Booster shots offset some of Omicron immune evasion tactics

Although Omicron subvariants of the SARS-CoV-2 pandemic coronavirus have evolved to evade antibody responses from the primary COVID-19 vaccine series, a new laboratory study suggests current vaccine boosters may elicit sufficient immune protection against severe Omicron-induced COVID-19 disease. The project assessed a comprehensive panel of vaccines available in the United States and around the world, as well as immunity acquired through previous infection.

The international research team was led by the lab of David Veesler, associate professor of biochemistry at the University of Washington School of Medicine in Seattle and an investigator at the Howard Hughes Medical Institute.

The findings are published as an Early Release paper Tuesday, July 19, in Science. The lead authors are John E. Bowen and Amin Addetia, both in the UW Medicine biochemistry department.

“The development of lifesaving vaccines is regarded as one of humanity’s greatest medical and scientific achievements, which is exemplified by COVID-19 vaccines,” the project team noted. The protective immunity generated by the primary vaccine series or prior infection has been severely blunted by Omicron subvariants. A booster dose, regardless of the type of COVID-19 vaccine, brings neutralizing antibodies against all the Omicron subvariants to appreciable levels, this latest study shows

The findings come at a time when the United States government is considering recommending second boosters for adults under age 50, due to rising infection rates and the enhanced transmissibility of Omicron BA.5.

This study’s results are consistent with other research evidence that a third vaccine dose expands existing memory B cells in our bodies specific for the surface protein mediating entry into cells (called the spike protein) of the SARS-CoV-2 pandemic coronavirus, as well as inducing new memory B cells. This leads to production of antibodies with enhanced potency against the Omicron subvariants.

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