Comparative Study of Two Tetanus Toxoid Vaccination Strategies: Cold Chain Versus Controlled Temperature Chain

Overview

The purpose of this study is to determine the effectiveness, safety and feasibility of a tetanus toxoid (TT) vaccination strategy relying on the maintenance of vaccines in a controlled temperature chain (CTC). The CTC is defined as the storage and transport of vaccines within a temperature range appropriate to the heat stability profile of TT vaccine. In this study vaccines are transported and stored in the cold chain up to district level. From district to beneficiary level vaccines are exposed to ambient temperatures during a limited period of time. In an initial phase, the stability of 3 lots of TT vaccine kept in CTC is determined. For this, the potency, safety, pH and adsorption of vaccines maintained in CTC will be tested in the laboratory and compared to vaccines that have been maintained in cold chain. If all parameters (i.e. potency, safety, pH and adsorption) are above WHO specifications the strategy in CTC will be used. Only if the laboratory results are adequate, villages will be assigned to one of the vaccination strategies. All women between 14 to 49 years of age in the selected villages who fulfill the inclusion criteria will be invited to participate. In order to determine the baseline anti-tetanus protection, TT vaccination history will be collected from all participants using a standardized questionnaire. Women who have already received at least 2 doses of TT vaccine will be excluded from the study. Moreover, blood will be collected from all participants to later verify in laboratory the baseline protection. A first dose of TT vaccine will be given according to the assigned strategy (CTC or cold chain). Four weeks after the 1st vaccination, a second TT vaccine will be given using the same strategy employed for the first dose. Finally, four weeks after the second dose, a blood sample will be collected from all participants who received two doses of vaccine. The serological responses will be compared in the group that received two doses of TT vaccine maintained in cold chain ant the group that received two doses of vaccine maintained in CTC.