China approved an experimental COVID-19 vaccine for use in the military after early clinical trial data suggested it was safe and stimulated immune responses, but ahead of larger trials that will test whether the vaccine can protect against infections from SARS-CoV-2.
This is the first time that a country has approved a candidate vaccine for military use. The Chinese Central Military Commission made the approval on June 25, which will last a year, according to a report reported by Reuters.
The vaccine, developed by the biotech company CanSino Biologics and the Chinese Army, is a type of vector-based viral vaccine. That means the researchers started with a viral vector, in this case a common strain of adenovirus (type 5), which generally causes mild upper respiratory tract infections. The researchers paralyzed the virus so that it did not replicate in human cells and cause disease. They then engineered the virus to carry a distinctive feature of SARS-CoV-2: the infamous spike protein of the coronavirus, which protrudes from the viral particle and allows the virus to take over human cells.
The idea is that when the harmless vaccine virus is injected into the body, it will essentially present the SARS-CoV-2 spike protein to the immune system, which can then develop anti-SARS-CoV-2 responses. These include antibodies, which are Y-shaped proteins that monitor the body and detect invaders of germs previously found by key characteristics. Once a germ is detected, neutralizing antibodies can gobble up the germ and prevent it from causing an infection.
In a Phase 1 safety trial involving 108 people, the vaccine, called Ad5-nCoV, was shown to be safe and was able to stimulate the production of neutralizing antibodies and other immune responses. However, the study, published in The Lancet, also detected a possible flaw for the vaccine candidate: in people who had been infected with Ad5 in the past, the vaccine did not generate such a strong response to the SARS-CoV spike. -2 protein. This may be because their immune systems quickly recognized the adenovirus and focused their responses on the viral vector, rather than the nefarious peak.
CanSino said it has since completed a larger Phase 2 trial looking at safety and efficacy, but has not yet released the results, according to the South China Morning Post. The document also noted that CanSino has reached an agreement with the Canadian government to carry out Phase 3 trials there. Those trials will look at efficacy and possible side effects in an even larger group of people.
Meanwhile, CanSino declined to say whether members of the Chinese military would have to receive the experimental vaccine or whether it would be optional, according to Reuters.
According to the latest count by the World Health Organization, there are 17 candidates for the COVID-19 vaccine in clinical trials and 132 others in preclinical development. Many vaccines are being developed in China, but with the now limited spread of the coronavirus there, researchers are working to carry out vaccine trials elsewhere, in areas that still have intense transmission.
