Two research studies published in Science today affirmatively answer critical questions about the role of antibodies against COVID-19 and validate the criteria used to select the vaccine candidate in development by Janssen Pharmaceutical Companies of Johnson & Johnson. The results provide further confidence in the potential of a vaccine to protect against COVID-19.
While these studies do not include Janssen’s lead COVID-19 vaccine candidate, the data have helped the Company in the vaccine selection process.
“These two studies contribute to the increased understanding of SARS-CoV-2 and give us predictive models to test vaccine candidates. Together with Janssen we are now evaluating their lead COVID-19 vaccine candidate within this model and believe that this study design has the potential to give us a first indication of the future efficacy of this vaccine candidate,” Dr. Dan Barouch, M.D., Ph.D., Director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Hospital (BIDMC) and the Ragon Institute stated.
“The data from these studies are very encouraging, as we know adenovectors are substantially more immunogenic than the DNA constructs. We therefore anticipate that the levels of protection with our lead vaccine candidate will be higher than for the DNA constructs seen in these studies and expect results to be available by mid-June,” said Johan Van Hoof, M.D., Global Therapeutic Area Head, Vaccines, Janssen Pharmaceutica NV.
In these animal studies, prototype vaccine constructs were used. The studies, led by Dr. Dan Barouch, and others including Janssen, sought to answer critical questions about COVID-19 infection and prevention:
- Do antibodies developed against the coronavirus spike protein during infection protect against future infection?
- Does the level of neutralizing antibodies against the virus directly correlate with the level of protection?
- Can these protective antibodies be elicited by a vaccine?
In one study (Chandrashekar, et al), the results demonstrated that non-human primates exposed to SARS-CoV-2 infection showed signs of active viral replication and cleared the virus over time. Re-exposed to a second dose of SARS-CoV-2 the animals were protected from reinfection which correlated with the presence of SAR-CoV-2 neutralizing antibodies.
The second study, (Yu, et al) demonstrated that when exposed to a DNA vaccine prototype, non-human primates developed a significant level of protection against SARS-CoV-2 replication in the lung upon challenge with the virus. It also clearly showed that, the different prototype DNA vaccine constructs generated different levels of antibodies and higher levels of antibodies correlated with higher levels of protection.
The studies by Chandrashekar, et al, and Yu et al, demonstrate that levels of neutralizing antibodies directed against the SARS-CoV-2 spike protein correlate with a reduction in SARS-CoV-2 replication upon challenge with the virus. They demonstrate that we have now established a non-human primate challenge model which can be used to do an initial evaluation of the potency of COVID-19 vaccine candidates.
Janssen is pursuing the development of a non-replicating viral-vector vaccine, which contains a piece of DNA that codes for the coronavirus "spike". The vaccine leverages Janssen’s AdVac® and PER.C6® vaccine technologies which have been studied in more than 70,000 people and provide the ability to rapidly upscale production.
The data in these studies are not indicative of the data for the vaccine candidate in development by the Janssen Pharmaceutical Companies of Johnson & Johnson.
Janssen announced its lead vaccine candidate (and two back-ups) on March 30. Data for these vaccine candidates are not included in these publications. We expect to have non-human primate data for our lead vaccine candidate in the very near future. We anticipate beginning Phase 1 human clinical studies by September 2020 and anticipate the first batches of a COVID-19 vaccine to be available for emergency use in early 2021.
Chandrashekar et al. 2002. Science. SARS-COV-2 Infection Protects Against Re-challenge in Rhesus Macaques. May 2020.
Yu et al. Science. DNA Vaccine Protection Against SARS-COV-2 in Rhesus Macaques. May 2020.