It is less than two months to go, and the possibility of a vaccine of the novel coronavirus is not about to become a reality.
This is the prognosis of world-renowned vaccinologist Dr. Melvin Sanicas, who pointed in his Facebook page that a vaccine might not be forthcoming within the year.
Still, he said, ”on a positive note”, 11 vaccine candidates have already reached Phased Three, which is the last clinical trial stage before a vaccine is reviewed by a national regulatory authority and eventually approved for safety, efficacy, or quality.
The frontrunners, according to Sanicas, are Covaxin by BharatBiotech, which is an “inactivated, or non-infectious, form of the coronavirus that can no longer cause disease but can still provoke an immune response”. The vaccine requires two doses that are administered 14 days apart.
Sanicas revealed that the not-yet-peer-reviewed results that were posted last September show that the vaccine produced antibodies in monkeys.
The next is China’s CanSino Biologics’ Ad5nCoV which is a viral vector vaccine, which uses a “weakened version of the adenovirus as a vehicle for introducing the SARS-CoV-2 spike protein to the body”.
Sanicas said initial tests published in scientific journal The Lancet show that the vaccine produces “significant immune responses in the majority of recipients after a single immunisation.”
Another is Gamaleya National Center of Epidemiology and Microbiology’ SputnikV, a “viral vector vaccine that also uses a weakened version of the common cold-causing adenovirus to introduce the SARS-CoV-2 spike protein to the body”.
The vaccine, Sanicas said, uses two strains of adenovirus, and requires a second injection after 21 days to boost the immune response.
Johnson and Johnson’s also has JNJ78436735, which is an adenovector vaccine, “which introduces a piece of DNA from SARS-CoV-2 into the common cold-causing adenovirus that has been genetically changed” so that it cannot replicate in the body.
A study published in Nature showed that the vaccine elicited neutralizing antibodies in monkeys and provided “complete or near-complete” protection with just one dose.
“These create viral proteins that mimic the coronavirus, training the immune system to recognize its presence,” Sanicas said.
Murdoch Children’s Research Institute also has a candidate, the Bacillus Calmette-Guerin.
There is already emerging evidence that the vaccine may boost the immune system as well as help fight off other diseases.
“Researchers are investigating whether these benefits may also extend to SARS-CoV-2, and this trial has reached phase three in Australia,” Sanicas revealed.
The vaccine is administered in two doses, 21 days apart. A 2 September study published in the New England Journal of Medicine revealed that he vaccine is safe and produced coronavirus antibodies “at a higher level than is seen among those who have recovered from COVID-19”.
Initial tests based from the first two phases of the trial show that the vaccine is producing antibodies and T-cell responses specific to the SARS-CoV-2 protein.
The company is targeting a regulatory review before the end of the year—and hopes to supply 1.3 billion doses by the end of 2021, Sanicas said.
The next is Sinopharm’s not-yet-named vaccine, which is an inactivated SARS-CoV-2 vaccine that the company hopes will be accessible to the public before the year ends.
Tests results published in JAMA show that the vaccine “can trigger an antibody response with no serious adverse effects”. The study, however, did not measure T cell-mediated immune responses.
Sinopharm had already selected the United Arab Emirates, Peru, and Bahrain for its Phase Three trials.
Initial results in macaque monkeys, published in Science, revealed that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2.
“Sinovac has also released preprint results of its phase two human trial that likewise showed the vaccine produced antibodies with no severe adverse reactions,” Sanicas added.
Phase three trials for Sinovac are in Brazil, Indonesia and Bangladesh.
“Oxford’s research team has transferred the SARS-CoV-2 spike protein—which helps the coronavirus invade cells—into a weakened version of an adenovirus, which typically causes the common cold,” he said.
When this adenovirus is injected into humans, the hope is that the spike protein will trigger an immune response. Last 8 September, AstraZeneca paused the trials for a safety review due to an adverse reaction in one participant in the U.K.
After an investigation by independent regulators, the trials resumed in the U.K., Brazil, South Africa, and India in September and resumed in the U.S. a month later.