Data Collection Notes
In February and early March 2003, CBS staff responsible for the survey spent considerable effort in recruiting people with the requisite skills to work as field staff. Most of those recruited were university graduates, and many had experience either with a previous KDHS or similar surveys, such as the Behavioural Surveillance Survey or the DHS-type survey that was conducted in Nairobi slum areas by the African Population and Health Research Centre. CBS then organized a three-week training course from March 17 to April 5, 2003, at the Izaak Walton Inn in Embu.
A total of 146 field personnel were trained as interviewers, supervisors, health workers and data processing staff. Because of the large number involved, trainees were divided into three groups and trained separately on questionnaire administration. They came together in plenary sessions for special lectures. Four trainers were assigned to each group. The trainers were officers of CBS and NCPD as well as staff from ORC Macro. In addition to the 12 main trainers, guest lecturers gave presentations in plenary sessions on specialised topics, such as family planning; Kenya's Program on Integrated Management of Childhood Illnesses; nutrition and anthropometric measurements; HIV/AIDS; and Kenya's VCT programme for HIV/AIDS.
All participants were trained on interviewing techniques and the contents of the KDHS questionnaires. The training was conducted following the standard DHS training procedures, including class presentations, mock interviews, and four written tests. All of the participants were trained on how to complete the Women's Questionnaire and how to take anthropometric measurements.
Late in the second week of training, the health workers were split off from the other three groups to form a fourth group. Staff from KEMRI, CDC/Kenya, and ORC Macro trained the health workers on informed consent procedures, taking blood spots for HIV testing, and procedures for minimising risks in handling blood products (“universal precautions”). Meanwhile, the other trainees practiced interviewing in their local languages.
During the final week, the whole group visited households in two sites close to the training center for practical interviews. Towards the end of the training programme, some trainees were selected as supervisors and field editors. This group was further trained on how to supervise fieldwork and editing of the questionnaires in the field.
Data collection took place over a five-month period, from April 18 to September 15, 2003. Seventeen interviewing teams were involved in the exercise. Each team consisted of one supervisor, one field editor, four female interviewers, one male interviewer, one health worker, and one driver. The Maasaispeaking team and the two Somali-speaking teams had fewer female interviewers. Five senior staff from CBS coordinated and supervised fieldwork activities. ORC Macro participated in field supervision for interviews, weight and height measurements, and blood sample collection.
To ensure that respondents could learn their HIV status, CDC/Kenya (in collaboration with KEMRI and NASCOP) organised a parallel team of two VCT counselors to work with each of the data collection teams (except in Nairobi, where VCT is accessible through many fixed sites). These mobile VCT teams followed the same protocol applied in fixed VCT sites according to the National Guidelines for Voluntary Counselling and Testing for HIV (Ministry of Health, 2003). This includes discussing the clients' reasons for coming for counselling and testing, their risk factors, and implications of test outcomes, followed by anonymous testing for HIV for those requesting the service. A finger prick was performed to collect several drops of blood for simultaneous (parallel) testing performed with two simple, rapid HIV test kits (Abbott Determine HIV 1/2 and Trinity Biotech Uni-Gold); for quality control, a dried blood spot filter paper was collected on every fifth client for testing in the laboratory. During the 15 minutes while the test was developing, prevention counselling was provided. If the two test results were discrepant, a third test (Instascreen) was performed as a “tiebreaker.” Post-test counselling was then provided.
In the field, the team supervisors and counsellors worked with local officials to locate suitable places within or adjacent to the cluster in which the counsellors could provide VCT services that were accessible and allowed privacy for testing and counselling. The plan was for the two VCT counsellors to “leapfrog” each other, with one staying behind for one or two days after the interviewing team left the area and the other moving ahead of the team to set up services in advance. In practice, this was not always possible because of transport logistics problems.
CDC/Kenya also printed a brochure on HIV/AIDS and VCT for the team's health workers to provide all households and survey respondents. Similarly, numbered vouchers were printed and left with eligible respondents. The vouchers were to be given to the mobile VCT teams or the fixed VCT site when the eligible respondents went for VCT. NASCOP and CDC/Kenya also made arrangements with the few fixed VCT sites charging for services, so that they would provide free services to KDHS clients and send the vouchers back to CDC for reimbursement. Finally, although the VCT teams were to give priority to clients presenting the KDHS vouchers, they also accepted any other clients from the sampled communities. Over 10,600 clients, both respondents and other community members, sought and received free VCT services through the KDHS.
In all households selected for the Men's Questionnaire, all eligible women and men who were interviewed were asked to voluntarily provide some drops of blood for HIV testing. The protocol for the blood specimen collection and analysis was based on the anonymous linked protocol developed by the DHS programme and approved by ORC Macro's Institutional Review Board. This protocol was revised and enhanced by KEMRI and CDC. It was reviewed and approved by the Scientific and Ethical Review Committees of KEMRI and by the Institutional Review Board and Director of CDC in Atlanta, Georgia. The protocol allowed for the linking of the HIV results to the sociodemographic data collected in the individual questionnaires, provided that the information that could potentially identify an individual was destroyed before the linking took place. This required that identification codes be deleted from the data file and that the back page of the Household Questionnaire, containing the barcode labels and names of respondents, be destroyed prior to merging the HIV results with the individual data file.
For the purposes of blood sample collection, a health worker was included in each of the 17 field teams. The health workers were recruited with the assistance of the Ministry of Health. To obtain informed consent for taking blood for HIV testing, the health worker explained the procedures, the confidentiality of the data, and the fact that test results could not be traced back to or made available to the subject; the health worker also provided respondents with information about how they could obtain their HIV status through VCT services. If consent was granted, the health worker then collected a dried blood spot (DBS) sample on a filter paper card from a finger prick, using a single-use, spring-loaded, sterile lancet. Each DBS sample was given a barcode label, with a duplicate label attached to the Household Questionnaire on the line showing consent for that respondent. The health worker affixed a third copy of the same barcode label to a Blood Sample Transmittal Form in order to track the blood samples from the field to the laboratory. Filter papers were dried overnight in a plastic drying box, after which the health worker packed them in individual Ziploc bags with desiccant and a humidity indicator card and placed them in a larger Ziploc bag with other blood spots for that particular sample point. Blood samples were periodically collected in the field along with the completed questionnaires and transported to CBS headquarters in Nairobi for logging in, after which they were taken to the CDC laboratory at KEMRI headquarters in Nairobi for HIV testing.
At the laboratory, the DBS samples were each assigned a laboratory number and kept frozen until testing was started in early September. After the samples were allowed to attain room temperature, scissors were used to cut a circle at least 6.3 mm in diameter. The blots were placed in cryo-vials that contained 200 µl of elution buffer and were labeled with the lab number. The vials were left to elute overnight at 4oC, then they were centrifuged at 2,500 rpm for 10 minutes. These eluates were then tested with an Enzygnost Anti-HIV-1/2 Plus enzyme-linked immunosorbent assay (ELISA) test kit (DADE Behring HIV-1/2) for verification purposes. All positive samples and 10 percent of negative samples were then tested with a Vironostika HIV-1 MicroELISA System (Organon Teknika). Finally, 29 discrepant samples were tested by an INN-OLIA HIV confirmation Western blot kit (Innogenetics, Belgium).