A new vaccine designed to specifically create T-cells against Covid produces a better immune response than the alternatives already in use, according to 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.
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 durable’
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 following 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.
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," Pascal Soriot, the chief executive of AstraZeneca, said on Tuesday.
"T-cells do matter, in particular as it relates to the durability of the response, especially in older people."