Animal trials show ‘only mitigation, not immunity’ doubts about the effectiveness of Oxford University vector vaccine

As the outbreak slows, is the world’s long-awaited effective vaccine finally coming? On Wednesday, May 13, Oxford University published an article entitled “ChAdOx1 New Crown Vaccine Prevents Rheous Monkeys From New Coronary Pneumonia” on bioRxiv, a pre-printed website, revealing data from animal trials related to the vaccine. The researchers detected nucleic acids from the neocose virus in all samples of rhesus monkeys exposed to the virus, and the virus load in the Oxford-vaccinated experimental group was no different from that of the unvaccinated control group, the paper said.

In addition, in the follow-up of clinical signs, the researchers found that three of the six rhesus monkeys in the experimental group showed symptoms of shortness of breath in clinical conditions and three were clinically indistinguishable from the control group.

By detecting the viral load of the monkey’s lungs, the researchers also detected the virus nucleic acid in the lung lotion of two rhesus monkeys in the experimental group and three control groups. However, two rhesus monkeys in the control group developed some degree of interstitial pneumonia, and none of the experimental groups did.

According to William Haseltine, a former professor at Harvard Medical School and a leading expert in genomics, the results suggest that the Oxford vaccine does not provide “eliminational immunity” protection for the new coronavirus as the gold standard for vaccines, but can provide partial immunity.

In an op-ed published in Forbes, Haseltine said the test’s nasal secretion sample data showed that all vaccinated rhesus monkeys were infected when attacked by the new coronavirus, and the experimental data did not support the title of the paper.

Jonathan Ball, professor of molecular virology at the University of Nottingham, added that Oxford vaccine data suggested that the vaccine might not stop the virus from spreading between infected people.

It is important that the experimental group and the control group have the same viral load of nasal secretions.

If the same thing happens in humans, then getting the Oxford vaccine will not stop the spread of the virus.

In addition to nasal secretion sample data, Haseltine notes in the article that another disturbing result of the Oxford paper is that the inhibition of viral replication through continuous serum dilution in the study shows that the vaccine’s neutralizing antibody titer is extremely low.

In general, neutralizing antibodies of an effective vaccine can be diluted more than 1000 times and remain active, but in The Oxford vaccine trial, the serum can only be diluted to 4-40 times before neutralizing the antibody is inactive.

Vaccine development continues the race

At present, in the global new crown vaccine research and development of the race track, the major vaccine companies choose different routes, mainly RNA vaccine, DNA vaccine, inactivated vaccine, recombinant carrier vaccine and so on.

Animal trials show 'only mitigation, not immunity' doubts about the effectiveness of Oxford University vector vaccine

Photo: Societe Generale

Among them, the fastest progress, the first to enter phase 2 clinical research is China’s Kangsino biological research and development of adenovirus vector new coronavaccine. Similarly, the Oxford vaccine was developed based on adenovirus vector vaccines and the new coronavirus protoprotein.

However, in Haseltine’s view, the adenovirus vector vaccine does not appear to be as good as the inactivated vaccine, as has been published. But he also suggested that while the Oxford vaccine did not protect animals from infection, it did alleviate the disease.

Haseltine noted that animal trials by Chinese vaccine manufacturer Kexing Bio were better than the results of the Oxford vaccine trial, with no viruses found in the throat, lungs and rectum of the highest dose of inactivated vaccine, and very high levels of neutralizing antibody titration in the serum of the experimental group.

In addition to the Oxford vaccine and the Kering biovaccine, the fastest-growing Moderna vaccine in the U.S. using messenger RNA technology has made good progress in early clinical trials.

The researchers found that at two lower dose levels used in the study, the antibody levels found after a second booster injection were equal to or exceeded those found in patients recovering from the virus.

“This is a good signal that we’ve made antibodies that can stop the virus from replicating,” Stephane Bancel, Moderna’s chief executive, said in an interview on Monday.

As the UK’s leader in the development of new crown vaccines, Oxford University was officially put into clinical trials of a candidate vaccine as early as the end of April.

The British government announced on Sunday that if the new crown vaccine at Oxford University is successful, pharmaceutical company AstraZeneca will quickly begin production, with plans to produce up to 30 million doses of the vaccine for domestic use by September, with an overall production of 100 million doses planned.