Covid-19 vaccines developed by Pfizer-BioNTech and Oxford-AstraZeneca offer similar protection against viral infections. This was the result of an analysis of real-world data from vaccine recipients in the UK. The analysis was carried out by Public Health England (PHE), an executive agency of the UK government.
It shows that one dose of the Pfizer BioNTech vaccine is estimated to be 54 percent effective against symptomatic Covid-19 and 53 percent for the Oxford AstraZeneca vaccine.
In other words, a dose of these vaccines provides 54 and 53 percent effectiveness against developing symptomatic Covid-19 when compared to an unvaccinated person.
To better understand the protection of the two vaccines, their effectiveness was also estimated 4 to 13 days after the first dose.
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In that analysis, it was found that Pfizer and AstraZeneca vaccines showed 57 and 58 percent effectiveness against symptomatic Covid-19, respectively.
The analysis also found that completing the two-dose regimen of these vaccines ensured much greater protection against Covid-19.
Source: Public Health England
For subjects who took two doses, the effectiveness was estimated to be 90 percent for the Pfizer BioNTech vaccine and 89 percent for the Oxford AstraZeneca vaccine compared to an unvaccinated person.
However, regarding the effectiveness of two doses of Oxford-AstraZeneca against symptomatic Covid-19, PHE warned that “there is currently little evidence and the results are inconclusive”.
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PHE added that efficacy “decreases slightly” from 10 weeks after the first dose of the Pfizer BioNTech vaccine. However, no such reduction was noted in the case of the Oxford-AstraZeneca vaccine.
Why do data analysis in the real world?
Explaining the rationale for this comparative analysis of the “real world” data for the two Covid-19 vaccines, PHE said that while both had undergone large-scale clinical trials prior to being approved for public use, a “real word” analysis offered better Analysis understanding of the effectiveness of the vaccine.
“It is important to further evaluate the effectiveness of vaccines in the ‘real world’ as this may differ from the effectiveness of clinical trials,” it said.
For this comparative analysis, PHE relied on data from vaccine recipients in the UK. The current evidence comes mainly from older adults, who were among the earliest groups to be vaccinated.
The AstraZeneca vaccine can offer 85-90% effectiveness against symptomatic Covid
That being said, the analysis has also shown that two doses of the Oxford-AstraZeneca Covid-19 vaccine can be 85 to 90 percent effective against symptomatic diseases.
However, PHE warned that there is not enough data on it to be conclusive.
PHE said the preliminary results were the first of their kind in terms of practical effectiveness of two doses of AstraZeneca, but cautioned that the result had “low confidence” in the results and that the results would be inconclusive until further evidence is gathered would.
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“These new data underscore the incredible effects that both doses of vaccine can have, with a second dose of Oxford-AstraZeneca vaccine providing up to 90 percent protection,” said UK Vaccines Minister Nadhim Zahawi.
Efficacy Against Hospital Admission: Pfizer vs. AstraZeneca
In terms of the effectiveness of the two vaccines against hospitalization, PHE has estimated in several studies that the two vaccines are more effective against hospitalization in older adults than in symptomatic cases.
According to the PHE, a dose of the Pfizer BioNTech or Oxford AstraZeneca vaccine provides about 75 to 85 percent effectiveness against hospital stays.
“Two-dose data are currently only available for the Pfizer BioNTech vaccine and indicate approximately 90 to 95 percent efficacy against hospital stays,” said PHE.
Aside from effectiveness against symptomatic Covid-19 and hospitalization, the analysis conducted by PHE shows that the two vaccines themselves offer similar effectiveness against infection, transmission and mortality.
The AstraZeneca vaccine works well as a booster
In a similar development, a study found that the Oxford-AstraZeneca vaccine “works well as a third booster shot”.
Reporting on the development, the Financial Times said“An upcoming study from Oxford University showed that a third dose boosted participants’ antibodies to the coronavirus spike protein.”
According to the report, some scientists have feared that repeated use of the adenovirus vector could prevent the immune system from recognizing the virus’ spike protein.
However, citing unnamed sources familiar with the Oxford study, the Financial Times said the study found that participants’ immune systems “responded to the adenovirus that was used to deliver the protein – but it did far more significant response to the protein ”.
“The antibody response to the booster shot was ‘incredible’ and strong enough to ‘blow almost any variant’,” reports the Financial Times, quoting another person familiar with the study’s results.
The report added that the results of this study “strengthen the case for using the AstraZeneca vaccine as a booster when immunity in vaccine recipients deteriorates over time”. It can also help the person fight new variants of the virus that is causing Covid-19.
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