A single dose of Pfizer/BioNTech’s Covid-19 vaccine reduces a person’s risk of infection by 72%, a new study has revealed.
According to Public Health England (PHE), the first dose of the Pfizer/BioNTech Covid-19 vaccine "provides high levels of protection against infection and symptomatic disease.”
PHE's Siren Study, which involved healthcare workers aged under 65, found that one dose of the Pfizer/BioNTech Covid-19 vaccine reduced the risk of infection by 72% after three weeks. Two doses of the vaccine reduced the risk of infection by 85%. This high level of protection also includes the B.1.1.7 coronavirus variant first identified in the UK in December.
For the study, health workers were tested for Covid-19 infection every two weeks using PCR tests and twice a week with lateral flow tests. As Dr. Susan Hopkins, strategic response director at PHE, explained, "there was a lot of asymptomatic testing.”
"Overall we are seeing a really strong effect to reducing any infection: asymptomatic and symptomatic," Hopkins said during a press conference held by the UK's Science Media Centre on Monday.
Promising early data has also shown that people who are vaccinated and subsequently catch Covid-19 are far less likely to die of, or be hospitalized with, the virus. For example, people over the age of 80 who were infected after being vaccinated were 41% less likely to be hospitalized with the virus and 57% less likely to die of it.