Coronavirus Briefing Newsletter


India on Friday reported 6,168 Covid cases and 21 fatalities. The cumulative caseload is 4,44,42,507 (59,210 active cases) and 5,27,932 fatalities Worldwide: Over 603 million cases and over 6.49 million fatalities. Vaccination in India: Over 2.12 billion doses. Worldwide: Over 12.14 billion doses.

TODAY’S TAKE
Shape of coronavirus affects its transmission

Since the start of the pandemic, images of the virus behind it, SARS-CoV-2, have been imprinted in our minds. But the way we picture the virus, typically as a sphere with spikes, is not strictly accurate. A global study team led by experts from Queen’s University in Canada and the Okinawa Institute of Science and Technology (OIST) in Japan has now analysed how different elliptical shapes alter the way viral particles rotate within fluids, influencing how easily the virus can be transferred. The specific type of movement that the scientists modelled is known as rotational diffusivity, which determines the rate at which the particles rotate as they move through fluid (in the coronavirus’ case, droplets of saliva). Particles which are smoother and more hydrodynamic encounter less drag resistance from the fluid and rotate faster. For coronavirus particles, this rotational speed affects how well the virus can attach to and infect cells, adds the study published in the journal Physics of Fluids. The scientists modelled both prolate and oblate ellipsoids of revolution in their study. These shapes differ from spheres (which have three axes of identical length) in just one of their axes, with prolate shapes having one longer axis, whilst oblate shapes have one shorter axis. By adding spike proteins to the surface of the ellipsoids, the team made the model the most realistic yet. Previous studies from Queen’s University and OIST demonstrated that the presence of triangular-shaped spike proteins slows the rotation of coronavirus particles, potentially enhancing their capacity to infect cells.

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A new discovery to make Covid vaccines better

Did you know that some vaccines need their own “boosters”? Adding an ingredient called an adjuvant can help protein-based vaccines elicit a more robust immune response, better training the body to fight a pathogen. Scientists have now identified a compound in marine sponges that boosted the immune response to an experimental Covid-19 shot in mice by 25 times, compared to injection with a protein-based vaccine alone. The researchers from Huazhong Agricultural University, China, noted that the tried-and-true strategy of using proteins from the pathogen can produce vaccines that are less expensive to make and easier to store. The latest study, published in the journal ACS Infectious Diseases, found that molecules derived from a-galactosylceramide (aGC), a compound from marine sponges, can act as adjuvants. These compounds work by stimulating a small population of immune cells that are important for defending the body against viral infections. The team wanted to see if they could devise a version of aGC to significantly enhance the immune response elicited by a protein-based Covid-19 vaccine. The analog called aGC-CPOEt led to the production of antibodies with the greatest neutralising capacity so far. These results suggest the compound “merits further investigation as a potential adjuvant to fight Covid and other infectious diseases”, the researchers add.