According to US media, the vaccine jointly developed by Oxford University and AstraZeneca Pharmaceutical Company in the United Kingdom has limited ability to block the spread of the novel coronavirus, but it can prevent the onset of COVID-19 for most people who have been infected with the virus.
According to Bloomberg News Agency’s website on December 9, as promising vaccine data continue to emerge, an important outstanding question is whether vaccination can slow down the spread of the virus while preventing people from getting sick, which is a key factor for the economic restart.
Oxford and AstraZeneca were the first vaccine developers to publish data on asymptomatic infection rates among vaccinators. The results of peer-reviewed research published by the British medical journal The Lancet on the 8th show that in a large-scale study, the Oxford-AstraZeneca vaccine reduced the spread of the novel coronavirus by about 27%.
The report said that this is far less effective than 70% of the vaccine in preventing symptomatic cases of COVID-19, and even these results are questioned because of their efficacy for elderly vaccinators.
The researchers reportedly tested the COVID-19 infection of more than 6,000 study participants in the United Kingdom every week and found 29 asymptomatic infections in the vaccination group, compared with 40 asymptomatic infections in the control group of roughly the same number.
A small number of people received a half dose first and then a full dose of a second injection. This vaccination method is more effective in responding to asymptomatic transmission, at 59%. The data supports Oxford University’s initial findings that low-dose and then full-dose programs seem to trigger a stronger immune response and prevent 90% of infections, while two full doses are only 4% effective for asymptomatic transmission.
While vaccines that prevent disease rather than the spread of the virus can be widely used and help reduce the number of deaths from COVID-19, experts say, they can cause people to be complacent. Those who have been vaccinated can still spread the virus to other more vulnerable people, including those who have not been vaccinated or cannot be vaccinated for medical reasons.
According to the report, Andrew Pollard, a professor at Oxford University who led the study, called the data “extremely attractive”, but it is too early to draw a precise conclusion. He said researchers are trying to analyze the number of viruses in swabs to determine whether vaccinations have reduced the virus load, which will help curb transmission.
“The ideal vaccine is a vaccine that prevents transmission, so that protects not only those who have been vaccinated, but also those who cannot or have not yet been vaccinated,” he said in an interview.
The report pointed out that other early coronavirus vaccines faced similar problems, including those developed by Pfizer in the United States and German biotechnology companies. The vaccine has been approved in the UK, and the first round of injection began on the 8th. According to a report by FDA staff, the vaccine may not be as effective as preventing asymptomatic cases.
Pfizer CEO Albert Burla said that Pfizer expects to report data on whether its vaccine can stop the spread of the virus in the first quarter of 2021.