A new single-shot vaccine, called CoVac-1 has shown to be safe and provide long-lasting immunity in human trials.
A team at the Germany’s University of Tuebingen has developed a multi-peptide vaccine with the ability to induce long-lasting immunity. Called CoVac-1, the single-dose vaccine provokes an immune response through white blood cells. However, unlike the other COVID-19 vaccines, CoVac-1 relies on T cell immunity. Notably, other vaccines either contain copies of viral mRNA (Pfizer and Moderna vaccine) or a modified viral antigen as in Johnson and Johnson’s vaccine. The CoVac-1 is set apart by the fact that it contains copies of various viral antigens, including from the spike protein, envelope, and membrane.
Normally, when the body encounters a pathogen, the B cells produce antibodies against the foreign antigens. These antibodies target specific pathogens within the body. However, T cells target the whole infected cells and stimulate B cells to produce antibodies. These T cells further act as memory cells, enabling a quick response on countering the same pathogen again. Thus, T cell responses serve to provide long-lasting immunity. Moreover, this secondary immune response is particularly important in patients with B cell deficiencies.
Vaccine Relies on T Cell Immunity
The researchers conducted a phase 1 trial of the new vaccine. They administered the vaccine to 36 participants aged between 18 to 80 years and with no history of COVID infection. The team then assessed the T cell response in the participants. Results of the phase 1 trial are available in the journal Nature.
According to results, 100% of the participants showed a strong T cell response in response to the vaccine; the immune response lasted for three months. Moreover, the team did not find any adverse events to the vaccine.
After success in phase I trials, the team is now conducting phase II trials for the vaccine. The trial will assess the vaccine’s efficacy in people with B cell and antibody deficiency.
Heitmann, J.S., Bilich, T., Tandler, C. et al. A COVID-19 peptide vaccine for the induction of SARS-CoV-2 T cell immunity. Nature (2021). https://doi.org/10.1038/s41586-021-04232-5