A new peptide-based vaccine designed to specifically create T-cells against COVID produces a better immune response than the alternatives already in use, according to German trial data.
The CoVac-1 jab has been developed and made by academics at the University of Tubingen, in Germany.
The cells form part of the immune response to protect people against infections and often work in tandem with antibodies. However, while antibody levels often decline over time and need boosting, T-cells have the ability to stay in the bloodstream for several years, according to the report in The Telegraph.
Evidence is emerging that T-cell levels from vaccines may be key in conferring long-term protection against COVID, but studying the level of them in a person’s system is difficult.
“The induction of SARS-CoV-2 T-cell immunity is a central goal for vaccine development and of particular importance for patients with congenital or acquired B-cell deficiencies,” the researchers wrote in a paper published in Nature. “The latter comprise cancer patients with disease or treatment-related immunoglobulin deficiency.”
T-cell response ‘is actually more durableʼ
Phase one trial data from 36 people who received the experimental jab early this year showed the vaccine to be safe and capable of producing a robust immune response.
The scientists said the vaccine’s T-cell response “surpassed those detected after SARS-CoV-2 infection as well as after vaccination with approved vaccines”.
Data suggest that the vaccine, a single shot in the stomach, produces 3.5 times as many T-cells as the Pfizer/BioNTech jab and 20 times as many as the AstraZeneca vaccine. “Furthermore, vaccine-induced T-cell responses were unaffected by current SARS-CoV-2 variants of concern,” the scientists said.
Although the study is small, the results are promising because nobody in the trial tested positive for COVID in the three months after their T-cell jab. The team suggested the vaccine would make for an effective complementary vaccine, particularly for the elderly and immunocompromised, alongside the currently approved jabs, reports The Telegraph.
T-cells are becoming of increasing interest to vaccine makers and clinicians as a way to further protect people against disease.
“The antibody response is what drives the immediate reaction or defence of the body when you’re attacked by the virus and the T-cell response takes a little longer to come in but it’s actually more durable, it lasts longer and the body remembers that longer,” said Pascal Soriot, chief executive of AstraZeneca, on Tuesday (23 November).
“T-cells do matter, in particular as it relates to the durability of the response, especially in older people.”
Study details
A COVID-19 peptide vaccine for the induction of SARS-CoV-2 T cell immunity
Jonas S. Heitmann, Tatjana Bilich, Claudia Tandler, Annika Nelde, Yacine Maringer, Maddalena Marconato, Julia Reusch, Simon Jäger, Monika Denk, Marion Richter, Leonard Anton, Lisa Marie Weber, Malte Roerden, Jens Bauer, Jonas Rieth, Marcel Wacker, Sebastian Hörber, Andreas Peter, Christoph Meisner, Imma Fischer, Markus W. Löffler, Julia Karbach, Elke Jäger, Reinhild Klein, Hans-Georg Rammensee, Helmut R. Salih & Juliane S. Walz
Published in Nature on 23 November 2021
Abstract
T cell immunity is central for the control of viral infections. CoVac-1 is a peptide-based vaccine candidate, composed of SARS-CoV-2 T cell epitopes derived from various viral proteins1,2, combined with the Toll-like receptor 1/2 agonist XS15 emulsified in Montanide ISA51 VG, aiming to induce profound SARS-CoV-2 T cell immunity to combat COVID-19.
We conducted a phase I open-label trial, recruiting 36 participants aged 18 to 80 years, who received one single subcutaneous CoVac-1 vaccination. The primary endpoint was safety analysed until day 56. Immunogenicity in terms of CoVac-1-induced T-cell response was analysed as main secondary endpoint until day 28 and in the follow-up until month 3. No serious adverse events and no grade 4 adverse events were observed. Expected local granuloma formation was observed in all study subjects, while systemic reactogenicity was absent or mild. SARS-CoV-2-specific T cell responses targeting multiple vaccine peptides were induced in all study participants, mediated by multifunctional T-helper 1 CD4+ and CD8+ T cells. CoVac-1-induced interferon-γ T cell responses persisted in the follow-up analyses and surpassed those detected after SARS-CoV-2 infection as well as after vaccination with approved vaccines.
Furthermore, vaccine-induced T- cell responses were unaffected by current SARS-CoV-2 variants of concern (VOC). Together, CoVac-1 showed a favourable safety profile and induced broad, potent and VOC-independent T- cell responses, supporting the presently ongoing evaluation in a phase II trial for patients with B cell/antibody deficiency.
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