By Chetna Gill
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| Cover Image Attribute: A file photo of the main entrance of the Wuhan Institute of Virology. It is a research institute under the Chinese Academy of Sciences, located in the Jiangxia District, south of Wuhan city, Hubei province, China. |
Five years after the COVID-19 pandemic gripped the world, a new bat-derived coronavirus has emerged from the laboratories of the Wuhan Institute of Virology (中国科学院武汉病毒研究所), reigniting debates about zoonotic diseases, laboratory safety, and the origins of pandemics. Named HKU5-CoV-2, this virus bears striking similarities to SARS-CoV-2—the pathogen responsible for millions of deaths worldwide—prompting both scientific intrigue and public unease. Discovered by a team led by renowned virologist Shi Zhengli, the finding has thrust the Wuhan lab back into the spotlight, a place it has occupied uneasily since speculation about COVID-19’s origins first surfaced in 2020.
Published on February 22, 2025, in the prestigious journal Cell, the identification of HKU5-CoV-2 comes at a time when the world is still grappling with the legacies of COVID-19: economic disruptions, lingering health challenges, and a fractured global trust in scientific institutions. While experts emphasize that the new virus does not currently pose an immediate threat, its discovery raises critical questions about humanity’s preparedness for future pandemics and the role of high-risk virological research in preventing—or potentially precipitating—them.
What is HKU5-CoV-2?
HKU5-CoV-2 is a novel strain of coronavirus classified within the merbecovirus subgenus, a family that includes the deadly Middle East Respiratory Syndrome (MERS) virus. The virus is an offshoot of the HKU5 lineage, originally identified in Japanese pipistrelle bats in Hong Kong over a decade ago. What sets HKU5-CoV-2 apart—and what has alarmed some observers—is its ability to bind to the human ACE2 receptor, the same cellular gateway exploited by SARS-CoV-2 to infect human cells during the COVID-19 pandemic.
The ACE2 receptor, found on the surface of cells in the lungs, heart, kidneys, and intestines, acts as a molecular docking station for certain coronaviruses. HKU5-CoV-2’s affinity for this receptor suggests it has the potential to jump from bats to humans, either directly or through an intermediate host, much like its infamous predecessor. Laboratory experiments conducted by the Wuhan team confirmed that the virus can infect human cells expressing high levels of ACE2, as well as models of human lung and intestinal tissues. However, its binding efficiency is notably weaker than that of SARS-CoV-2, indicating a lower immediate risk of widespread human transmission.
Another notable feature of HKU5-CoV-2 is the presence of a furin cleavage site in its spike protein. This molecular quirk, also found in SARS-CoV-2, enhances a virus’s ability to penetrate cells, making it more transmissible or virulent. During the Covid-19 pandemic, the furin cleavage site became a focal point of scientific debate, with some researchers suggesting it could indicate artificial manipulation—a theory that remains unproven and contentious. In HKU5-CoV-2, this feature appears naturally derived, but its presence nonetheless amplifies the virus’s potential significance.
Despite these concerning traits, the Wuhan researchers and independent experts agree that HKU5-CoV-2 is not currently optimized for human infection. Its reduced infectivity, combined with global immunity built from COVID-19 vaccinations and natural infections, likely limits its capacity to spark a new pandemic. Still, the virus’s discovery serves as a stark reminder of the unpredictable nature of coronaviruses and the ever-present risk of zoonotic spillover.
The Discovery Process
The identification of HKU5-CoV-2 stems from ongoing research into bat coronaviruses, a field in which Shi Zhengli—often dubbed "Batwoman" for her decades-long study of these mammals—has been a global leader. Working with collaborators from Guangzhou Laboratory, Guangzhou Academy of Sciences, and Wuhan University, Shi’s team isolated the virus from bat samples collected in southern China. Through advanced genomic sequencing and laboratory testing, they mapped its structure, assessed its infectivity, and explored potential countermeasures.
In their Cell paper, the researchers detailed how HKU5-CoV-2 infects human cells and tissue models, albeit with less efficiency than SARS-CoV-2. They also tested existing treatments, finding that monoclonal antibodies and antiviral drugs developed for Covid-19 could neutralize the new virus in lab settings. This overlap suggests that the global medical toolkit, honed during the last pandemic, could be repurposed if HKU5-CoV-2 were to pose a future threat.
Shi and her co-authors framed their work as a proactive effort to understand and mitigate zoonotic risks. "Bat merbecoviruses represent a high-priority group for surveillance due to their demonstrated ability to cross species barriers," they wrote. "By studying their mechanisms, we can better prepare for potential spillovers." The team emphasized that their research adheres to strict biosafety protocols, a point intended to address lingering concerns about the Wuhan lab’s practices.
A Controversial Backdrop
The Wuhan Institute of Virology is no stranger to scrutiny. Since early 2020, it has been at the epicenter of theories suggesting that SARS-CoV-2 may have escaped from its facilities, either through accidental release or as a result of gain-of-function research—experiments that enhance a virus’s transmissibility or pathogenicity. These claims, amplified by politicians, scientists, and online communities, have never been conclusively proven, and both the Chinese government and Shi Zhengli have vehemently denied them. Beijing insists that COVID-19 emerged naturally, likely via a wet market in Wuhan, and has accused critics of politicizing science.
The discovery of HKU5-CoV-2 has inevitably reignited this debate. On X, reactions range from cautious curiosity to outright suspicion. "Another COVID-like virus from Wuhan? What are the odds?" one user posted, echoing a sentiment shared by thousands. Others pointed to the lab’s history, with one writing, "They’re either the unluckiest researchers alive or something’s not adding up." Scientists, however, urge restraint. "Finding coronaviruses in bats isn’t surprising—they’re a natural reservoir," said Dr. Peter Daszak, a virologist with EcoHealth Alliance, in a statement to Nature. "The real question is what we do with this knowledge."
Chinese authorities have moved quickly to counter speculation. At a press briefing on February 22, Foreign Ministry spokesperson Guo Jiakun reiterated that the Wuhan lab "has never designed, made, or leaked" any virus, including SARS-CoV-2. He described the HKU5-CoV-2 discovery as a triumph of Chinese science, not a cause for alarm. "This is about protecting humanity, not threatening it," Guo said.
Scientific and Global Implications
The emergence of HKU5-CoV-2 underscores the persistent threat posed by zoonotic pathogens, particularly those harbored by bats. These flying mammals are unique in their ability to host a wide array of viruses without succumbing to illness, making them ideal reservoirs for diseases that can leap to humans. MERS, SARS, and Covid-19 all trace their origins to bat coronaviruses, and HKU5-CoV-2 joins a growing list of potential candidates.
The World Health Organization (WHO) has long classified merbecoviruses as a priority for pandemic preparedness, a stance reinforced by this latest finding. In a statement on February 23, WHO officials praised the Wuhan team’s transparency while calling for expanded global surveillance of bat populations and their viruses. "Understanding these pathogens is the first step to preventing the next outbreak," the statement read.
For now, HKU5-CoV-2 remains a theoretical risk rather than an active one. Its weaker adaptation to human cells and the residual immunity from Covid-19 likely diminish its immediate danger. Yet experts warn that viruses can evolve unpredictably, especially if they pass through intermediate hosts like civets or pangolins, as SARS and Covid-19 may have done. Ongoing research will focus on mapping HKU5-CoV-2’s evolutionary trajectory and identifying any conditions under which it could become more transmissible.
Public Reaction and the Road Ahead
Beyond the lab, HKU5-CoV-2 has captured public attention in a way few scientific discoveries do. The echoes of COVID-19—lockdowns, masks, and loss—are still fresh, and the news of another potential threat has stirred a mix of fatigue, fear, and skepticism. Online forums and social media platforms buzz with discussion, some of it informed, much of it speculative. "We’ve been here before," one X user wrote. "Why should we trust this won’t spiral out of control?"
Scientists are working to bridge this trust gap. Shi Zhengli, in a rare public comment, told Science magazine, "Our goal is to protect, not to harm. The more we know, the safer we all are." Her team plans to continue studying HKU5-CoV-2, sharing data with international partners to ensure a coordinated response if the virus’s risk profile changes.
As on date, HKU5-CoV-2 stands as both a scientific milestone and a cautionary tale. It highlights the delicate balance between exploring nature’s mysteries and guarding against its dangers—a balance that, five years after COVID-19, humanity is still learning to strike. Whether this virus fades into obscurity or becomes a footnote in the next chapter of global health remains uncertain. For now, it is a reminder that in the realm of infectious diseases, vigilance is the price of survival.
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