A new study has found that a COVID-19 vaccine candidate is highly effective in protecting rhesus macaque monkeys from the disease.
Developing a safe and effective vaccine is central to stopping the spread of SARS-CoV-2, the virus responsible for COVID-19.
While emergency measures that authorities put in place to promote physical distancing and protect those most at risk have been important in slowing the spread of the virus, given its virulence, the resulting reduction in transmission rates is likely to be temporary.
The continued spikes in novel coronavirus infections throughout the world, many months after the first implementation of emergency measures, seem to confirm this.
Treatments for the disease that the virus causes are also an important part of the equation. They may reduce the severity of COVID-19 if a person does contract the virus or reduce their chances of getting the infection in the first place.
However, reducing the rate of infection sufficiently for societies to return to normal may be challenging if we rely on treatments alone.
Thus, much current research revolves around the search for a vaccine, which would “teach” a person’s immune system how to fight SARS-CoV-2 — in theory, stopping the virus in its tracks.
The development of a vaccine that is both effective and safe across different demographics of the global population can take a considerable amount of time, though.
Fortunately, according to the authors of a recent review article in the journal Frontiers in Pharmacology, “unparalleled data sharing and collaborative team efforts” between global institutions has meant that time estimates for the development of a safe and effective COVID-19 vaccine are down from the usual 10 or more years to about 12–18 months.
Recently, a new COVID-19 vaccine candidate has shown promise, with its developers demonstrating that it is highly effective in protecting rhesus macaque monkeys from developing the disease.
The research, which features in the journal Nature, is an important step in perfecting the vaccine, which researchers will now test in human clinical trials.
Researchers at the Beth Israel Deaconess Medical Center (BIDMC) in Boston, MA, are developing the new vaccine in collaboration with the pharmaceutical corporation Johnson & Johnson.
The team has tested the vaccine on 52 rhesus macaque monkeys to ascertain its potential.
The vaccine uses a common cold virus to transport SARS-CoV-2 proteins into the host cells, where they stimulate an immune response.
The researchers gave 32 of the monkeys a single shot of one of seven initial variations of the vaccine. These included the variation that they had identified as the optimal candidate: Ad26.COV2.S.
They administered a placebo to the remaining 20 monkeys, which acted as a control group.
At 6 weeks after the immunization, the team exposed all of the monkeys to SARS-CoV-2.
All of the control group of monkeys became infected with SARS-CoV-2, with the researchers finding significant amounts of the virus in their lungs and nasal passages.
However, of the six monkeys that received the optimal vaccine variation, none had the virus in their lungs, and only one had the virus in its nasal passage.
According to Dr. Dan Barouch, Director of BIDMC’s Center for Virology and Vaccine Research and a co-author of the current study, “[the] data show that a single immunization with Ad26.COV2.S robustly protected rhesus macaques against SARS-CoV-2 challenge.”
“A single-shot immunization has practical and logistical advantages over a two-shot regimen for global deployment and pandemic control, but a two-shot vaccine will likely be more immunogenic, and thus both regimens are being evaluated in clinical trials. We look forward to the results of the clinical trials that will determine the safety and immunogenicity and, ultimately, the efficacy of the Ad26.COV2.S vaccine in humans.”
– Dr. Dan Barouch
The researchers have started phases I and II of human clinical trials based on these findings. Depending on the outcomes of these trials, they aim to begin phase III trials involving 30,000 participants in September.