Title : Challenges from preclinical to clinical studies on COVID-19 vaccines in developing countries
Abstract:
The rapid development of COVID-19 vaccines marked an unprecedented scientific achievement. However, translating vaccine candidates from preclinical stages to successful clinical implementation posed significant challenges, particularly in developing countries. These challenges span infrastructure limitations, regulatory barriers, funding constraints, population diversity, and ethical considerations.
Since the emergence of SARS-CoV-2 at the end of 2019, candidate vaccines are in clinical and others are currently approved for emergency use in many countries (Inactivated, Sinopharm; Viral-vector, Astrazeneca, and Gamaleya Research Institute; mRNA, Moderna, and BioNTech/Pfizer). The main challenge in this pandemic was the availability to produce an effective vaccine to be distributed to the world’s population in a short time. Herein, we developed a whole virus NRC-VACC-01 inactivated candidate SARS-CoV-2 vaccine and tested its safety and immunogenicity in laboratory animals. In the preclinical studies, we used four experimental animals (mice, rats, guinea pigs, and hamsters). Antibodies were detected as of week three post vaccination and continued up to week ten in the four experimental models. Safety evaluation of NRC-VACC-01 inactivated candidate vaccine in rats revealed that the vaccine was highly tolerable. By studying the effect of booster dose in the immunological profile of vaccinated mice, we observed an increase in neutralizing antibody titers after the booster shot, thus a booster dose was highly recommended after week three or four. Challenge infection of hamsters showed that the vaccinated group had lower morbidity and shedding than the control group. Then we were ready for phase I clinical trial to assess safety in human subjects, but, we had a great challenge as a developing country
