mRNA Vaccines Effective Against Delta Variant

Source: Reuters

A recent study has confirmed that two doses of mRNA vaccines, such as Pfizer, are highly effective against the deadly delta variant.

The start of the pandemic has led to great discoveries in vaccine technology. One of them being mRNA vaccines. Now, a team of researchers have further established mRNA technology as an effective weapon against rising coronavirus variants.  

The data is mounting that the mRNA vaccines are the solution to the Delta variant. It is also apparent that the second dose of these vaccines is needed to augment the immunity from the first dose, for a person to be resilient to the variant.

Dr. Amesh Adalja, Johns Hopkins Center for Health Security in Baltimore

Traditional vaccines work by introducing a weakened or inactivated form of the virus or bacteria inside our body, triggering an immune response. Instead, mRNA vaccines introduce messenger RNA (mRNA) containing instructions to produce ‘spike protein’. This particular protein is present on the surface of the virus. Once formed in the body, it leads to an immune response that results in the production of antibodies.

Currently, there are two mRNA-based COVID-19 vaccines in use across the world: Pfizer and Moderna. Previous trials have demonstrated a vaccine efficacy of over 90% for both vaccines. Therefore, putting them at the forefront of the fight against coronavirus. Moreover, the World Health Organization (WHO) has listed both under their Emergency Use Listing.

Pfizer Demonstrates 88% Efficacy

The Delta variant, first discovered in India, is now considered the dominant strain across the world. Moreover, its quick spread has raised concerns about whether the current vaccines are effective against the deadly strain. A study published in the New England Journal of Medicine investigated efficacies of Pfizer vaccine and AstraZeneca vaccine against the delta variant and compared it to the original Alpha strain.

According to the results, two doses of Pfizer vaccine demonstrated an 88% efficacy against delta variant; compared to 93.7% effectiveness against alpha variant. On the other hand, two shots of AstraZeneca provided 67% protection against delta variant; compared to 74.5% against alpha variant.

These mRNA vaccines are really exceeding all of our expectations. It’s terrific news that the effectiveness is this high despite these variants.

Dr Kathleen Neuzil, Vaccine Development and Global Health at the University of Maryland School of Medicine

The study noted lower efficacies after a single dose of either vaccine. Thus, supporting the need for two doses in providing maximum protection.


Lopez Bernal, Jamie, et al. “Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant.” New England Journal of Medicine, 2021, doi:10.1056/nejmoa2108891.


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