First discovered nearly a century ago in animals, coronaviruses have caused serious diseases in animals from mice to chickens and, more recently, humans. SARS-CoV-2 is the third zoonotic coronavirus after SARS-CoV and MERS-CoV, but appears to be the only one so far with pandemic potential.
Lisa F. P. Ng, a Senior Principal Investigator at A*STAR’s Singapore Immunology Network (SIgN), says that understanding coronavirus biology and behavior in animals will help us manage the diseases they cause in humans.
This is the basis of an editorial published in The BMJ by Ng and Julian Hiscox, Chair in Infection and Global Health at the University of Liverpool, who stem from the same ‘lineage’ of coronavirus researchers of more than 20 years. They discuss some of the main avenues where prior research on coronaviruses provide context and inform strategies for current and future outbreaks.
For example, the outbreaks of two other deadly coronaviruses, SARS-CoV and MERS-CoV, which jumped into humans from animals, reveal just how difficult it can be to control zoonotic viruses. It took over a year to contain SARS-CoV, which infected fewer people from 2002–03 than SARS-CoV-2 to date. Meanwhile, some MERS-CoV outbreaks have continued to occur since it emerged in 2012.
The authors also note that there are currently no approved vaccines or antiviral drugs against human coronaviruses. Nevertheless, Ng thinks our chances of developing a vaccine are high. “The challenge,” she noted, “will be to develop a ‘universal’ SARS vaccine.”
Meanwhile, antivirals are plagued by the possibility of resistant strains. “This happens when the antiviral drugs do not completely inhibit virus replication, but partially control the virus,” explained Ng. “This will allow a sub-species of the virus to replicate at low levels that could become totally resistant after several rounds of passages.”
To reduce the risk of resistance, the authors suggest targeting proteins that viruses use for replication in host cells, which could also reduce development time and work against multiple coronaviruses because they share similar replication mechanisms.
Given the impact of asymptomatic infections, underlying conditions and coinfections in the current and past outbreaks, the authors note that it will be important to develop accurate serological assays to help us understand the immune response of individuals.
“Understanding infection kinetics will enable the development of novel antiviral compounds to target the virus,” said Ng. “Understanding immunity and disease progression will enable the development of novel immune-based therapies against SARS-CoV-2.”
As for future outbreaks, Ng expects that the COVID-19 pandemic will equip us with the tools and knowledge needed to shut down transmission chains quickly, ranging from real-time viral genomic sequencing to the development of prognostic biomarkers.
The A*STAR-affiliated researcher contributing to this work is from the Singapore Immunology Network (SIgN).