The investigation of the dynamics of changes in neutralizing antibody titers against type 5 adenovirus in the context of vaccination against a new coronavirus infection

This research focuses on analyzing the dynamics of neutralizing antibody (nAbs) titers against type 5 adenovirus (Ad5) in the adult population of Russia following vaccination against the novel coronavirus infection with recombinant adenovirus type-5 COVID-19 vaccine (CanSino Biologics, China). The impact of the Ad5 vector on nAb titers was investigated using 302 blood serum samples from individuals who received a single dose of the Ad5-nCoV vector vaccine. The research revealed that 33.8% of adults in Russia had pre-existing anti-Ad5 nAbs before the pandemic. Notably, 40% of vaccinated individuals did not exhibit an increase in nAbs titers upon receiving the Ad5-based vaccine. However, in the group with no or low titers of anti-Ad5 nAbs (1:10–1:40), a significant 8-16-fold increase in nAb titers to Ad5 was observed. •The research revealed that 33.8% of adults in Russia had pre-existing anti-Ad5 nAbs before the pandemic.•40% of vaccinated individuals did not exhibit an increase in nAbs titers upon receiving the Ad5-based vaccine.•A significant 8-16-fold increase in nAb titers to Ad5 was observed in the group with no or low titers of anti-Ad5 nAbs.