Paratyphoid A fever

评价甲型副伤寒结合疫苗接种人体后对甲型副伤寒病的流行病学保护效力。

Enteric fever is responsible for over 20 million illnesses and 200,000 deaths each year. S. Paratyphi A accounts for a substantial and increasing proportion of these cases, as high as 90% in some regions of Asia. There are currently no vaccines directed against S. Paratyphi A, although there some candidates in preclinical and phase 1 trials. This study is funded by the European Vaccine Initiative and the Bill and Melinda Gates Foundation. Paratyphoid is a human-restricted infection, for which there are currently no small animal models available. In order to further our understanding of the host-pathogen interactions, this study will develop a novel human challenge model in which to investigate this infection, using a recent successful typhoid challenge model as its template.
Healthy subjects to ingest a dose of Salmonella enterica serovar Paratyphi A, strain NVGH308, after drinking a bicarbonate buffer. Intensive follow up over 14 days will establish whether each participant meets clearly defined criteria for diagnosis of paratyphoid infection. Statistical analysis will be performed on this outcome will determine if it consistently gives an attack rate of 60 to 75%. If this is not reached with the first cohort of 20 participants, the dose will be escalated and the process repeated. A maximum of 80 participants will be enrolled. Total follow up will be over the course of one year. Descriptive clinical and laboratory data collected from participant observations, samples of blood, faeces, urine and saliva will allow insights into the disease and the host response. These insights will forward our knowledge of paratyphoid disease and may help discover or develop diagnostic methods.
This study is funded by the European Vaccine Initiative and the Bill and Melinda Gates Foundation. Paratyphoid is a human-restricted infection, for which there are currently no small animal models available. In order to further our understanding of the host-pathogen interactions, this study will develop a novel human challenge model in which to investigate this infection, using a recent successful typhoid challenge model as its template.
Healthy subjects will ingest a dose of Salmonella enterica serovar Paratyphi A, strain NVGH308, after drinking a bicarbonate buffer. Intensive follow up over 14 days will establish whether each participant meets clearly defined criteria for diagnosis of paratyphoid infection. Statistical analysis will be performed on this outcome will determine if it consistently gives an attack rate of 60 to 75%. If this is not reached with the first cohort of 20 participants, the dose will be escalated and the process repeated. A maximum of 80 participants will be enrolled. Total follow up will be over the course of one year. Descriptive clinical and laboratory data collected from participant observations, samples of blood, faeces, urine and saliva will allow insights into the disease and the host response. These insights will forward our knowledge of paratyphoid disease and may help discover or develop diagnostic methods. Anticipating the development of a successful live challenge model through this study, there will be the possibility of evaluating novel paratyphoid vaccines that are currently in early clinical phase testing. This serves an important function because field trials in endemic areas are expensive and time consuming. Speeding up this process using our model will be of great benefit to endemic areas.

观察甲型副伤寒结合疫苗以不同剂量、不同免疫程序接种研究人群后的抗体水平，评价甲型副伤寒结合疫苗适宜的免疫剂量和免疫程序。评价不同剂量甲型副伤寒结合疫苗在研究人群中接种的安全性。评价甲型副伤寒结合疫苗接种后在不同年龄层人群中的免疫原性和安全性。