Evolving With the Virus: Repeat COVID-19 Shots Neutralizing Beyond the Expected

The response to an updated vaccine is influenced by previous vaccinations but also produces broadly neutralizing antibodies.
The COVID-19 pandemic has ended, yet the virus responsible continues to circulate, hospitalizing thousands weekly and frequently producing new variants. Due to the virus’s remarkable capacity for mutation and immune evasion, the World Health Organization (WHO) advises yearly updates to COVID-19 vaccines.

However, some scientists worry that the remarkable success of the first COVID-19 vaccines may work against updated versions, undermining the utility of an annual vaccination program. A similar problem plagues the annual flu vaccine campaign; immunity elicited by one year’s flu shots can interfere with immune responses in subsequent years, reducing the vaccines’ effectiveness.