Two doses of the Pfizer-BioNTech vaccine are 90% effective against COVID-19 hospitalization for at least six months but only 47% effective against infection after that period, according to a new study, says an article published in SKY News.
Evaluated Research
The peer-reviewed analysis of the coronavirus jab, published in The Lancet, also found that reductions in the vaccine’s effectiveness against COVID-19 infection were due to this waning over time rather than the Delta variant escaping protection.
Researchers analyzed the electronic health records of 3,426,957 people 5.4% (184,041) belonged to the infected, and 6.6% (12,130) were hospitalized.
Mechanism of Vaccine
Pfizer-BioNTech and Moderna’s COVID-19 vaccines use mRNA to convey genetic instructions to body cells to manufacture coronavirus antibodies without introducing the virus into the body.
The effectiveness of Pfizer-vaccination BioNTech’s (formally known as BNT162b2) against infection dropped from 88 percent after one month to 47 percent after six months, however, it remained 90 percent effective against hospitalization regardless of the variant the infected person had.
Whole-genome sequencing was performed on 8,911 positive samples from the cohort, and it was discovered that patients infected with the Delta variation accounted for 28% of the positive tests.
Dr. Luis affirms
However, as the Delta variant became the prevalent type of coronavirus in the United States, the proportion of cases ascribed to it rapidly grew from 0.6 percent in April to over 87 percent by July.
Dr. Luis Jodar, chief medical officer of Pfizer Vaccines, said, “Our variant-specific study reveals that the BNT162b2 vaccine is efficacious against all current variations of concern, including Delta.”
“Infections with COVID-19 in patients who have had two doses of the vaccination are most likely attributable to fading immunity rather than Delta or other variations bypassing vaccine protection.”
Writer’s realization
The authors acknowledged that their study had some limitations, including the inability to determine causal links between vaccination and COVID-19 outcomes because the cohort’s vaccination status was not randomized.
They also stated that they had no information on the research population’s adherence to mask recommendations, social interactions, occupation, or disease rates, all of which could influence the risk of developing SARS-CoV-2 infection and being tested for it.
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Source: SKY News
