The two-dose regimen of Pfizer-BioNTech vaccines reduced asymptomatic infection, finds a study.The study, led by St. Jude Children's Research Hospital showed that vaccination reduced the risk of asymptomatic infections by 72 per cent.Overall vaccinations reduced the risk of asymptomatic and symptomatic SARS-CoV-2 infection by 79 per cent in vaccinated people compared with the unvaccinated individuals.Protection was even greater for people who completed two doses. A week or more after receiving the second dose, vaccinated individuals were 96 per cent less likely than unvaccinated people to become infected with SARS-CoV-2.When researchers looked just at asymptomatic infections, vaccination reduced the risk by 90 per cent, according to a research letter that appears in the Journal of the American Medical Association."While further research is needed, by preventing infections, including in people who have no symptoms, there is a high possibility that vaccination will decrease transmission of SARS-CoV-2," said Diego Hijano, from the St. Jude Department of Infectious Diseases.The study involved 5,217 St. Jude employees who were eligible under Tennessee state guidelines for vaccination between December 17, 2020, and March 20, 2021.