pA single dose of the Pfizer-BioNTech coronavirus vaccine reduces the risk of asymptomatic infections, helping to stem transmission, research suggests.brThe UK has approved three coronavirus jabs – Pfizer-BioNTech, AstraZeneca-University of Oxford and Moderna – after studies demonstrated they significantly ward off severe disease.brWith not everyone able to be immunised, or producing a strong immune response as a result of their vaccination, questions lingered as to whether the jabs prevented the infection itself.brAsymptomatic infections are particularly important amid the pandemic, given these individuals do not know to isolate and may unwittingly transmit the coronavirus even when they speak.brTo learn more, medics from the Cambridge University Hospitals NHS Foundation Trust (CUH) swabbed the site's vaccinated and unvaccinated healthcare workers over two weeks.brResults suggest the risk of an asymptomatic infection decreases by four times more than 12 days after a worker received the Pfizer-BioNTech jab.