Beyond the spike bullseye
The challenge of developing pan-coronavirus vaccines is dual. “The very best vaccines are highly specific to each strain, and the universal vaccines have to sacrifice effectiveness to get broad coverage. Life is a trade-off.” Dr. Petrovsky told this news organization.
Efforts to broaden vaccine efficacy venture beyond targeting the RBD bullseyes of the spike triplets that festoon the virus. Some projects are focusing on less changeable spike parts that are more alike among less closely related coronaviruses than is the mutation-prone RBD. For example, the peptides that twist into the “stem-helix” portion of the part of the spike that adheres to host cells are the basis of some candidate vaccines now in preclinical studies.
Still other vaccines aren’t spike based at all. French company Osivax, for example, is working on a vaccine that targets the nucleocapsid protein that shields the viral RNA. The hope is that presenting various faces of the pathogen may spark immunity beyond an initial antibody rush and evoke more diverse and lasting T-cell responses.
With the myriad efforts to back up the first generation of COVID-19 vaccines with new ones offering broader protection, it appears that science may have finally learned from history.
“After the SARS outbreak, we lost interest and failed to complete development of a vaccine for use in case of a recurrent outbreak. We must not make the same mistake again,” Dr. Giurgea and colleagues wrote in their Nature article about universal coronavirus vaccines.
A version of this article first appeared on Medscape.com.