Prof. Walter Jaoko
Professor of medical microbiology and tropical medicine, Director KAVI Institute of Clinical Research, University of Nairobi
It is important for us to remember that all viruses evolve over time. The problem with viruses is that they keep on making mistakes as they replicate. This is not unique to the virus that causes SARS-Cov-2. Viruses make copies of themselves, unlike animals which reproduce young ones. The problem is that in the process of making copies, they sometimes make a mistake and this is what is resulting into what is called a mutation. So, if they make a mistake, such that the copy is not like the original, we say that the virus has had a mutation. Thus, when you have several of this mutation, one or two mutations, we say that now you have a new variant. You are varying from the original and that is why they are called variants.
It is vital to note that variants are not necessarily a bad thing. It is not always that a variant is a bad thing because a virus can mutate to become even less infectious. The fear is when that copy, the mutation that has been created, is highly infectious. The virus can also make a mistake and the copy that it makes, the new variant, becomes less easily spread and does not cause as much severe disease as the original virus.
Our concern should be when the mistake is made and the variant becomes more easily transmissible and causes more severe disease than the original virus.
Most viral mutations have little or no impact at all in their ability to cause infection or severe disease. But depending on where that mutation occurs in the genetic material of the virus, it may have certain effects, such as:
- Transmission: It can be much more or less easily transmitted.
- In terms of severe disease, a new variant will either cause same amount of severity, less severity or our fear is that it may cause more disease.
- The other concern is that if we have this genetic change, a virus can escape, what we call diagnostic escape, so that making diagnosis becomes difficult.
- The change, the mutation, can result in the vaccines that are currently in use not being able to work against the new mutants.
With regard to COVID-19, there are multiple variants globally but the ones we call variants of interest are basically four. These include the UK variant (B.1.1.7), South African variant (B.1.351), Brazilian variant (P.1) and the Indian variant. We call them variants of concern because they have a likelihood, although not confirmed yet, of either being more easily transmitted, causing more severe disease and dodging diagnosis.