3. Why a malaria vaccine is required?
When microorganism enter the body, the immune system fight these foreign antigens by production of T or B-lymphocytes that produces antibodies, which effectively neutralize foreign invaders. Human body take several days to produces antibodies, while microorganism attack and multiply in the body and produce serious illness before immune system can fit back, this is a reason behind the vaccine manufacturing and development (CDC, 20175; Sarkander et al., 2016; Clem, 2011). Vaccines play important role in protecting from harmful diseases and characterizes the highest contribution of immunology to human health (Hoffman et al., 2015; Arama and Troye-Blomberg, 2014).
3.1. History of vaccines
In 1796, the Scientist …show more content…
There are 1.2 billion people are at high risk of malaria infection (WHO, 2015). Therefore the implementation and development of a malaria vaccine would constitute a major important discovery for global health (Takashima et al., 2017). Malaria parasite has a complex life cycle because it has a multi-stage life cycle and at each stage, the parasite expresses hundreds of unique antigens. In addition, malaria has a highly complexed genome and sophisticated immune evasion measures (Sack et al., 2017). This complexity makes it difficult to develop a vaccine for malaria parasites (Hoffman et al., 2017). Progress during the last years has been significant, for instance malaria candidate vaccine RTS,S/AS01, is under review by the European Medicines Agency (EMA) for its efficacy, safety and quality. However, much work is in progress for development of malaria vaccines. We are hopeful that anti-malaria vaccines will soon be important tools against malaria (Hoffman et al., …show more content…
Recently developed vaccines
5.1. Targets for malaria vaccine Malaria vaccine have three target stages including pre-erythrocytic stages, erthrocytic or asexual stages, and sexual stages. Pre-erythrocytic vaccines are directed against either the invasive sprorozoite or the early stages of development in the liver. Asexual stage vaccines are directed to kill intra-erythrocytic parasites or prevent invasion of erythrocytes by merozoites. Finally, sexual stage vaccine designed to stop mosquitoes from becoming infected by preventing parasite fertilization in the insect vector (Greenwood and Targett, 2011). (Table 2)
5.2. Erythrocytic-stage malaria vaccine
Since clinical symptoms of malaria result from this stage of parasite development, vaccines are therefore designed to prevent disease and death without preventing infection (Ouattara and Laurens, 2014). In addition to preventing clinical disease, an effective blood-stage vaccine that decreases parasite density may also have a role in reducing malaria transmission (Riley and Stewart, 2013). Antigens expressed on the surface of the merozoite and IEs are the main vaccine candidates which include merozoite surface proteins 1, 2, and 3 (MSP1, MSP2, and MSP3), ring-infected erythrocyte surface antigen (RESA), glutamate-rich protein (GLURP), and apical membrane antigen 1 (AMA1) (Ouattara and Laurens, 2014). The majority of these have been tested in phase I trials. Only small number of vaccines have been tested in phase II field
When microorganism enter the body, the immune system fight these foreign antigens by production of T or B-lymphocytes that produces antibodies, which effectively neutralize foreign invaders. Human body take several days to produces antibodies, while microorganism attack and multiply in the body and produce serious illness before immune system can fit back, this is a reason behind the vaccine manufacturing and development (CDC, 20175; Sarkander et al., 2016; Clem, 2011). Vaccines play important role in protecting from harmful diseases and characterizes the highest contribution of immunology to human health (Hoffman et al., 2015; Arama and Troye-Blomberg, 2014).
3.1. History of vaccines
In 1796, the Scientist …show more content…
There are 1.2 billion people are at high risk of malaria infection (WHO, 2015). Therefore the implementation and development of a malaria vaccine would constitute a major important discovery for global health (Takashima et al., 2017). Malaria parasite has a complex life cycle because it has a multi-stage life cycle and at each stage, the parasite expresses hundreds of unique antigens. In addition, malaria has a highly complexed genome and sophisticated immune evasion measures (Sack et al., 2017). This complexity makes it difficult to develop a vaccine for malaria parasites (Hoffman et al., 2017). Progress during the last years has been significant, for instance malaria candidate vaccine RTS,S/AS01, is under review by the European Medicines Agency (EMA) for its efficacy, safety and quality. However, much work is in progress for development of malaria vaccines. We are hopeful that anti-malaria vaccines will soon be important tools against malaria (Hoffman et al., …show more content…
Recently developed vaccines
5.1. Targets for malaria vaccine Malaria vaccine have three target stages including pre-erythrocytic stages, erthrocytic or asexual stages, and sexual stages. Pre-erythrocytic vaccines are directed against either the invasive sprorozoite or the early stages of development in the liver. Asexual stage vaccines are directed to kill intra-erythrocytic parasites or prevent invasion of erythrocytes by merozoites. Finally, sexual stage vaccine designed to stop mosquitoes from becoming infected by preventing parasite fertilization in the insect vector (Greenwood and Targett, 2011). (Table 2)
5.2. Erythrocytic-stage malaria vaccine
Since clinical symptoms of malaria result from this stage of parasite development, vaccines are therefore designed to prevent disease and death without preventing infection (Ouattara and Laurens, 2014). In addition to preventing clinical disease, an effective blood-stage vaccine that decreases parasite density may also have a role in reducing malaria transmission (Riley and Stewart, 2013). Antigens expressed on the surface of the merozoite and IEs are the main vaccine candidates which include merozoite surface proteins 1, 2, and 3 (MSP1, MSP2, and MSP3), ring-infected erythrocyte surface antigen (RESA), glutamate-rich protein (GLURP), and apical membrane antigen 1 (AMA1) (Ouattara and Laurens, 2014). The majority of these have been tested in phase I trials. Only small number of vaccines have been tested in phase II field