SUITA, JAPAN (WWTI) — Scientists have recently developed a vaccine that could end pandemics caused by diseases that emerge in animals, a new study reveals. In experiments, the vaccine halted five different types of coronaviruses in their tracks — including COVID-19.
COVID has already claimed around five million lives worldwide. Health officials warn that viruses jumping from animals to humans are becoming increasingly common. Recent health crises have included bird flu, swine flu, and Ebola that originated in monkeys. Meanwhile, MERS — another coronavirus strain — has been linked to camels. Outbreaks among people tend to stem from the exploitation of wildlife, including intense battery farming and selling meat for food.
“Given that prior coronavirus epidemics such as SARS-CoV-1 and MERS-CoV have occurred due to zoonotic coronaviruses crossing the species barrier, the potential for the emergence of similar viruses in the future poses a significant threat to global public health, even in the face of effective vaccines for current viruses,” says study lead author Professor Tomohiro Kurosaki of Osaka University in a media release.
One of the theories surrounding COVID-19 is that it began in bats and leaped to another animal before reaching humans. It enters human cells by using its spike protein to bind to the ACE2 cell surface receptor. The study finds this virus consists of two parts: a “core” that is very similar in all coronaviruses and a more specialized “head.”
The Japanese team genetically engineered the spike protein of SARS-CoV-2 — the virus that causes COVID. Covering its head with additional sugar molecules made it impossible to hook onto the ACE2 protein in human cells that leads to infection.
In vaccinated mice, the production of antibodies against the unshielded core, mid-section of the viral protein, was dramatically boosted. They blocked SARS-CoV-2 and SARS-CoV-1, which triggered the SARS outbreak in 2002. Three similar coronaviruses from bats and pangolins also hit a “stone wall,” according to the researchers.
Antibodies recognizing this viral head can block the entry of SARS-CoV-2 into cells, but offer little protection against other coronaviruses. Antibodies that identify the core, on the other hand, can prevent the entry of various coronaviruses into human cells.
The researchers say this new strategy fuels antibodies that neutralize multiple coronaviruses however, individuals exposed to the viral spike protein tend to only produce antibodies against the head.
“This suggests that, although the generation of broadly neutralizing antibodies is possible, SARS-CoV-2 infection and current vaccines are unlikely to provide protection against the emergence of novel SARS-related viruses,” Prof. Kurosaki explains.
The study opens the door to a next-generation vaccine that will reduce the risk of pandemics. The research team is hopeful with more work it can be successfully translated to humans.
The findings appear in the Journal of Experimental Medicine.