THE INVISIBLE KILLER

THERE IS STILL TOO MUCH UNCERTAINTY OVER WHETHER A VACCINE WOULD WORK AGAINST COVID-19

- DR DINESH ARAB

Who would have thought that the next world war would be against an invisible enemy. An enemy we cannot see and that outnumbers us by the trillions. Viruses are a strange lot. They are essentially organisms that contain nucleic acid and are surrounded by a coat of protein. They cannot be seen by an ordinary light microscope. They need a living cell to replicate. Without a host they are powerless. When viruses attack, the numbers are incredulous. Each infected cell during the flu produces 10,000 new viruses. The total number of viruses in your body can rise to 100 trillion in a few days, dwarfing the entire human population.

It is a fight for survival. We have two approaches to winning this war. One is to treat the infected, which at 2.3 million is a small proportion of the 7.8 billion worldwide population. The second is to prevent infection in the non-infected vulnerable population. That is where vaccines come into play. A vaccine uses whole or part of the virus to provide active acquired immunity. The first vaccination was done in 1796 by Edward Jenner, who showed you could develop immunity by inoculating material obtained from the hand of a milkmaid into an eight-year-old boy. He subsequently exposed the boy to small pox. The boy was unaffected and the concept of immunity was established.

The virus that causes Covid-19, SARS-CoV-2, has characteristic spikes that protrude from its surface—this is referred to as the S protein. A spike locks onto a cell receptor. The receptor then folds and the spike drills open the cell wall, and injects the viral genetic material into the cell. The genetic material then instructs your cell to produce different parts of the virus, allowing it to reproduce.