Goodness Anayochi - when you say 'your focus is on SRs carried out in Africa in the past 8 years I assume you are asking 'Is there a recent SR of studies of the effectiveness of school-based programmes in the control of teenage pregnancy in Africa'.
There has been a recent review of interventions for sexual risk behaviours, which includes pregnancy as an answer.
Shangase, N., Kharsany, A.B.M., Ntombela, N.P. et al. A Systematic Review of Randomized Controlled Trials of School Based Interventions on Sexual Risk Behaviors and Sexually Transmitted Infections Among Young Adolescents in Sub-Saharan Africa. AIDS Behav 25, 3669–3686 (2021). https://doi.org/10.1007/s10461-021-03242-8
Depending on the scope of your interests and the eligibility for that review this may only be a partial answer.