A single-shot vaccine for COVID-19

Some human testing begun, with phase 3 trials possible as soon as September.


A group of scientists led by Beth Israel Deaconess Medical Center (BIDMC) immunologist Dan H. Barouch is developing a single-shot vaccine for COVID-19. The vaccine found to be successful in tests on primates.

Tests have shown that the vaccine promotes the creation of protective antibodies.

The vaccine uses a common cold virus, called adenovirus serotype 26 (Ad26), to deliver the SARS-CoV-2 spike protein into host cells, where it stimulates the body to raise immune responses against the coronavirus.

In a past study with 52 rhesus macaques, scientists immunized 32 rhesus macaques with a single dose of one of seven different versions of the Ad26-based vaccine. They gave 20 animals placebo doses as controls.

Vaccinated animals developed neutralizing antibodies against the virus.

Six weeks after immunization, all animals were exposed to SARS-CoV-2. All 20 animals that received the placebos became infected and showed high levels of virus in their lungs and nasal swabs. No virus found in the lungs of six animals that received the optimal vaccine candidate, Ad26.COV2.S and only one animal showed low levels of virus in nasal swabs.

Barouch said“The data demonstrate that a single immunization with Ad26.COV2.S robustly protected rhesus macaques against the SARS-CoV-2 challenge. A single-shot immunization has practical and logistical advantages over a two-shot regimen for global deployment and pandemic control. Still, 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.”

Investigators at BIDMC and other institutions have initiated a first-in-human phase 1/2 clinical trial of the vaccine in healthy volunteers. Kathryn E. Stephenson, assistant professor of medicine at HMS and associate member of the Ragon Institute, is the principal investigator for the trial at BIDMC, which is funded by Janssen Vaccines & Prevention.

Pending clinical trial outcomes, the vaccine is on track to start a phase 3 efficacy trial in 30,000 participants in September.

The results of the tests on the vaccine developed at BIDMC in collaboration with Johnson & Johnson- published in the journal Nature.

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