Six coronavirus vaccines in late stage of clinical trials

Coronavirus Vaccines: Amid the race to develop an effective vaccine against Covid-19 in record time, six candidates have now entered the late stage clinical trial, according to the New York Times vaccine tracker.

The latest entrants in this crucial phase of vaccine development are Moderna and one jointly developed by US-based Pfizer and German biotech firm BioNTech.

Pfizer and BioNTech on Monday announced the start of a Phase 2/3 study of its vaccine candidate BNT162b2.

The Phase 2/3 study will involve up to 30,000 participants between 18 and 85 years of age.

The Phase-3 trial by Moderna will also include 30,000 participants who do not have Covid-19.

The mRNA-1273 vaccine is designed to induce neutralising antibodies directed at a portion of the coronavirus "spike" protein, which the virus uses to bind to and enter human cells. The Phase 3 trial is crucial in the development of a vaccine as it can help answer the question whether it is effective enough to prevent the targeted disease. Earlier, at least four other Covid-19 vaccine candidates entered the phase-3 trials.

The Covid-19 vaccine candidate developed by scientists at the University of Oxford and UK-based global biopharmaceutical company AstraZeneca made early progress and entered into phase trials in South Africa and Brazil.

The results of the Phase 1/2 trials of the vaccine published in The Lancet medical journal last week showed that it produces strong immune responses. The Phase 3 trial of this vaccine will also be conducted in several other countries including India. This vaccine will be called Covishield in India.