University of Washington Scientists Reveal High Efficiency of COVID-19 RNA Vaccines
Photo: Clodagh Kilcoyne / Reuters
Pfizer / BioNTech and Moderna vaccines are arguably the most effective COVID-19 vaccines developed so far. The results of a study by scientists at the University of Washington, published in the journal Cell, reveal that the effectiveness of RNA vaccines in preventing symptomatic infection is high and reaches 90 percent.
The experiment involved 15 volunteers, each of whom received two doses of RNA vaccine three weeks apart. Scientists removed the germinal centers from their lymph nodes, where actively dividing B-lymphocytes produce antibodies, 21, 28, 35, 60, 110 and 200 days after the first dose.
The BNT162b2 vaccine, developed by the German biotechnology company BioNTech in conjunction with the American Pfizer, enhances the production of antibodies and also stimulates immune memory. The follicular helper T cells, which support the activity of other immune cells in the germinal centers, remain in the body for up to six months after vaccination. When the number of helper T cells begins to decline, protection against coronavirus is provided by long-lived antibody-producing cells and memory B cells.
Scientists have found that many follicular T-helpers respond to that part of the virus that does not undergo mutations and remains practically unchanged even in the omicron variant. The main target of antibodies produced after vaccination is the S-protein, which binds to receptors in human cells. Mutations in the S-protein usually reduce the effectiveness of neutralizing antibodies, but some parts of the S-protein remain unaffected by changes.
The initial antibodies produced in response to infection are not as effective as those produced by mature B cells. T-helpers present the antigen (foreign molecule) of the virus to B-lymphocytes, after which they begin to synthesize antibodies or turn into memory B-cells.
