Omicron variants have been increasing immune evasion during the COVID-19 pandemic; a recent laboratory study found evidence that booster shots intensify protection against serious infection of the mutation and its variants.
Booster Immunity Against Omicron
Omicron subvariants of the SARS-Cov-2 pandemic have evolved to evade the antibody response from primary COVID-19 vaccines. A recent laboratory study published in the journal Science, titled "Omicron spike function and neutralizing activity elicited by a comprehensive panel of vaccines." suggests that current booster shots available may elicit sufficient immune protection against severe infection of Omicron variants.
The study assessed a comprehensive panel of vaccines available in the US and worldwide, as well as immunity acquired from the previous infection.
The team of international researchers is led by David Veesler, an associate professor of biochemistry at the University of Washington School of Medicine and an investigator at the Howard Hughes Medical Institute.
The team noted that the development of lifesaving vaccines was regarded as one of the greatest medical and scientific achievements in human history, exemplified by COVID-19 vaccines. Subvariants of Omicron have severely blunted the protective immunity generated by the initial vaccine series or prior infection. A booster dose, regardless of the type of vaccine, brings neutralizing antibodies against all known Omicron subvariants to applicable levels.
The study's findings came when the US government considered recommending second booster doses for adults under 50 due to increasing infection rates and enhanced transmissibility of Omicron variant BA.5.
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COVID Pandemic and Immunity
Results of the study are consistent with various research evidence that the third dose of vaccines expands existing memory B cells in the body specific for the surface protein mediating entry into cells, known as spike proteins, of the SAR-CoV-2 coronavirus, as well as inducing new memory B cells. This leads to the protection of antibodies that have enhanced potency against Omicron and its subvariants, EurekAlert.
Veesler began studying coronavirus infection mechanisms and counteractions of antibodies years before the pandemic began. The team on his latest study consisted of infectious diseases research physicians and scientists from Fred Hutch Cancer Center, UW Medicine, and various research institutes in California, Italy, Argentina, Pakistan, and Switzerland.
As the COVID-19 pandemic continues, genetic variants of the causative virus have emerged that are more transmissible, fitter, and adept at avoiding infection-fighting strategies. The latest concerning variant, Omicron, has greatly diverged from its ancestral SARS-CoV-2 strain consisting of several subvariants, including BA.5, which is predicted to dominate globally soon.
The team first examined the functional impact of the mutations in the spike proteins of Omicron subvariants - the mechanism on the virus that both gives it its appearance and enables it to attach, fuse, and infect cells. Researchers found that the ability of the BA.5 spike to bind with host receptors was more than six times stronger than with the original SARS-CoV-2 strain.
On the other hand, Omicron subvariants were slower at the next major step after receptor binding: fusing with the host cell membrane. As hypothesized by scientists, the stronger binding may help the subvariants compensate for their diminished capacity to fuse with the host.
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