OneResearch BIOMEDICINE NEWSLETTER – As the Omicron variant of COVID-19 becomes increasingly dominant among skyrocketing cases, including in vaccinated individuals, concerns of the variant’s immune escape abilities have grown.
Vaccines provoke important responses in the immune system to prevent disease, including creation of T cells and antibodies specific to the pathogen they introduce.
In the case of mRNA vaccines for COVID-19, genetic code (mRNA) for the spike protein enters our cells, causing them to manufacture spike proteins. Our immune system then recognizes these proteins as foreign to our bodies, promptly destroying them while creating T cells and antibodies that can work against them in the future.
Antibodies and T cells play different roles in the event of an infection. Antibodies work by creating sites that bind to certain parts of a pathogen. As they pertain to mRNA COVID-19 vaccines, the antibodies will bind strongly to the spike protein.
Since the spike protein is what enables SARS-CoV-2 to enter cells, binding antibodies to them will prevent infection …
“Convalescent individuals greatly benefit from vaccination, an observation that is of significant public health importance.”
Results from multiple studies now support a consensus that naturally infected and twice-vaccinated individuals have nonexistent protection against symptomatic infection due to depleted and ineffective neutralizing antibodies.
However, both populations can reattain significant protection against symptomatic infection by receiving initial vaccinations or a booster – though it is still unknown how long this protection will last.
These data indicate that convalescent individuals greatly benefit from vaccination, an observation that is of significant public health importance.
Even though it has become significantly more difficult to prevent symptomatic infection due to the waning quantity and efficacy of neutralizing antibodies in convalescent and vaccinated individuals, T cells have been shown to remain active and still help prevent severe infection.
This is supported by new data that has shown that SARS-CoV-2-specific T cells remain present in the long-term and are still mostly effective against the Omicron variant in convalescent and vaccinated individuals.
“Based on our data, we anticipate that T-cell responses elicited by vaccines and boosters, for example, will continue to help protect against Omicron, as observed for other variants. We believe this presents some positive news in the global fight against Omicron.” – Matthew McKay, University of Melbourne [source]
Well-preserved T cell immunity to Omicron is likely to contribute to protection from severe COVID-19, supporting early clinical observations from South Africa.