It’s the cold season now in the northern hemisphere, and people tend to stay indoors. It is also the holiday season which means get-togethers will be frequent.
A question that may run in people’s minds is how effective is my Pfizer or the AstraZeneca COVID vaccines?
That’s the question that the research from medRxiv answered. It was recently published on November 25, 2021
The results show that the Pfizer and AstraZeneca vaccines are less protective for the Delta variant than the Alpha variant. The Delta a variant infects >99% of all people now. The Alpha variant was predominant early in the year.
The Delta variants were 4.6 times more transmissible than the Alpha. Less deadly and more transmissible variants tend to persist because they don’t kill their host.
The more dangerous strains like the Alpha get wiped out with treatment or die if it kills its host.
Contacts older than 18 years old were twice more likely to acquire infection than children. Children have smaller sinuses and fewer ACE2 receptors for the virus to adhere to. That’s the reason why COVID-19 is mild in children.
The effectiveness of two doses of Pfizer vaccine against Delta transmission was 31% and 42% for AstraZeneca ChAdOx1 – similar to their efficacy for the Alpha variant.
Pfizer and AstraZeneca are less protective for the Delta variant than for the Alpha variant.
Pfizer’s protection against infection with the Delta variant is only at 24%. The effectivity of Pfizer started at 96% when it was first released and decreased to 84% four months after the second dose.
The findings here are consistent with earlier research showing that the vaccine effectiveness of Pfizer lasts only six months.
AstraZeneca’s protection against Alpha (26%) was higher than for Delta 14%. Again, a decreasing trend of protection. These real-world findings contrast with the “life-long” protection the AstraZeneca vaccine was supposed to provide.
Maybe AstraZeneca thinks that you will have a short life when you get their shot? How did they know that?
Natural immunity against COVID-19 works. Learn more about adaptive immunity against SARS-COV-2 from the following
- High Anti-SARS-CoV-2 Antibodies Among the Unvaccinated in Bangui, Central African Republic
- Protective Antibodies against SARS-CoV-2 are the same in Convalescent and Vaccinated
- Asymptomatic or mild symptomatic COVID-19 elicits effective and long-lasting antibody responses in children and adolescents.
- Can coronaviruses elicit long-lasting immunity?
- 60% may already have Immunity to COVID-19
- Pre-Existing T-Cells Stop COVID-19 Before it Starts
- Harvard: Immunity from mild COVID-19 infection much better than vaccination
- Natural Immunity Protected Tanzania and Zambia from COVID-19
- CD4+ Cross-Reactivity between Seasonal Coronavirus Colds and COVID-19
- Antibodies to COVID-19 can Exist in the Uninfected
Reference:
- ffectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England.
- Covid-19: Pfizer vaccine’s efficacy declined from 96% to 84% four months after a second dose, company reports
BMJ 2021; 374 doi: https://doi.org/10.1136/bmj.n1920 (Published 30 July 2021)
BMJ 2021;374:n1920