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The Omicron variant of coronavirus has become the new dominant strain and has changed the course of the pandemic, leading to a dramatic rise in cases around the world. Besides, new Omicron sub-variants BA.2, BA.4, and now BA.5 have also wreaked havoc around the world. There's a growing concern that this new sub-variant may lead to people becoming reinfected, leading to another global surge.
Why are there so many types of Omicron?
A mutation is a common concept in viruses. However, according to a report by The Conversation, the vast majority of mutations have little to no effect on the ability of the virus to transmit from one person to another or to cause severe disease.
When a virus accumulates a substantial number of mutations, it’s considered a different lineage (somewhat like a different branch on a family tree). But a viral lineage is not labelled a variant until it has accumulated several unique mutations known to enhance the ability of the virus to transmit and/or cause more severe disease.
This was the case for the BA lineage (sometimes known as B.1.1.529) the World Health Organization labelled Omicron. Omicron has spread rapidly, representing almost all current cases with genomes sequenced globally.
Because Omicron has spread swiftly and has had many opportunities to mutate, it has also acquired specific mutations of its own. These have given rise to several sub-lineages, or sub-variants.
Is Omicron sub-variant a big threat?
As per the global evidence, the Omicron sub-variants (especially BA.4 and BA.5) are particularly effective at reinfecting people with previous infections from BA.1 or other lineages. There is also concern these sub-variants may infect people who have been vaccinated.
However, recent research suggests a third dose of the COVID vaccine is the most effective way to slow the spread of Omicron (including sub-variants) and prevent Covid hospitalisation.
"Recently, BA.2.12.1, has also drawn attention because it has been spreading rapidly in the US and was recently detected in wastewater in Australia. Alarmingly, even if someone has been infected with the Omicron sub-variant BA.1, re-infection is still possible with sub-lineages of BA.2, BA.4 and BA.5 due to their capacity to evade immune responses," The Conversation noted.
Future of Covid pandemic
As long as the virus is circulating, Covid's new virus lineages and variants will continue to occur. Scientists will continue to track new mutations and recombination events (particularly with sub-variants). They will also use genomic technologies to predict how these might occur and any effect they may have on the behaviour of the virus.
