Which COVID-19 vaccines are in human clinical trials?

In ordinary times, vaccine development, testing and manufacturing is a process that can take several years to complete. In the context of the COVID-19 global pandemic, we are in far from ordinary times. Extreme efforts are underway across the world to create, test and distribute a safe and effective vaccine.

Over 140 vaccines for SARS-CoV-2 are under investigation according to the World Health Organization. As of August 6, there are 26 vaccine candidates in human clinical trials, which are the following:

1. ChAdOx1 nCov-19: Phase I/II,III

ChAdOx1 nCoV-19, a recombinant adenovirus vaccine developed by the University of Oxford, entered human clinical trials back in April in the UK. The Phase I/II trial enrolled > 1000 healthy volunteers and aimed to test the safety and immune response triggered by the vaccine.

On July 20, the results of the Phase I/II trial were published in The Lancet. They demonstrate that the candidate vaccine was able to provoke a T cell response within 14 days of vaccination, in addition to an antibody response within 28 days.

The candidate vaccine recently entered a Phase III trial, where a larger population is to be enrolled, consisting of 10,000 healthy participants in the UK, and 30,000 participants in the US thanks to a collaboration with the pharma company AstraZeneca.

In early June, the Brazilian Health Regulatory Agency approved the inclusion of Brazil in the clinical trials of ChAdOx1 nCov-19, and it is estimated that 2,000 volunteers will be enrolled in the country.

“These encouraging results support further evaluation of this candidate vaccine in our ongoing large scale Phase III programme, that is still needed to assess the ability of the vaccine to protect people from COVID-19.” – Professor Sarah Gilbert, professor of vaccinology at the University of Oxford Jenner Institute.

2. Adenovirus Type 5 Vector (Ad5-nCoV): Phase I,II

Ad5-nCoV, developed by CanSino Biologics Inc. and the Beijing Institute of Biotechnology, is built upon CanSino’s adenovirus-based viral vaccine technology platform, which has been utilized for infectious diseases such as Ebola in the past.

Ad5-nCoV entered human clinical trials in March based on positive preliminary safety data from animal models.

Results from the Phase II trial were published in The Lancet on July 20, and demonstrated that two different doses of the administered vaccine produced significant neutralizing antibody responses against SARS-CoV-2, with no serious adverse reactions documented.

The Chinese research team concluded that the results support testing of the vaccine in a Phase III effectiveness trial in healthy adults.

3. mRNA-1273: Phase I, II, III

mRNA-1273 is an mRNA vaccine developed against SARS-CoV-2 that encodes for a stabilized form of the virus’ spike (S) protein. Developed by Moderna Inc., the vaccine candidate is currently in Phase I and Phase II trials (NCT04283461 and NCT04405076), and recent interim analyses revealed positive results.

The protocol for a Phase III study has been finalized which will enroll approximately 30,000 participants in the US and is expected to be conducted in collaboration with the National Institute of Allergy and Infectious Diseases.

“These positive Phase I data are encouraging and represent an important step forward in the clinical development of mRNA-1273, our vaccine candidate against COVID-19, and we thank the NIH for their ongoing collaboration. The Moderna team continues to focus on starting our Phase III study this month and, if successful, filing a BLA.” – Stéphane Bancel, Chief Executive Officer of Moderna in a press release.

4. CoronaVac: Phase I/II, III

The inactivated SARS-CoV-2 vaccine, CoronaVac, developed by the Chinese company Sinovac Biotech, is heading towards Phase III clinical trials in China and Brazil, the company recently announced.

This is due to positive preliminary results from a Phase I/II trial involving 743 participants, where no severe adverse effects were observed and immune responses were produced (NCT04383574).

“Our phase I/II study shows CoronaVac is safe and can induce an immune response. Concluding our phase I/II clinical studies with these encouraging results is another significant milestone we have achieved in the fight against COVID-19.” – Mr. Weidong Yin, Chairman, President and CEO of Sinovac, in a press release.

You can find an exhaustive list of the current vaccines in development against COVID-19 here.

Source: Technology Networks