Hailu, AsratBelete, AntenehTesfai, Sara2021-11-262023-11-062021-11-262023-11-062021http://etd.aau.edu.et/handle/123456789/28982Background: vaccine preventable diseases have been of global concern. Vaccines are the best way for prevention. Studies are showing that there is disparity in efficacy of vaccines, in industrialized and in low-middle income countries. Additionally, vaccine related diseases aresaid to be occurring in recent decades. Africa produces less than one percent of vaccines and depends on imports. It is important to check how many of these imported vaccines have been subjected to clinical trials, to assess efficacy and safety before they are made available to mass consumption. This study is aimed to evaluate the vaccine trials conducted up to the end of 2020 with no start up period limit to inventory the type of trials undertaken in comparison with the vaccines that are in routine use in African countries and to assess vaccine effectiveness in African settings. Methodology: A systematic review and meta-analysis was carried out to assess the vaccine trials conducted in the 54 African countries. Eighteen WHO approved registries, 2 immunization schedule sites and databases were searched. Data were exported to MS excel and RevMan version 5.4 for analysis. Result: The largest vaccine trial for disease prevention purpose was seen for malaria with 119 (21.2%) whereas the lowest was for tetanus with 1 (0.2%) trial. Out of these vaccines, BCG and OPV are given in all African countries, whereas vaccines for; Hepatitis A Influenza (for both pediatric and adult), MenAC, bOPV, deworming, cholera, DTaP, TdIPV and dtaPHibIP are given only in one country each. From the 26 single disease specific vaccine 17 and from 13 combination vaccines 4 multi-disease vaccines was found to have gone through clinical trial which ranges from the lower 1 ( Tetanus) vaccine trial per disease of interest to the highest of 119 (Malaria) vaccine trials in the single disease specific trials. BCG and OPV given in all African countries (100%) attributed to only 55 (15.5 %) and 2 (0.5%) of the trials, respectively, whereas Malaria vaccine which is given only in 3 (5.5%) of African countries attributed to 119 (33.6%) of the trials. In the malaria vaccine trial review, highest efficacy [30%, 95% CI (0.59, 0.84)] was seen against severe malaria in both children and infants. Whereas, the lowest efficacy [20%, 95% CI (0.75, 0.86)] was found to be in 1st episode of malaria in infants. The highest efficacy [67%, 95% CI (0.16, 0.66)] was seen in HIV positive adults and the lowest efficacy [21%, 95% CI (0.44, 1.42)] was seen in HIV positive infants. The highest efficacy [52%, 95% CI (0.37, 0.61)] of the PCV vaccine was seen against 1st episode of IPD, and the lowest efficacy [13%, 95% CI (0.80, 0.96)] was seen against severe Pneumonia in HIV negative individuals. Conclusion: The overall efficacy of the three types of vaccines that are included in this review was found to be low, and no significant SAEs were found across the vaccines. We found no vaccines terminated for futility. Safety data of these studies were mainly acquired from phase 3 trials not phase 4, we couldn’t assess the safety issues identified from outside of a controlled environment i.e., for a long term effect and the issues seen in general populations.en-USVaccine trials, Infectious diseases, Malaria, Influenza, Pneumonia, Phase 3, Phase 4, Efficacy, Safety, Serious adverse events, AfricaThesis