For years, researchers have dreamt of having one vaccine that could defend against all variants of coronaviruses. Now, according to a new study, we are one step closer to it. 

Researchers from Northwestern Medicine discovered that people with immunity to one type of coronavirus, either because of vaccination or because of natural infection, tend to have immunity against other similar coronaviruses. This is a bigger deal than it sounds. The new findings, the researchers argue, “provide a rationale for universal coronavirus vaccines.”  

Coronaviruses have recently garnered attention due to their potential to cause pandemics — see current events. However, coronaviruses aren’t new — they’re a large family of viruses that cause upper-respiratory tract illnesses. Seven of them have been identified in humans so far, four of them being less problematic, while the other three are known to cause more severe illness, even death. These are the Severe Acute Respiratory Syndrome 1 Coronavirus (SARS-CoV-1), Middle Eastern Respiratory Syndrome Coronavirus (MERS), and now, Severe Acute Respiratory Syndrome 2 Coronavirus (SARS-CoV-2). 

Most coronaviruses circulate among animals but sometimes, they can jump to humans, which is when they tend to become very dangerous. In less than 20 years, there have been outbreaks from the three above-mentioned viruses.

Various vaccines have shown efficacy at preventing Covid-19, helping to drive down the number of infections and deaths very significantly — this is what’s gonna help us get through this pandemic. But whether these also protect against other coronaviruses has so far remained unknown. Now, with the new study, we could be a step closer to having one vaccine for every coronavirus family and preventing future pandemics. 

Understanding coronaviruses

In their study, the researchers found that plasma from patients vaccinated against SARS-CoV-2 produced antibodies that were cross-reactive, meaning potentially providing protection, against other coronaviruses – including SARS-CoV-1 and the common cold coronavirus (HCoV-OC43). This correspondence also appeared in other animals in the study.

Mice vaccinated with a SARS-CoV-1 vaccine generated immune responses that protected them against SARS-CoV-2. At the same time, mice immunized with Covid-19 vaccines and then exposed to HCoV-OC43 were also partially protected against it. This was because SARS-CoV-1 and SARS-CoV-2 are genetically similar, while the common cold coronavirus is more divergent. 

There are three main species of coronaviruses that cause diseases in people: sarbecorivurses, including SARS-CoV2, merbecoviruses, responsible for MERS, and sarbecoviruses, including SARS-CoV-1. Each is so unique that it’s unlikely a single vaccine would fight the three groups. But what we could have is one vaccine effective for every species within each family. 

“Until our study, what hasn’t been clear is if you get exposed to one coronavirus, could you have cross-protection across other coronaviruses? And we showed that is the case,” lead author Pabo Penaloza-MacMaster from Northwestern Medicine said in a statement. “Our study helps us re-evaluate the concept of a universal coronavirus vaccine.”

Of course, whether or not the same mice responses carry out in humans remains to be seen. Oftentimes, what works in mice doesn’t work in humans. Nevertheless, this is encouraging news, and having access to a universal coronavirus vaccine could be a fantastic tool to protect us from this group of viruses.

The study was published in the journal of Clinical Investigation.