These COVID-19 vaccine candidates in late stage clinical trials

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.

In an interview with IANS last week, Adar Poonawalla, CEO, Serum Institute of India (SII), said that as per the arrangement with AstraZeneca, SII will be making one billion doses of Covishield vaccine over the next one year for India and other low-and-middle-income countries (GAVI countries).

The Phase 3 clinical trials are expected to commence in India around August 2020 in which 4,000-5,000 patients are likely to participate.

A Phase 3 clinical trial of Chinese state-owned pharmaceutical company Sinopharm's inactivated Covid-19 vaccine started in Abu Dhabi in the United Arab Emirates, the Abu Dhabi government media office said in July.

The UAE health authorities recently issued a permit for up to 15,000 volunteers to take part in the trials.

Chinese vaccine maker Sinovac in July said it had received approval for starting a phase-3 clinical trial of its COVID-19 vaccine candidate, CoronaVac, in Brazil.

This study will recruit nearly 9,000 healthcare professionals working in COVID-19 specialised facilities in 12 clinical sites located in several states in Brazil.

The New York Times vaccine tracker also includes a Phase-3 trial by Murdoch Children's Research Institute in Australia to evaluate the efficacy of a Bacillus Calmette-Guerin vaccine, originally developed as a protection against tuberculosis, to protect against COVID-19.

While work on more than 165 COVID-19 vaccine candidates has started, 27 vaccines have entered human trials, according to the tracker.

China's military has received approval for using a COVID-19 vaccine jointly developed by its research unit and CanSino Biologics Inc.

The approval for the Recombinant Novel Coronavirus Vaccine (Ad5-nCoV) was granted on June 25, for one year.

The phase-1 and phase-2 clinical trials of the Ad5-nCoV were conducted in China.