“Previous research has shown vaccine-induced antibodies respond to the original strain of SARS-CoV-2 by inhibiting the virus’s ability to bind to angiotensin-converting enzyme 2 [commonly known as ACE2], the receptor on a cell’s surface through which SARS-CoV-2 gains entry,” said Joel Blankson, Professor of medicine at the varsity’s School of Medicine.
“Our study suggests those same antibodies yield less ACE2 inhibition with the Omicron strain, opening the door to a breakthrough Covid-19 infection,” he added.
For the study, published in the Journal of Clinical Investigation Insight, Blankson and team analysed both the humoral (SARS-CoV-2 specific antibodies circulating in the bloodstream and produced by B lymphocytes, or B cells) and cellular (direct attack on the virus by T lymphocytes, or T cells) immune responses in 18 healthy and fully vaccinated people, who experienced breakthrough infections within 14 to 92 days after receiving a Covid vaccine booster.
The humoral and cellular immune responses of those participants with breakthrough infections were compared with those from a control group of 31 participants, ages 21 to 60, who also received Covid vaccinations and boosters, and had no prior infection with SARS-CoV-2.
