LONDON: Public Health England (PHE) said on Friday Pfizer and AstraZeneca COVID-19 vaccines were effective against symptomatic COVID-19 infection in high risk groups, citing a preprint study based on 1 million vulnerable people.
Overall vaccine effectiveness against symptomatic disease in risk groups was around 60% after one dose of either AstraZeneca or Pfizer-BioNTech with little difference by age, PHE said.
That rises to 81% for AstraZeneca following a second dose in people in risk groups aged 16 to 64, with no data available for Pfizer. Among those over 64, Pfizer was 89% effective and AstraZeneca 80% effective after the second dose, the health agency said.
“This real-world data shows for the first time that most people who are clinically vulnerable to COVID-19 still receive high levels of protection after 2 doses of vaccine,” said Mary Ramsay, Head of Immunisation at PHE.
About AstraZeneca vaccine
Two versions of the vaccine – produced by AstraZeneca-SKBio (Republic of Korea) and the Serum Institute of India – have been listed for emergency use by WHO.
EMA has thoroughly assessed the data on the quality, safety and efficacy of the vaccine and has recommended granting a conditional marketing authorisation for people aged 18 and above.
The Global Advisory Committee on Vaccine Safety, a group of experts that provides independent and authoritative guidance to the WHO on the topic of safe vaccine use, receives and assesses reports of suspected safety events of potentially international impact.
The AZD1222 vaccine against COVID-19 has an efficacy of 63.09% against symptomatic SARS-CoV-2 infection.
Longer dose intervals within the 8 to 12 weeks range are associated with greater vaccine efficacy.
About Pfizer vaccine
What are the ingredients in the Pfizer-BioNTech COVID-19 vaccine?
The ingredients are mRNA, lipids, potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose.
How does an mRNA vaccine work?
mRNA, delivered to your body’s cells by lipid nanoparticles, instructs the cells to generate the spike protein found on the surface of the novel coronavirus that initiates infection. Instructing cells to generate the spike protein spurs an immune response, including generation of antibodies specific to the SARS-CoV-2 spike protein.
mRNA vaccines do not contain any virus particles, meaning that they don’t contain weakened or dead parts of a virus or bacterium.
Do mRNA vaccines change a person’s DNA?
mRNA is a transient carrier of information that does not integrate into human DNA. mRNA does not enter a cell’s nucleus, which is where our DNA is kept.
