Vaccine Development against COVID-19: Study from Pre-Clinical Phases to Clinical Trials and Global Use.

As per the World Health Organization (WHO), more than 288 vaccines against COVID-19 are being developed, with an estimated 184 being presently investigated in the pre-clinical phases, while 104 of these vaccine candidates are at various stages of clinical trials. Twelve of these are in the advanced stages of clinical investigation, and promising results in the phase 3 trials have already paved the way for their regulatory approval and subsequent dissemination for global use. Preliminary and interim results of some of these candidate vaccines are being analyzed for public dissemination. Some of these vaccines have already been rolled out to immunize not only the highest risk individuals but also the general population in several countries. Once their safety and efficacy are established, the next limiting step would be their mass manufacturing by the pharmaceutical companies to fulfill the global demand. The challenge of manufacturing billions of doses of high-quality vaccines is under-appreciated at the moment. A massive vaccination drive would be needed to protect people of all ages. The timely and coordinated execution of the vaccination effort would require unprecedented coordination at the national and international levels for generating funds to purchase the required doses of vaccines, fair distribution of doses and managing the mechanics of delivering vaccines throughout the world.