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Kashangura, Rufaro, Jullien, Sophie, Garner, Paul 
ORCID: https://orcid.org/0000-0002-0607-6941, Young, Taryn and Johnson, Samuel
(2018)
'MVA85A vaccine to enhance BCG for preventing tuberculosis (Protocol)'. Cochrane Database of Systematic Reviews, Issue 1, CD012915.
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Abstract
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess and summarize the effects of the MVA85A vaccine boosting BCG in humans.
Background
Description of the condition
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis. In 2016, 6.3 million new cases of tuberculosis were reported. Tuberculosis now ranks first, followed by human immunodeficiency virus (HIV), as the leading cause of death from an infectious disease worldwide killing an estimated 1.8 million people in 2016, including 370,000 people living with HIV. Over 95% of these people were living in low- and middle-income countries (WHO 2017).
Tuberculosis can be classed as active when people experience signs or symptoms of tuberculosis or have radiological evidence of it. Tuberculosis can also be classified as latent tuberculosis infection (LTBI) where immunological evidence of previous exposure to M. tuberculosis exists without clinical or radiological evidence of the disease (CDC 2000). Of healthy adults with immunological evidence of previous exposure to M. tuberculosis, the overall lifetime risk of progressing to active disease if not treated for the infection is 5% to 10% (Harries 2006). Often this happens months or years after the initial infection in response to a weakening of the body’s immune system. The probability of developing active disease is higher in HIV-positive, diabetic patients, and young children (Baker 2011; Perez-Velez 2012; Tiemersma 2010). Fifty percent of infants with evidence of LTBI will progress to active disease if untreated (Marais 2004). People with LTBI require early diagnosis and treatment to reduce the pool of active tuberculosis cases. This is particularly important in high-risk groups, such as those co-infected with HIV (Sharma 2012). Tuberculosis can be treated with long courses of multiple antibiotics, but the rise of HIV and spread of multi-drug resistant tuberculosis (MDR-TB) means that tuberculosis is still one of the largest threats to public health worldwide (WHO 2017). Structural determinants such as rapid urbanization of populations and economic inequalities, social determinants such as poverty and poor housing, alongside biological factors such as HIV and drug-resistant strains of tuberculosis play a vital role in the spread of tuberculosis through vulnerable populations (Daftary 2012).
The Bacillus Calmette–Guérin (BCG) vaccine is currently the only available vaccine. Epidemiological studies indicate that it has a protective effect against tuberculosis disease in children, particularly against the more severe forms of the disease such as tuberculosis meningitis or miliary tuberculosis (Roy 2014). The effectiveness of BCG differs greatly depending on location and site of infection. It has consistent protection against tuberculosis meningitis and miliary disease in children but variable protection against pulmonary tuberculosis (Abubakar 2013; Colditz 1995). As a result, despite many areas achieving high coverage of BCG vaccination, the disease remains a problem, and a new tuberculosis vaccine remains an important global research priority (WHO 2017).
Previously it has been impossible to ascertain reliably whether the BCG vaccine protected against active disease or infection with M. tuberculosis. This was due to the tuberculin skin test being unable to distinguish between cases of LTBI and people who had been vaccinated with BCG (Roy 2014). An important development was therefore the development and use of interferon gamma release assays (IGRA), which can distinguish between tuberculosis infection and vaccination. This has allowed researchers to establish that BCG vaccination reduces the risk of Mycobacterium infection in some settings (Eisenhut 2009).
| Item Type: | Article |
|---|---|
| Subjects: | QS Anatomy > QS 4 General works. Classify here works on regional anatomy QV Pharmacology > Anti-Inflammatory Agents. Anti-Infective Agents. Antineoplastic Agents > QV 268 Antitubercular agents. Antitubercular antibiotics WF Respiratory System > Tuberculosis > WF 200 Tuberculosis (General) WF Respiratory System > Tuberculosis > WF 250 Immunological aspects |
| Faculty: Department: | Clinical Sciences & International Health > Clinical Sciences Department |
| Digital Object Identifer (DOI): | https://doi.org/10.1002/14651858.CD012915 |
| Depositing User: | Stacy Murtagh |
| Date Deposited: | 29 Jan 2018 11:30 |
| Last Modified: | 06 Sep 2019 10:16 |
| URI: | https://archive.lstmed.ac.uk/id/eprint/8142 |
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