Researchers find a new strategy to boost vaccine efficacy amid Omicron spread

Amid the emergence of Omicron cases across the globe, researchers have found that adding a component of a viral protein in the Covid-19 vaccines, can boost their immune response and also provide increased protection against new variants.

The researchers of the University of California, Los Angeles (UCLA) discovered in their findings that using a fragment or component from viral polymerase protein, which is found in SARS-CoV-2 as well as other coronaviruses (SARS, MERS and the common cold) can trigger a more robust immune response from the vaccines.

The study, which has been published in the ‘Cell Reports Journal’ comes at a time when the World Health Organisation (WHO) said that the Omicron variant reduces the efficacy of existing Covid-19 vaccines and is also more transmissible.

“Given the current available data, it is likely that Omicron will outpace the Delta variant where community transmission occurs,” the United Nations health agency said in a technical brief on December 12.

First discovered in South Africa, cases of Omicron Covid-19 variant has now spread to 63 countries, including India. As many as 64 cases of Omicron have been confirmed in India, with West Bengal reporting its first infection a few hours earlier after a 7-year-old boy tested positive. Earlier in the day, Rajasthan and Delhi also reported four cases each of the Covid-19 variant.

According to the researchers of UCLA, their findings will pave the way for preparing a new generation of Covid-19 vaccines that would be able to tackle current variants such as Omicron and Delta, and the ones that may arise in the future.

According to researchers, most Covid-19 vaccines use a component of the spike protein found on the surface of the SARS-CoV-2 to trigger the immune system of the body to produce antibodies. However, newer variants such as Omicron and Delta, which carry mutations to the spike protein, can make them less detectable to the immune cells and antibodies stimulated by vaccination.

Viral polymerases serve as engines that coronaviruses (all types) use to replicate themselves, thereby permitting the infection to spread swiftly. However, unlike spike protein, these proteins are unlikely to change or mutate even as viruses evolve.

Researchers stressed on rare and naturally occurring T cells that are installed with molecular receptors on their surfaces for recognising foreign protein components called ‘antigens’. They said when a T cell encounters an antigen that its receptor recognised, it self-replicates and produces additional immune cells – some of which target and kill infected cells immediately, whereas others remain inside the body for years to fight the same infection should it ever return

To find out if the human immune system has T cell receptors capable of detecting viral polymerase protein, researchers exposed blood samples from healthy individuals (collected prior to the Covid-19 outbreak) to the viral polymerase antigen. The study found that some T cell receptors did, in fact, recognise the polymerase.

The researchers then used a method called ‘CLInt-Seq’ to genetically sequence these T cell receptors. They also engineered T cells to carry these polymerase-targeting receptors, which allowed the research team to study the receptors’ ability to detect and kill SARS-CoV-2 and other coronaviruses.

The team is now conducting more studies to analyse viral polymerase as a potential new component for Covid-19 vaccines in order to find a strategy to increase their protection and long-lasting immune response.

The study is authored by Pavlo Nesterenko, a UCLA graduate student, and Owen Witte, who holds the presidential chair in developmental immunology in the UCLA Department of Microbiology, Immunology and Molecular Genetics. While Pavlo is the first author, Witte holds the corresponding position.