A single shot of Pfizer and BioNTech's COVID-19 vaccine reduces the risk of infection by 70%, the first real-world UK data suggests

The first dose of COVID-19 Vaccine from Pfizer BioNTech will be given to nurse Alice Fallago by medical assistant April Massaro on Thursday, 17 December 2020 in Victorville, California, Desert Valley Hospital.

Irfan Khan / Los Angeles Times through the images of Getty

In a UK study, one fire from Pfizer and BioNTech reduced the risk of coronavirus infection by 70%.

Protection of the COVID-19 vaccine increased to 85 percent for those with two shots.

Pfizer's vaccine was shown to work against a mutated variant found in the United Kingdom and the USA, B.1.1.7.

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The two-dose COVID-19 vaccine of Pfizer and BioNTech provides high protection from infection with only one shot, and probably stops people spreading the virus, as the results of a major, real-world survey on Monday show.

"One dose reduces the risk of catching infection by more than 70 percent , rising to 85 percent after the second dose," PHE England said in a press release on Monday.

"This suggests the vaccine may also help to interrupt virus transmission, as you cannot spread the virus if you do not have infection."

The authors of the study said that "significant protection from infection" were launched 10 days after the shot and plateaued 21 days later.

Results showed that Pfizer's vaccine works against the B.1.1.7 coronavirus variant, known in the UK during the period studied, according to the authors.

B.1.1.7, according to the Centers for Disease Control and Prevention, is estimated to have been 30-50 percent more contagious and spread worldwide to 44 US States, including (CDC).

According to CDC, in the US, more than 32,8 million doses of Pfizer's shot have been deployed.

The ongoing PHE SIREN study has followed over 23 000 UK health workers for two months and tested them on COVID-19 every week, regardless of whether they have symptoms.

Two night tests for polymerase chain reaction (PCR), the gold standard and two weekly fast antigen tests were conducted.

The study then analyzed and confirmed PCR over a time span with COVID-19 infection and correlated those immunized with those not.

Researchers have frequently tested people without symptoms infected by the virus who are used as a "a proxy for transmission" - one in three people who are coronavirus has no symptoms but can pass them on without realizing it.

The study is a pre-print study waiting for other experts to examine its methods and conclusions before publishing it in the medical journal of Lancet.

Another study published in Lancet by health workers in Israel on February 18 found that Pfizer's vaccine protects against symptomatic infection 15 to 28 days after the initial dose but does not evaluate asymptomatic transmission.

The SIREN study participants had work ages, mainly white women and three-quarters did not have medical conditions coexisting, so the findings could not be generalized to the general population or older people.

In the press release, PHE stated that early data from routine testing revealed that a single dose of Pfizer's shot had a 57% efficiency to protect people aged over 80, increasing to over 85% with a second dose against the symptomatic COVID-19.

This effect occurred about 3 to 4 weeks after the first dose.

In comparison to SIREN's results, the lower efficacy is likely because the immune system reacts less well to vaccination as we get older.

In those who received a dose of Pfizer-BioNTech vaccine, PHE added, hospitalization and death by COVID-19 were decreased by over 75%.

Similar findings were reported in a study in Scotland on Monday.

The study analyzed the hospitalization rate following immunization and showed that the shot of Pfizer decreased visits to hospital by up to 85 percent four weeks after the first injection.

Head of PHE immunization, Dr. Mary Ramsay.

It said that "strong evidence" was provided that vaccine Pfizer-BioNTech stops people from being infected and also protects them against hospitalization and death.

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