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U.S. scientists have shown for the first time that coronavirus vaccines and infections can confer immunity to other, similar coronaviruses.
Mice vaccinated against 2003 SARS virus were protected from COVID-19 virus
Humans vaccinated with SARS-CoV-2 vaccines may be protected against SARS-CoV-1 and colds.
Results provide rationale for developing universal vaccines for each coronavirus family
“Until our study, it was not clear whether, when exposed to one coronavirus, you could have cross-protection against other coronaviruses. We have now shown that this is the case.” Pablo Penaloza-MacMaster, assistant professor of microbiology-immunology at Northwestern University Feinberg School of Medicine, is pleased. His study, published recently in the Journal of Clinical Investigation, fuels hopes for universal coronavirus vaccines that could prove useful in the face of future epidemics.
The coronavirus families
The three main families of coronaviruses that cause disease in humans are:
- the Sarbecovirus, which includes the SARS-CoV-1 strain responsible for the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak, and SARS-CoV-2, responsible for COVID-19;
- Embecovirus, which includes OC43, often responsible for colds;
and the - merbecovirus responsible for Middle East Respiratory Syndrome (MERS), first reported in 2012.
Plasma from people who had been vaccinated against SARS-CoV-2 produced antibodies that were cross-reactive (protective) against SARS-CoV-1 and the common cold coronavirus (OC43), the current study now shows. The study also found that mice vaccinated against SARS-CoV-1 with a vaccine developed in 2004 developed immune responses that protected them against SARS-CoV-2. Finally, the study found that previous coronavirus infections may protect against subsequent infections with other coronaviruses.
Protection in other corona viruses
Mice immunized with COVID-19 vaccines and later exposed to cold coronavirus (HCoV-OC43, which is distinct from a SARS strain) were partially protected against the common cold, but the protection was much less robust, the study found.
Genetically similar
Scientists explain this by noting that both SARS-CoV-1 and SARS-CoV-2 are genetically similar – like cousins – while the cold coronavirus differs from SARS-CoV-2. Says Penaloza-MacMaster, “As long as the coronavirus is more than 70 percent related, the mice were protected. If they were exposed to a very different family of coronaviruses, the vaccines might offer less protection.”
Are universal corona vaccines possible?
Given how different each coronavirus family is, the answer is probably no, the study authors write. But there may be a way to develop a vaccine for each coronavirus family (sarbecovirus, embecovirus and merbecovirus).
Currently, Penaloza-MacMaster’s team is studying how long this cross-protection lasts.
- source: kurier.at/picture: pixabay.com
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