Ethics statement
NELSON
The studies involving human participants were reviewed and approved by Nelson Mandela University Human Ethics Committee (ref. no. H18-HEA-HMS-001 and H20-HEA-HMS-001), Eastern Cape Department of Education, Eastern Cape Department of Health Ethics Committee (EC_201804_00), and Northwest and Central Switzerland (ref. no. R-2018-00047 and Req-2020-00430). Written informed consent to participate in this study was provided by the participants’ legal guardian/next of kin, while oral assent was sought from children.