Study shows Pfizer and BioNTech’s COVID-19 vaccine produced most antibodies

Out of the four vaccines compared, the Pfizer-BioNtech shot revealed the greatest immune response.

A study revealed people who received Sinopharm's vaccination may be more susceptible to a breakthrough infection than those who received Pfizer-BioNTech’s COVID-19 shot, which produced the greatest immune response among four vaccinations examined. Each of the four vaccine groups had different levels of protective antibodies to the part of the coronavirus that SARS-CoV-2 uses to infect human cells. The Sinopharm and Sputnik V vaccines stimulated "quite low" antibody concentrations, whereas the AstraZeneca vaccine stimulated intermediate levels, and the Pfizer-BioNTech vaccination stimulated the greatest levels. The causes for the differences in immune responses between vaccination types are a hot topic for research. The factors include the amount of active ingredient in each dose and the time interval between doses as stated by authors of the paper published.

The results could have been influenced by how the vaccines were administered. According to the state-run Russian Direct Investment Fund, which backed Sputnik V's development and is in charge of its international roll-out, the study comparisons were flawed, with more time elapsed between administration of the Sputnik V shot and antibody measurements than with the other vaccines. Adding, participants who received the Sputnik V shot were also 10 years older than those who received the other shots. The study was conducted in Mongolia in July among 196 fully immunized people, with all four doses administered – a rare occurrence. The findings suggested that people who received Sinopharm vaccinations, which represented 89.2 % of vaccinated adults in Mongolia at the time would be vulnerable to breakthrough infections, according to the authors.