A universal coronavirus vaccine that protects against COVID-19 causing SARS-CoV-2, as well as other coronaviruses such as those causing SARS and MERS, produced promising results in a mouse study.

Multiple SARS-CoV-2 vaccines have gone from development to distribution in many parts of the world, in record time. Indeed, in New York City, over 50% of the adult population has been vaccinated.

But the emergence of SARS (in 2003) and SARS-CoV-2 in 2019 highlights the need to develop universal vaccination strategies against the broader Sarbecovirus subgenus. Now, scientists at the University of North Carolina (UNC) Gillings School of Global Public Health are working to develop a vaccine that protects mice against not only SARS-CoV-2, including the emerging variants, but other coronaviruses as well. This research is published in the journal Science.

To prevent a future coronavirus pandemic, the UNC-Chapel Hill researchers designed a vaccine to provide protection from the current SARS-CoV-2 coronavirus and a group of coronaviruses known to make the jump from animals to humans. Using an mRNA-based approach to create chimeric spike designs—combining regions of spike proteins from different coronaviruses—the team led by David Martinez, PhD, a postdoctoral researcher in the Baric Lab at UNC, demonstrates protection against challenge from five coronaviruses (SARS-CoV, SARS-CoV-2, SARS-CoV-2 B.1.351, bat CoV (Bt-CoV) RsSHC014, and a heterologous Bt-CoV WIV-1) in vulnerable aged mice.

The chimeric spike mRNAs induced high levels of broadly protective neutralizing antibodies against high-risk Sarbecoviruses. This result is in contrast to vaccinating using the mRNA from SARS-CoV-2 alone, which showed a marked reduction in neutralizing titers against heterologous Sarbecoviruses. In addition, a challenge with SARS-CoV and WIV-1 in mice that had been vaccinated with SARS-CoV-2 mRNA alone resulted in breakthrough infections.

However, the chimeric spike mRNA vaccines used in this new study, “efficiently neutralized D614G, mink cluster five, and the UK B.1.1.7., and South African B.1.351 variants of concern.”

The authors write that the multiplexed-chimeric spikes can prevent SARS-like zoonotic coronavirus infections with pandemic potential. “Our findings look bright for the future because they suggest we can design more universal pan coronavirus vaccines to proactively guard against viruses we know are at risk for emerging in humans,” Martinez said. “With this strategy, perhaps we can prevent a SARS-CoV-3.”