care workers, or health care workers involved in direct patient contact
- •Provide child day care services either in a home or in a nonresidential facility
- •Provide direct care to individuals over 65 years of age, young children (<2 years) at home or with household contacts who are:
- •Immunocompromised
- •Pregnant, or
- •Breast feeding
结局指标
主要结局
Measurement of the number of people who develop symptomatic illness after challenge with Norovirus
时间窗: 1 month after challenge
The number of subjects that become infected, as measured by the number of subjects found to be shedding norovirus in their stool, as well as the number of symptomatic infections (viral shedding in addition to other symptoms such as vomiting, diarrhea, abdominal cramps) will be the primary outcome measure. We will also assess the number of subjects who show at least a 4-fold rise in antibodies against Norovirus (comparing pre-challenge and post-challenge antibody levels).
次要结局
未报告次要终点