Background ID93_GLA_LSQ is one of the adjuvanted-recombinant protein vaccines that are in clinical development for the prevention of pulmonary TB. The current composition comprised of two vials, one containing the antigen and one containing an adjuvant, which is‘ bedside mixed’ immediately prior to immunization. Hence, this study developed a strategy for the presentation of the vaccine as a single vial through conjugation and lyophilization. The study also evaluated the field-stability of these samples stored at room temperature in five health facilities in Nigeria.

Methods Lyophilization process was developed to have a single vial of co-mixed(coVL) and conjugate(ConjVL). The physicochemical stability and biological activity stability were evaluated for three months at 4°C and 37°C. The parameters evaluated include cake quality and melting point for the powder, while the reconstituted liposomes were assessed for liposome reformation, particle size, GLA and QS21 concentration and the integrity of ID93. The samples were stored in five health centres to assess the stability of the formulation outside cold chain for nine months.

Results The assessment of the stability parameters for coVL and ConjVL, showed that they were stable at 4°C and 37°C. Moreover, the two formulations maintained their biological activity at the two storage conditions for three months, however, the conjugated formulation still maintained higher memory T cell cytokine recall response in the in vitro whole blood assay as observed with the liquid formulation. The two formulations stored at average daily room temperature of 29.3–30.7°C in five health centres across South -Western geopolitical zone of Nigeria maintained the cake quality and melting points for the nine months with less than 20% reduction in GLA and QS21 across the sites and the particle size growth was also less than 50%.

Conclusion This work presents development of thermostable adjuvant-containing subunit tuberculosis vaccine in developing country.

Funding: This work received funding support from EDCTP