What's the purpose of segregating a virus from the blood and growing it in the lab?

Question

I heard that the scientist in Australia found a way to segregate the 2019 NovCoronovirus from the blood. Does this mean they are one step closer to the cure? Why is virus segregation crucial in finding a cure for a viral infection?

Answer 1

2019-NCoV was first cultured by a Chinese group, as published here on January 24. China has not shared samples, but did share sequencing data in the linked paper and via GISAID. The Australian group at the Doherty Institute hasn't published yet, but did put out a press release today (January 29), and appears to be the first group outside of China to have cultured 2019-NCoV.

Viral isolation, and in particular, culture, is an important, and often difficult step in characterizing a novel virus. Once characterized, viral culture serves as a gold standard for diagnosis. Generally speaking, the ability to grow virus in cell culture allows for a broad range of pre-clinical studies that can lead to clinical advances including prevention, diagnosis, and treatment. Consider how difficult it may be to study a pathogen if you are not able to manipulate it in a living culture. You can read about this in Murray Medical Microbiology, Ch 50. This article, which does not require a subscription, may also be of interest. The article describes a variety of historical and modern methods, but also includes some discussion about the use of viral culture.

Answer 2

Isolating virus particles is important for accurate genomic sequencing, which in turn enables study of mutation rates and determination of hotspots, locations in the genome where mutations occur at higher rates:

“Sorting individual viral particles makes it possible to identify and sequence the genomes of viruses one by one,” states Òscar Fornàs, head of the Flow Cytometry Unit of Pompeu Fabra University and the Centre for Genomic Regulation.

Researchers attempting to create vaccines need to know this information about the viral sequence, in order to make a functional vaccine:

Dr. Corbett and others had studied the spike proteins on SARS and MERS viruses in detail, using them to develop experimental vaccines. The vaccines never made it to market because SARS was successfully contained with public health measures before the vaccine was ready and preliminary human trials for the MERS vaccine showed success last year.

But the scientists had a method for developing vaccines that could help them fast-track production for the new coronavirus. They used the template for the SARS vaccine and swapped in just enough genetic code that would make it work for the new virus. “I call it plug and play,” Dr. Corbett said.

Characterizing how quickly a virus mutates, and where, can decide the effectiveness of a vaccine.

In the United States, for example, this year's batch of influenza vaccine did not match up well with the strain of flu virus that ended up becoming dominant:

An unusual viral strain is dominating flu activity across the United States and may be one reason for the severe infections in children so far, according to a new report from the Centers for Disease Control and Prevention, and this season’s influenza vaccine is not a close match for the virus.

There are limited resources to allocate to vaccine development. Faster and more accurate sequencing can help with a more targeted and effective response.