In the last four months the corona virus pandemic has brought so much despair, despondency, agony and anxiety in its wake that we all yearn to get back to the ‘normal’ life we all once knew, as soon as possible. So much hope has been ignited by the recent announcements made by the large biopharmaceutical companies on vaccine research that we desperately want to believe that all of it is true!
In the quest for the vaccine against Covid-19, four global companies have come out with very encouraging results and are vying with each other for the pole position. The front runner is US- based company Moderna, the only one to publish an interim analysis of the open-label Phase 1 study in New England Journal of Medicine just this last week- resulting in quadrupling of its share prices in the stock market. The research study was conducted at the Kaiser Permanente Washington Health Research Institute in Seattle and the Emory University School of Medicine in Atlanta, starting as early as March this year.
It evaluated a two-dose vaccination schedule of mRNA-1273 across three dose levels (25, 100, 250mcg) in 45 healthy adults (15 volunteers in each dosage group), in the 18-55 years age group. Neutralising antibodies were observed in 100% of the evaluated participants; and the 100mcg dose level was selected for Phase3 (which will recruit 30,000 volunteers with all age ranges and diverse racial groups), the geometric mean titres were above those seen in convalescent sera (of patients who have recovered from the disease) and Th-1 biased CD4 T cell responses were elicited. That is pretty impressive progress in just three months.
Close on the heels of Moderna’s rapid progress, Jenner Institute at University of Oxford, led by Sarah Gilbert has developed its vaccine candidate, ChAdOx1 nCoV-19, in partnership with global biopharmaceutical firm AstraZeneca. This viral vector vaccine is postulated to be better as it stimulates both antibodies and high levels of killer T-cells. Extensive research done by the Jenner Institute on the development of Ebola virus vaccine and Gilbert herself having been deeply involved in MERS vaccine trials, this high-profile corona virus vaccine trial got a head start over its competitors and has already recruited thousands of people in Brazil, South Africa and the United Kingdom. The results of the phase 1 experimental trials (with 1,000 volunteers and in which Gilbert had also recruited her own children, 21-year old triplets all studying biochemistry) have not been published as yet.
CanSino Biologics Inc., a Chinese company has followed a similar approach and uses human adenovirus versus the chimpanzee adenovirus used as a carrier by Jenner Institute but faces higher risk of failure as people could have pre-existing antibodies to the adenovirus and hence, could neutralise the vaccine.
Johnson & Johnson is developing a similar human adenovirus based vaccine, and is said to be starting human trials very soon. The adenovirus based vaccines have an advantage over other candidates as they need to be kept chilled and not frozen, making them easier to distribute.
Pfizer and its French partner BioEnTech, using the same mRNA technology as Moderna, announced an interim report of successfully demonstrating neutralising of antibodies on Day 21 of vaccination. The study is however, not peer reviewed as yet and its validity cannot be completely relied upon.
Another major player in the vaccine race is the Chinese company Sinovac, in collaboration with Brazil’s Butantan has Coronavac, an inactivated virus as vaccine candidate. Coronavac has been granted approval by the Brazilian National Regulatory Agency to conduct phase 3 trials, recruiting 9,000 healthcare professionals from Covid-19 facilities in 12 sites in Brazil. The company promises to share the data of its phase 1& 2 trials in academic portals after approval from its Chinese regulator.
Russia’s Institute of Medical Parasitology, Tropical and Vector- Borne Diseases at Sechenov University successfully completed phase 1 clinical trials earlier this month. Officials made headlines with a sensational statement that the director and other researchers at the Gamelya Institute first tried the vaccine on themselves before starting the human trials on 18 volunteers from the armed forces!
Canada based Medicago is using plants based vaccines by injecting genes into leaves to create protein shells that mimic the viruses. Vaxart is using adenovirus based technology to make an oral tablet vaccine. Medicago and Vaxart are still in phase 1 trials. The Murdoch Children’s Research Institute in Australia is conducting Phase 3 trials for repurposing the BCG (Bacillus Calmette- Guerin) vaccine. Results are still under the wraps.