British multinational pharmaceutical company GlaxoSmithKline Plc (GSK) and French pharmaceutical company Sanofi SA announced on 22 February 2021 that they have started a new clinical trial of their protein-based COVID-19 vaccine candidate and aim to reach the final testing stage in the second quarter, Reuters news agency reported on Monday.

In the event that the results are conclusive, the two pharmaceutical companies hope to see the vaccine approved by the fourth quarter after having initially targeted the first half of this year.

This report comes after the companies said in December 2020 that their vaccine would be delayed after clinical trials showed an insufficient immune response in older people.

According to GSK and Sanofi, this new trial will aim at evaluating the safety, tolerability and immune response of the vaccine in 720 healthy adults across the US, Honduras and Panama.

Reportedly, Sanofi and GSK's COVID-19 vaccine candidate uses the same recombinant protein-based technology as one of Sanofi's seasonal influenza vaccines. It will be coupled with an adjuvant, a substance that acts as a booster to the shot, made by GSK.

The study will test two injections given 21 days apart, the companies added.