Scientists could be about to top the achievement of producing a COVID-19 vaccine in less than a year: a universal vaccine capable of protecting people against not just COVID-19, but all coronavirus-related disease is now firmly in their sights.
The virus that causes COVID-19 is the third coronavirus to trigger a major international public health crisis in less than two decades, following SARS in 2003 and then MERS in 2009. As such coronaviruses spill over from contact between animals and humans, scientists predict that further pandemics from other coronaviruses are highly likely.
The hunt for a universal vaccine began in early 2020, when serum from people who had been infected with SARS-CoV during the 2003 SARS outbreak was found to contain antibodies that could neutralise the spike protein of the SARS-CoV-2 virus that causes COVID-19. Similarly, serum from people who had been infected with COVID-19 could neutralise both SARS-CoV and MERS.
By April of this year, the first human trials of a vaccine with the potential to protect against a range of coronaviruses began, and since then other potential vaccines have proved to be effective in primates.
One of the greatest achievements in the last year has been the development of mRNA vaccines such as the Pfizer and Moderna vaccines after years of research. This ‘plug-and-play’ vaccine technology allows for the mRNA that codes for the pathogenic protein to be swapped out for the code for a different protein that will confer protection against other viruses or strains.
The team exploited the segmented nature of the spike protein. Current mRNA vaccines against COVID-19 contain an mRNA strand with instructions to make an entire spike protein. However, Martinez and team made four different mRNAs, each with segments from different coronavirus spikes – from the SARS virus, the COVID-19 virus, and two bat coronaviruses that can infect humans but haven’t caused epidemics – yet.
The vaccine showed promising signs of being effective in mice against various coronaviruses including the SARS, COVID-19, MERS and bat coronaviruses, as well as variants of COVID-19, such as the Delta variant.
As with the first-generation COVID-19 vaccines, the simultaneous development of many potential vaccines is beneficial as there are many hurdles between the initial excitement of pre-clinical success and having a licensed vaccine that has been shown to be safe and effective for use in people.
Hedging all bets is a wise idea. As Martinez says: “With this strategy, perhaps we can prevent a SARS-CoV-3 pandemic.”