Everything You Want to Know About the Pfizer-BioNTech Vaccine Efficacy

        The Pfizer vaccine requires two doses and works by providing your body with instructions on how to make the spike protein unique to this coronavirus. Your immune system processes this information and then builds an immune response, including antibodies.

      Efficacy measures how well a vaccine works in a clinical trial, which is a controlled setting with a defined population.

Real-world effectiveness can be lower because of various reasons, but this is not a reflection on the vaccine. The vaccine was found to reduce transmissions, including those that were asymptomatic, by about 90 percent in a “real-world” setting.

       Clinical trials only show what is going on with the virus at that specific time. By the time the vaccine is given to the general population, the prevalence of the virus might have changed, and new variants might be present. This is another reason why real-world effectiveness might be different from the clinical trial results. This is normal and is to be expected.

        None of the existing vaccines can completely prevent transmission. This is why it is still important to wash your hands regularly, wear a mask, and practice social distancing.

        The Pfizer Covid vaccine is less effective against the Delta variant (also known as B.1.617.2) and that those with two doses would be better protected against the new strain, found a new study in Lancet.

Delta has been declared as Variant of Concern (VOC) by the World Health Organisation (WHO). First detected in India, the Delta variant is now dominant in the UK. It has displaced the B.1.1.7 (Alpha) strain 2 that emerged in the UK with the second Covid wave in late 2020.

Also Read | ‘Pfizer vaccine generates fewer antibodies against Delta variant’ 

The study said that the efficacy of Covid vaccines against B.1.617.2 was unknown so it carried out an initial analysis to track serological responses to vaccination.  

The study was conducted using Pfizer–BioNTech vaccine against five Covid strains, including variants of concerns B.1.617.2 (Delta) and B.1.351 (Beta) first detected in South Africa). The other three variants were: a strain with the original spike sequence (Wild-type); a strain with an Asp614Gly mutation isolated during the first wave of infection in the UK