COVID-19 single injection vaccine protects non-human primates

The development of a safe and effective vaccine is likely to be required to end the COVID-19 pandemic. A group of scientists, led by Deaconess Beth Israel Medical Center (BIDMC) immunologist Dan H. Barouch, MD, Ph.D., now reports that a leading candidate COVID-19 vaccine developed at BIDMC in collaboration with Johnson & Johnson generated Neutralizing antibodies and non-human primates (NHP) strongly protected against SARS-CoV-2, the virus that causes COVID-19. This study builds on the team’s previous results and is published in the journal. Nature.

“This vaccine led to strong protection against SARS-CoV-2 in rhesus macaques and is now being evaluated in humans,” said Barouch, who is Director of the BIDMC Center for Virology and Vaccine Research.

The vaccine uses a common cold virus, called adenovirus serotype 26 (Ad26), to deliver the SARS-CoV-2 tip protein to host cells, where it stimulates the body to boost immune responses against the coronavirus. Barouch has been working on the development of a COVID-19 vaccine since January, when Chinese scientists released the SARS-CoV-2 genome. Barouch’s group, in collaboration with Johnson & Johnson, developed a series of candidate vaccines designed to express different variants of the SARS-CoV-2 tip protein, which is the primary target for neutralizing the antibodies.

Barouch and colleagues conducted a study on 52 NHPs, immunizing 32 adult rhesus macaques with a single dose of one of seven different versions of the Ad26-based vaccine, and administering 20 simulated animal vaccines as placebo controls. All vaccinated animals developed neutralizing antibodies after immunization. Six weeks after immunization, all animals were exposed to SARS-CoV-2. All 20 animals that received the sham vaccine were infected and showed high levels of virus in their lungs and nasal samples. Of the six animals that received the optimal candidate vaccine, Ad26.COV2.S, none showed virus in their lungs, and only one animal showed low levels of virus in nasal swabs.

Furthermore, neutralizing antibody responses correlate with protection, suggesting that this biomarker will be useful in the clinical development of COVID-19 vaccines for use in humans.

“Our data shows that a single immunization with Ad26.COV2.S solidly protected rhesus macaques against the challenge of SARS-CoV-2,” said Barouch, who is also a professor of medicine at Castle William Bosworth School of Medicine. Harvard Medicine, member of the Ragon Institute of MGH, MIT and Harvard, and one of the leaders of the Massachusetts Consortium’s Vaccine Task Force on Pathogen Preparation. “A single-shot vaccine has practical and logistical advantages over a two-injection regimen for global deployment and pandemic control, but a two-shot vaccine will likely be more immunogenic, and therefore both regimens are being evaluated. in clinical trials. We await the results of clinical trials that will determine the safety and immunogenicity, and ultimately the efficacy, of the Ad26.COV2.S vaccine in humans. “

Researchers at Beth Israel Deaconess Medical Center (BIDMC) and other institutions have started a first phase 1/2 human clinical trial of the Ad26.COV2.S vaccine in healthy volunteers. Kathryn E. Stephenson, MD, MPH, is the trial’s principal investigator at BIDMC, which is funded by Janssen Vaccines & Prevention, BV, a pharmaceutical research arm of Johnson & Johnson.

Pending the results of the clinical trials, the Ad26.COV2.S vaccine is on track to start a phase 3 efficacy trial in 30,000 participants in September.