A single dose of Oxford-AstraZeneca or Pfizer-BioNTech’s Covid-19 vaccine drastically reduces the risk of infection in adults of all ages, British researchers have found.
Two studies released on Friday on inspecting that more than 1.6 million nose and throat swabs taken from 373,402 people between December and April. The data was collected as part of the ongoing Covid-19 Infection Survey, carried out by the University of Oxford, the U.K.’s Office of National Statistics and the U.K.’s Department for Health and Social Care.
Researchers found that 21 days after a single dose of either the Oxford-AstraZeneca or the Pfizer-BioNTech vaccine, new Covid infections both symptomatic and asymptomatic had fallen by 65%.Symptomatic infections fell by 74% three weeks after a single dose of either vaccine, while asymptomatic cases were down by 57%, the data showed.A second vaccine dose reduced the overall infection rate by 70%, with symptomatic Covid infections down by 90% and asymptomatic cases of the virus cut by 49%.
Vaccines had a similar affect in adults of all ages when it came to reducing infection rates, the study found, with their ability to reduce infections also similar regardless of whether or not participants had long-term health conditions. They found that older adults particularly among those over the age of 60 who had never contracted Covid had a lower immune response to a single vaccine dose than those who had been infected with the virus before.The Pfizer-BioNTech vaccine is also being administered in multiple countries, including the United States. The U.S. Centers for Disease Control and Prevention recommends receiving a second dose of the vaccine three weeks after the first.
Antibody responses to two doses of the Pfizer-BioNTech vaccine were high across all age groups, data showed, meaning that older adults were able to reach similar antibody levels to those who had received one vaccine dose after previous Covid infection.