The Covid-19 pandemic has reignited interest in a so-called "pancoronavirus" vaccine—one that could protect people against all coronaviruses, including SARS-CoV-2, its variants, and even some seasonal colds—and their early research has shown promising results, Carl Zimmer writes for the New York Times.
For many years, vaccine makers didn't focus much effort on coronaviruses, Zimmer writes, because the family of viruses appeared to cause only mild colds.
That changed in 2002, when a new coronavirus—called SARS-CoV—emerged and began causing a fatal pneumonia known as severe acute respiratory syndrome (SARS). According to Zimmer, scientists started researching a vaccine for SARS-CoV, but interest in a vaccine waned after the virus was quickly contained via quarantine and other efforts.
In 2012, a second coronavirus, called MERS-CoV, emerged—causing yet another fatal respiratory disease, called MERS, and further confirming the threat of coronaviruses, Zimmer writes. At the time, researchers began mulling the idea of developing a pancoronavirus vaccine, but the idea floundered as funders addressed other, seemingly more pressing needs. MERS, like SARS, caused comparatively few deaths, and other viruses—including Eloba and Zika—required more immediate attention, Zimmer explains.
Then, in 2019, a third coronavirus, called SARS-CoV-2, emerged and triggered the Covid-19 pandemic, Zimmer reports. Although SARS-CoV-2 has a lower fatality rate than other coronaviruses, it spreads more easily from person to person, leading to more than 106 million infections worldwide to date, Zimmer reports.
According to Zimmer, previous research into coronavirus vaccines facilitated the record-breaking speed with which the currently available Covid-19 vaccines were developed. But vaccine development still took more than a year—and future coronaviruses remain a distinct threat.
"This has already happened three times," said Daniel Hoft, a virologist at Saint Louis University, told Zimmer. "It's very likely going to happen again."
Amid this renewed interested, researchers at VBI Vaccines, a Cambridge-based biotech company, last summer developed a vaccine that included spike proteins from the three coronaviruses that cause SARS, MERS and Covid-19.
When they injected their vaccine into mice, they found the mice developed antibodies against all three coronaviruses—and they also found some of the antibodies could attach themselves to a fourth human coronavirus that causes seasonal colds, even though they hadn't included that virus's spike proteins in the vaccine.
The researchers announced their findings in a release last year, but they have not yet published their results in a scientific journal. Speculating on the findings, however, David Anderson, VBI's chief scientific officer, hypothesized the vaccine may spur the body to make a compromise antibody that works against multiple versions of a coronavirus, rather than individual antibodies to address each version independently. "You're educating [the immune system]," he suggested.
Pamela Bjorkman, a structural biologist at the California Institute of Technology, and her colleagues achieved similar results, which were published last month in the journal Science, when they "attached only the tips of spike proteins from eight different coronaviruses to … a nanoparticle," Zimmer writes. According to the study, mice injected with the nanoparticles produced antibodies that were effective against all eight of the coronaviruses—as well as for four other coronaviruses the researchers hadn't included in the vaccine.
Kayvon Modjarrad, the director of Emerging Infectious Diseases Branch at Walter Reed Army Institute of Research, is leading research on a separate vaccine based on a nanoparticle studded with fragments from SARS-CoV-2's spike proteins, which Modjarrad and his colleagues are aiming to reconfigure as a pancoronavirus vaccine, Zimmer reports. Modjarrad and his colleagues expect clinical trials for the vaccine will start next month.
Meanwhile, Hoft is collaborating with Gritstone Oncology, a California-based biotech company, on a potential pancoronavirus vaccine that triggers the production of surface proteins, rather than spike proteins, common to coronaviruses. Hoft and his colleagues are now preparing to start a clinical trial to determine whether the vaccine is effective against SARS-CoV-2.
"We are interested to develop maybe a third-generation vaccine, which would be on the shelf and ready for the future outbreak," Hoft said.
So how soon could scientists develop a pancoronavirus vaccine?
Eric Topol—director of the Scripps Research Translational Institute, who earlier this week urged scientists in the journal Nature to develop "variant-proof" vaccines that generate broadly neutralizing antibodies—thinks it may happen relatively quickly, since all coronaviruses are similar. "This is an easy family of viruses to take down," he told Zimmer.
But even if it takes scientists a few years to create a pancoronavirus vaccine, such an inoculation could help protect the world from another coronavirus pandemic, Zimmer writes.
"I think we can have vaccines to prevent pandemics like this," Matthew Memoli, a virologist at the National Institute of Allergy and Infectious Diseases, said. "None of us wants to go through this again. And we don't want our children to go through this again, or our grandchildren, or our descendants 100 years from now" (Zimmer, New York Times, 2/10).
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