Three new studies found that the Pfizer coronavirus vaccine reduced transmission of the virus after just a single dose, The Hill reports.
One study by the UK’s University of Cambridge Hospital, which has not been peer-reviewed, found that a single dose of the vaccine resulted in a fourfold decrease in the number of asymptomatic infections.
“This is great news – the Pfizer vaccine not only provides protection against becoming ill from SARS-CoV-2 but also helps prevent infection, reducing the potential for the virus to be passed on to others,” lead researcher Dr. Mike Weekes said.
The study suggested that people who have been vaccinated for more than 12 days have roughly 70% to 75% protection after just one dose.
“This will be welcome news as we begin to plot a roadmap out of the lockdown, but we have to remember that the vaccine doesn’t give complete protection for everyone. We still need social distancing, masks, hand hygiene and regular testing until the pandemic is under much better control,” Weekes said.
Two more studies back findings:
Two other studies published in The Lancet suggest that a single dose of the Pfizer vaccine is enough to protect people who have already been infected from getting it again.
“This could potentially accelerate vaccine rollout,” one of the studies said. “With increasing variants (UK, South Africa, Brazil), wider coverage without compromising vaccine-induced immunity could help reduce variant emergence.”
Pfizer looking at third dose:
At the same time, Pfizer is reviewing whether a third dose of the vaccine may boost immunity against new variants.
The two-dose vaccine is about 95% effective but the company is studying the effects of a third vaccine on trial participants who received their first doses more than six months ago.
"We believe that the third dose," Pfizer CEO Albert Bourla told NBC News, "will raise the antibody response 10- to 20- fold."
Pfizer is also testing a modified version of the vaccine to see if it works well against the variant found in South Africa.
"Every year, you need to go to get your flu vaccine," Bourla predicted. "It's going to be the same with Covid. In a year, you will have to go and get your annual shot for Covid to be protected."