If there is one thing common to all leading bio-research labs on the planet right now, it is the effort to develop a SARS-CoV-2 vaccine. With more than 100 vaccine contenders in the race, and close to a dozen at the human trial stage, the main problem faced by all is the issue of time. While scientists have always followed protocol and a sequence that leads from pre-clinical animal studies and then several phases of human trials, the urgency of the situation has posed new challenges to the vaccine developers.
Here’s a glance at the three leading COVID-19 vaccine developers:
The Ad5-nCoV vaccine developed by China’s CanSino Biologics
An early trial of this vaccine in more than 100 people reveals that it is able to generate an immune response in those subjected to it. This version of the vaccine uses a weakened version of a common cold virus strain, also known as an adenovirus, to deliver relevant genetic material from the virus causing the pandemic. The adenovirus can infect human cells but does not cause the disease.
The science is that, after this delivery process of the vaccine, the infected person’s immune system will create antibodies that will help in the fight against COVID-19, should the person later be exposed to it.
After reaching milestone results, the vaccine is now set to be on its second phase of trialing that includes 500 participants who will either be given the vaccine or a placebo. Phase two which will be a six-month study will also include persons above the age of 60.
The ChAdOx1 nCoV-19 developed by the University of Oxford:
The ChAdOx1 nCoV-19 is developed from an adenovirus that causes infections in chimpanzees. After phase 1 and over 1000 immunization cases in healthy adults, the vaccine is entering phase 2 of trials and will comprise of 10,260 subjects including older adults between the ages of 56 -59, those above 70, and children aged between 5-12. The vaccine also underwent rapid animal testing, subject to the rhesus macaque model. Depending on the level of virus transmission, it could take up to 6 months from now to develop this vaccine, the company foresees.
The mRNA-1273 developed by the Massachusetts-based Biotech Company Moderna Inc.
An alternative to the traditional vaccines that deliver an inactive real virus to the body, an RNA based vaccine works by carrying molecular instructions into cells and produces the required viral protein inside the human body. The advantage of this type of vaccine is that the manufacturing process is much faster, as the viral protein is created within the body, which means the whole lab production step can be skipped. It is also deemed safer, as the vaccine does not carry the weakened virus at the entry point.
Simply put, the mRNA-1273 vaccine works by stimulating the immune system to fight the virus.
The company has completed stage 1 of its clinical trials which has benefitted the patients. The first stage that included 45 healthy persons was to determine the safety and dosage of the vaccine. Phase 2, to be embarked upon with 600 subjects will be conducted to study the efficacy and side effects of the vaccine.
Notably, this vaccine was the first to be injected into volunteering humans.
With these contenders leading the race to find a vaccine for COVID-19 and with the positive results that have emerged from the initial human trials, experts still think it might take up to a year to arrive at a viable vaccine. Considering the number of years it would usually take to develop the vaccine, this would still be considered a scientific feat.