COVID Transmission and Morbidity in Malawi (COVID-TMM)

马拉维的新冠病毒传播和发病率 (COVID-TMM)

• 批准号: 10467335
• 负责人: James Beeson
• 金额: $ 66.11万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10467335
• 关键词: 2019-nCoV; Acute; Adult; Affect; Africa South of the Sahara; African; Age Distribution; American; Americas; Anemia; Antibodies; Antibody Response; Antibody-mediated protection; Antiviral Response; Attenuated; B-Lymphocytes; COVID-19 mortality; COVID-19 vaccination; COVID-19 vaccine; Cells; Childhood; Chronic; Collaborations; Communicable Diseases; Country; Data; Disease; Disease Progression; Effectiveness; Enrollment; Epidemiology; Europe; Exhibits; Exposure to; Frequencies; Health; Helminthiasis; High Prevalence; Household; Immune; Immunity; Immunization Programs; Immunologics; Impairment; Individual; Infection; Inflammatory; Innate Immune Response; Innate Immune System; Interferon Type I; Interferons; Intestinal parasite; Lead; Longevity; Malaria; Malawi; Malnutrition; Memory B-Lymphocyte; Morbidity - disease rate; Natural Immunity; Parasitic infection; Participant; Pathogenesis; Phenotype; Policies; Population; Predisposition; Regimen; Risk; SARS coronavirus; SARS-CoV-2 B.1.617.2; SARS-CoV-2 immunity; SARS-CoV-2 infection; SARS-CoV-2 transmission; Social Behavior; Symptoms; Testing; Time; Training; Universities; Vaccination; Vaccinee; Vaccines; Viral; Viremia; Virus; Work; adaptive immune response; assault; base; booster vaccine; comorbidity; coronavirus disease; cost effective; cytokine; design; high risk; immune activation; improved; indexing; infection risk; macrophage; malaria infection; malarial anemia; monocyte; mortality; pandemic disease; pathogen; programs; respiratory virus; response; seroconversion; serosurvey; transmission process; vaccination outcome; vaccine hesitancy

PROJECT SUMMARY SARS-CoV-2 transmission was expected to have a devastating impact in sub-Saharan African countries. Instead, morbidity and mortality rates in nearly the whole region are an order of magnitude lower than in Europe and the Americas. To identify what is different requires a better understanding of the underlying immunological substrate of the population, and how these factors affect susceptibility to infection, progression of symptoms, transmission, and responses to SARS-CoV-2 vaccination. These populations are assaulted by many infectious diseases, including malaria. Exposure to these pathogens can produce long-lasting changes in the innate immune system, which may confer decreased susceptibility to heterologous infections. By generating rapid responses to the virus, the innate immune system can decrease the susceptibility to SARS-CoV-2 infection and the risk of progression from infection to disease. On the other hand, malaria infections and helminthiasis can impair the acquisition and longevity of antibody (Ab)- induced immunity through several mechanisms, including tolerogenic innate immune responses. In addition to malaria, other co-morbidities, e.g., anemia and chronic undernutrition, are likely to affect Ab-mediated immunity. We hypothesize that malaria and helminthiasis affect morbidity of SARS-CoV-2 in sub-Saharan Africa. Compared to Western populations, both uninfected and infected-but-asymptomatic subjects will have enhanced innate immune phenotypes. Most infections will be asymptomatic. Once infected, though, malaria, infections with intestinal parasites, anemia, and mild undernutrition will decrease the acquisition and longevity of Ab responses, increasing the risk of re-infection. These comorbidities will also reduce longevity of Ab responses elicited by the Astrazeneca vaccine. To test these hypotheses, we will enroll 200 symptomatic individuals (index cases), their household contacts, and 300 vaccinees. We will assess the specific innate immune phenotypes that differentiate uninfected Malawians from Western controls and whether those responses are protecting Malawians from infection and/or progression of disease. We will follow infected participants and vaccinees for 1.5 years to assess acquisition and longevity of Ab responses and memory B cells. The work will be supported by a platform established on the basis of long-term collaborations with the Ministry of Health and the University of Malawi. As global vaccination campaigns launch, data to optimize vaccination in sub-Saharan countries are urgently needed. Identifying groups at high risk of infection and disease and understanding the susceptibility of the local population will help to define optimal vaccination policies to control transmission. Identifying “hypo- responders” and those whose Ab responses wane more quickly will help to optimize vaccination regimen. In summary, data generated by this study will improve our general understanding of SARS-CoV-2 transmission and pathogenesis and will allow regional vaccination programs to be designed for maximum effectiveness.

项目概要 SARS-CoV-2 的传播预计将对撒哈拉以南非洲国家产生毁灭性影响。 相反，几乎整个地区的发病率和死亡率比欧洲低一个数量级 要确定不同之处，需要更好地了解潜在的免疫学。 人群的基础，以及这些因素如何影响感染的易感性、症状的进展、 传播以及对 SARS-CoV-2 疫苗接种的反应。 这些人群受到许多传染病的侵袭，其中包括疟疾。 病原体可以对先天免疫系统产生持久的变化，这可能会导致先天免疫系统的免疫功能下降。 通过对病毒产生快速反应，先天免疫系统对异源感染的易感性。 可以降低对 SARS-CoV-2 感染的易感性以及从感染进展为疾病的风险。 另一方面，疟疾感染和蠕虫病会损害抗体 (Ab) 的获得和寿命 - 通过多种机制诱导免疫，包括耐受性先天免疫反应。 疟疾、其他合并症，例如贫血和慢性营养不良，可能会影响抗体介导的免疫。 我们发现疟疾和蠕虫病影响撒哈拉以南非洲地区 SARS-CoV-2 的发病率。 与西方人群相比，未感染者和感染但无症状的受试者都会有增强 大多数感染都是无症状的，但一旦感染，就会出现疟疾、感染等症状。 肠道寄生虫、贫血和轻度营养不良会降低抗体反应的获得和寿命， 这些合并症也会增加再次感染的风险。 为了测试这些假设，我们将招募 200 名有症状的个体（指示病例），以及他们的情况。 家庭接触者和 300 种疫苗我们将评估区分的特定先天免疫表型。 来自西方国家的未受感染的马拉维人控制着这些应对措施是否能够保护马拉维人免受感染 我们将跟踪感染的参与者和疫苗 1.5 年以进行评估。 Ab 反应和记忆 B 细胞的获取和寿命这项工作将得到平台的支持。 是在与卫生部和马拉维大学长期合作的基础上建立的。 随着全球疫苗接种运动的启动，用于优化撒哈拉以南非洲国家疫苗接种的数据正在不断涌现。 迫切需要识别感染和疾病的高风险群体并了解其易感性。 当地居民将有助于制定控制传播的最佳疫苗接种政策。 反应者”和抗体反应减弱较快的人将有助于优化疫苗接种方案。 总之，本研究产生的数据将提高我们对 SARS-CoV-2 传播的总体了解 和发病机制，并将允许设计区域疫苗接种计划以实现最大效果。