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How SARS-CoV-2 first adapted in humans | Infectious Diseases | Scoop.it

From science.sciencemag.org - May 2, 2021 12:37 PM

Viruses need entry proteins to penetrate the cells where they will replicate. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) version is called the spike or S protein.

The S protein, also the target of the current vaccines, is quickly adapting to its new human hosts. It took its first major step in this direction early in 2020, when its amino acid 614 (of 1297) changed from an aspartic acid (D) to a glycine (G). Viruses bearing this D614G mutation transmit among humans more rapidly and now form the majority in circulation.

On page 525 of this issue, Zhang et al. (1) use careful structural analyses to reveal how D614G changed the S protein to accelerate the pandemic.

The work of Zhang et al. also reveals more about the natural history of the virus. The notable emergence of D614G suggests that the acquisition of a destabilizing furin site was a recent event. The virus could easily lose this site, as it does frequently in cell culture systems, implying that it in some way facilitates human transmission.

This is not a conclusion that most students of human coronaviruses would have anticipated, given that SARS-CoV-1, which transmits with reasonable efficiency, lacks this site, whereas the more distantly related MERS coronavirus bears this site and transmits poorly. How the SARS-CoV-2 furin site promotes new human infections remains a key open question in the field.

read the entire article at https://science.sciencemag.org/content/372/6541/466

We know a lot about Covid-19. Experts have many more questions | Infectious Diseases | Scoop.it

From www.statnews.com - April 23, 2021 1:14 PM

More than two dozen virologists, epidemiologists, and others responded to STAT's question about what they still most wanted to know.

In the 16 months since the SARS-CoV-2 virus burst into the global consciousness, we’ve learned much about this new health threat. People who contract the virus are infectious before they develop symptoms and are most infectious early in their illness. Getting the public to wear masks, even homemade ones, can reduce transmission. Vaccines can be developed, tested, and put into use within months. As they say, where there’s a will, there’s a way.

But many key questions about SARS-2 and the disease it causes, Covid-19, continue to bedevil scientists.

What accounts for the wide variety of human responses to this virus?

How much immunity is enough immunity?

How often will reinfections happen and what will they be like?

how long will immunity last?

How are viral variants going to impact the battle against Covid-19?

What is long Covid, who is at risk of developing it, and can it be prevented?

What’s the deal with Covid and kids?

How big a role do asymptomatically infected people actually play in SARS-2 transmission?

What does the future hold for SARS-2, evolutionarily and otherwise?

Can we figure out who might become a superspreader?

Can we learn more quicker from the study of the genetic sequences of SARS-2 viruses?

What is the impact of the nonpharmaceutical interventions?

What are the barriers to compliance of proven public health interventions and how can that problem best be addressed?

what are yhe differences between SARS-2 and its older cousin, SARS-1

Where did SARS-2 come from?

How SARS-CoV-2 first adapted in humans

We know a lot about Covid-19. Experts have many more questions