Normalcy may “soon” resume on the planet after the outbreak of the novel coronavirus, which has infected about six million people and killed more than 300,000 in four months.
The World Health Organization says 124 potential Covid-19 vaccines are at various stages of development. There are 10 candidate vaccines under clinical evaluation while 115 are in the pre-clinical evaluation stage.
The latest entrant to the global chase for a vaccine is American pharmaceutical giant Merck.
The company said yesterday that it would start developing and making two Covid-19 vaccines and a much-discussed experimental antiviral compound that is in its early clinical trial stage.
Several potential vaccines have reached the clinical trial stage, with some showing little promise. Merck’s vaccine will focus on replicating the viral vector.
This, however, takes longer to develop but is expected to lead to a robust immune response triggered by a single dose.
“Most vaccine projects fail. It is difficult to make a vaccine,” Merck Research Laboratories president Roger Perlmutter told Science magazine.
“If I’m going to start making a vaccine, I’d like to be thoughtful about which platforms have the greatest likelihood of success.”
Among the vaccine candidates with the highest-profile effort is Oxford University’s ChAdOx1 nCoV-19.
PHASE ONE TRIALS
US pharmaceutical giant Johnson & Johnson, through its subsidiary Janssen, has developed AdVac, which uses a genetically modified human adenovirus technology that was used to produce thousands of doses of the Ebola vaccine.
There is also the Chinese firm CanSino Biologics, which has finished phase-one trials of Ad5-nCoV vaccine.
Despite the hopes for a promising vaccine, researchers have called on the world to temper their expectations saying that it can take another 14 to 18 months before the world gets to access a vaccine.
This is because vaccines require a lot of crucial studies, phases of trials to test out potential side-effects to test its safety, feasibility, and cost.
CanSino reported successful results published in a Lancet paper last week is the first Phase 1 Covid-19 vaccine clinical trial anywhere in the world to report full results in a peer-reviewed paper, with 108 healthy adults all showing an immune response to the adenovirus vector vaccine.
But the scientists registered a stumbling block. Because the adenovirus (which causes common cold symptoms) is already widespread in people, some of the volunteers in the trial had already been naturally infected with it, dampening their immune response.
For Oxford’s chimp adenovirus vaccine, the team of researchers who published a preprint paper two weeks ago showing that ChAdOx1 prevented rhesus macaques monkeys from getting pneumonia when infected with SARS-CoV-19 also said that the trials indicated that the vaccinated monkeys still became infected, and nose swabs showed the same amounts of virus in samples taken from both vaccinated and non-vaccinated animals.
PHASE 2 TRIALS
This means in theory that vaccinated people could still be infectious even if they don’t actually get symptoms of the disease.
As humanity holds onto hope, science continues with the race for a cure with CanSino proceeding to Phase 2 trials with a six-month study of 500 adults in Wuhan.
The 10 candidate vaccines in clinical evaluation:
1. ChAdOx1-S –University of Oxforc/AstraZeneca
2. Adenovirus Type 5 ((Ad5-nCoV)) – CanSino Biological Inc./Beijing Institute of Biotechnology
3. LNP-encapsulated mRNA –Moderna/NIAID, U.S
4. Inactivated COVID-19 vaccine – Wuhan Institute of Biological Products/Sinopharm, China
5. Inactivated COVID-19 vaccine – Beijing Institute of Biological Products/Sinopharm, China
6. Formalin-inactivated and alum-adjuvanted (Inactivated+alum) –Sinovac, China
7. NVX-CoV2373 with Matrix-M adjuvant–Novavax, Maryland, US-based
8. 3 LNP-mRNAs – USA (Pfizer), Europe, and China (Fosun Pharma).
9. Inactivated COVID-19 vaccine –Institute of Medical Biology, Chinese Academy of Sciences
10. INO-4800 (DNA Plasmid vaccine with electroporation) – Inovio Pharmaceuticals, U.S Biotech company
Source: WHO DRAFT landscape of COVID-19 candidate vaccines as of May 27, 2020.