The school-based Vi polysaccharide vaccination program took place in Karachi, Pakistan. Karachi, with a total population of approximately 16 M (based on 1998 the population census was 9,856,318, with growth rate of 3.56% per annum), is administratively divided into 17 townships among which Gulshan-e-Iqbal and Jamshed towns were selected to pilot the initial typhoid vaccination campaign . Gulshan-e-Iqbal town is geographically divided into 13 Union Councils (UCs) and has a total population of 1.2 M, while Jamshed town has 13 UCs and has a total population of 730,000 individuals . These two townships have a mix of public, private, and religious schools with representation from various socio-demographic strata, which could provide evidence for future expansion of school-based vaccination campaign in other parts of the city and the country. These towns also have the highest number of culture-proven typhoid fever cases as reported through Aga Khan University's laboratory network system (Unpublished data from the Aga Khan University Hospital Clinical Laboratory).
A census of all educational institutions was conducted in the targeted townships. The purpose of inclusion of all institutions was to identify and obtain a comprehensive list of educational establishments where children aged 5-15 years were enrolled. This was considered necessarily since the educational establishments in Pakistan change very frequently from opening, closing, merger and division, and that the government statistics do not capture these changes regularly. In addition, the school census was aimed to provide information on the approximate number of target population for vaccination activity in these educational institutions.
Three types of educational institutions exist in these townships, as well as in Pakistan: government-operated public schools, private schools that charge a tuition fee, and religious schools that may or may not charge a fee. Most religious schools provide formal education; however, some only teach the Quran and basic Islamic teachings.
Public schools are established under the law of the province and are regulated by the provincial Department of Education. A majority of these schools provide education at no cost or charge a very nominal annual fee. These schools are monitored by government authorities at city, provincial, and federal levels.
Private schools in Pakistan are established, controlled, and run by individuals, an organization, or an autonomous body. Such schools are supported by an endowment and tuition fees, and are monitored by the Provincial Ministry of Education through the Directorate of Private School Association.
Religious schools or Madrasahs are educational institutions that provide religious education with or without formal education. These fall under two categories: those controlled and monitored by an Imam of a mosque, any mosque authority, or any religious organization, and which mainly provide religious education, as well as boarding and lodging at no fee to students; and those that may also provide formal school education along with religious education. Such institutions are supported by an endowment and monthly tuition fees from students. They are usually affiliated with school examination boards and also award certificates to graduating students. Financial support for these institutions may also come from the community, private sector, and politically affiliated parties. The schools' administrative procedures are guided by a committee headed by the Imam of the mosque.
Collection and analysis
Health and education authorities at city and provincial levels were contacted through seminars and meetings before the start of field activity in order to provide information on the objectives of the school census, as well as the upcoming vaccination program. Memoranda of Understanding (MoU) were signed among Aga Khan University, Ministries of Education and Health, and Town Administrators regarding collaboration on the upcoming activities. Standard Operating Procedures for the field activity and training materials were also developed prior to the census.
A mapping activity was carried out prior to the census to guide the data collection teams for the school visits. Twenty four people were hired and trained on data collection procedures, project scope, and objectives. Extensive training and mock sessions were also conducted on Personal Digital Assistants (PDA) use. There were three groups, with each group led by a field supervisor, consisting of four teams of two people that visited the schools to collect information.
Information about the schools was collected by visiting each school in the study setting. The data collection teams referred to a list of schools provided by the provincial Ministry of Education and Private School Association. The teams also visited each street of the two townships to ensure that all schools were captured during the data collection activity. Prior to data collection visit, the census teams met with a representative of the educational institution and consent was taken for collection of information related to schools. Once the staff member agreed to provide information, the data collection teams administered a structured questionnaire through PDA to the head of each school or other assigned representative. Information on school fee, enrollment by class, past history of involvement in any vaccination campaign, willingness of parents to participate in a vaccination campaign, and additional information related to vaccines, vaccination, and school health practices were collected.
In addition, respondents were asked about difficulties that may be encountered during initiation of a school-based immunization program in Karachi. The respondents were also asked to comment on factors that may be used effectively to promote vaccine uptake among school-aged children in their respective schools. For both questions, they were asked to choose three factors from a list of five and rank them in order of importance.
Quality check and assurance procedures were adopted to ensure quality of the data. An independent monitoring team visited several schools that were randomly sampled from the school list (5% of schools on the list) to verify the census teams' visits to the schools and the appropriateness and accuracy of information.
The electronic version of the data collection questionnaire was developed using Visual Basic of Microsoft Visual Studio 2008 (Microsoft, WA, US). Data were directly saved as text file in PDA and later uploaded as a database file format using Microsoft FoxPro 7.0 (Microsoft, WA, US). Programs were written in FoxPro to identify and clean up range errors, data inconsistency, or logical errors. Reviews of error listings were performed by the field teams and resolved on real-time basis. Corrections were provided to data management personnel to incorporate in the electronic version of the data set. Progress reports were generated on a daily basis by the data management team and shared with field supervisors.
We performed descriptive analysis to calculate the distribution of various variables of interest. For categorical variables proportions and for continuous variables means along with their respective 95% confidence interval were calculated. Stratified analysis was performed to check the distribution between type of schools i.e. public, private and Madrasah. Similarly, within private schools monthly schools fee was used as another variable for stratified analysis. Inferential statistics were not used as this was beyond the scope of this paper. All analysis was performed in statistical software STATA version 11 (StataCorp LP, TX, US).
The school census, which was a part of the pilot typhoid Vi polysaccharide vaccine introduction project, was approved by the Ethical Review Committee (ERC) at Aga Khan University and by the Institutional Review Board (IRB) at the International Vaccine Institute (IVI).