The Conversation

Immune interference – why even ‘updated’ vaccines could struggle to keep up with emerging coronavirus strains

Nurse Natalie O’Connor loads syringes with the Moderna COVID-19 vaccine in February 2021. Joseph Prezioso/AFP via Getty ImagesDespite the success and optimism of the new COVID-19 vaccination campaigns being rolled out worldwide, the emergence of new viral strains threatens to undermine their effectiveness. Indeed, South Africa has been forced to rethink its strategy as its initial vaccine of choice failed to provide protection to an emerging, but now dominant, viral variant. Hope is still high that the mRNA-based vaccines licensed in the U.S., with their spectacular efficacy, will continue to provide protection despite impaired targeting of new strains. The jury is still out on viral vector vaccines, like the new Johnson & Johnson vaccine, but early data showing a reduced effectiveness against the South African variant has raised alarms. RNA viruses, like coronaviruses, are known for their ability to mutate. With continued widespread infection, the opportunity for the virus to mutate and evade ongoing vaccination efforts remains high. Many in the scientific community have felt comfortable in the knowledge that mRNA-based vaccines can be quickly modified and redeployed. If the our current vaccines fail, we revaccinate individuals with obsolete immunity against the new strains, and play global whack-a-mole as the virus evolves. But