In December 2019, a new virus emerged that was named coronavirus 2019 (COVID-19) by the World Health Organisation (WHO) in February. The virus has been classified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is preceded by two other coronaviruses: severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). The knowledge collected from previous outbreaks along with data collection for COVID-19 will continue to provide sources of information for vaccination/drug development.
What is a coronavirus?
Coronaviruses are approximately 120 nm in diameter and are enveloped . The virus particles contain strands of RNA – RNA gives the instructions for making proteins. For the viruses, these strands provide all the information needed to make multiple copies of themselves, including the spikes on the surface of the virus, the envelope, nucleocapsid that houses the RNA and the viral membrane. In order to do this, they need to gain entry into our cells and once inside our cell, they will hijack our own cellular machinery so they can make proteins from their RNA molecule and build more viruses.
How does coronavirus spread?
In order to make copies of itself, the virus needs to find a way to enter a host’s cell. It can do this by attaching itself to molecules on the cell surface of cells in the lungs. Scientists in China have shown that in the case of COVID-19 (and SARS) the virus binds to angiotensin-converting enzyme II (ACE2) which acts as a receptor  for the spikes on the viral envelope. From here it gains entry into the cytoplasm of the cell, and will access the machinery to replicate itself. Once the virus has replicated itself, its particles are released from the cells, and this is where coughing, for example, will release these new particles from the lungs into the air in droplets, ready to be picked up by a new unsuspecting host.
Why is there not a cure?
When a new infection occurs that has not been seen before, the immune system will not be prepared to fight it. This is the same with any new disease, whether viral or bacterial. Targeting the virus means getting to know everything about it before a cure can be found and even then, it takes months or years to develop a vaccine. WHO is presently working with Chinese scientists to get over 80 clinical trials up and running so the pressure is on and I have no doubt, everything that can be done, is being done.
1. Li, X., et al., Molecular immune pathogenesis and diagnosis of COVID-19. Journal of Pharmaceutical Analysis, 2020.
2. Zhou, P., et al., A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature, 2020. 579 (7798): p. 270-273.