What’s the Difference Between Delta, Omicron, and BA.2 Covid Variants?

24 March 2022

Covid-19 has caused a global pandemic that has impacted every country in the world. The virus has mutated and caused different strains of the virus.

Unraveling the mystery of COVID strains: How do they mutate?

Viruses replicate thousands of times within their host. Mutations are caused by errors in this replication process. Some mutations cause the virus to evolve and make them harder to detect and treat. This, in turn, facilitates its spread within the community. The problem is, there’s always going to be a new covid variant.

How many covid variants are there? Currently, the WHO has identified 5 variants of Covid:

  1. 1. Alpha
  2. 2. Beta
  3. 3. Gamma
  4. 4. Delta
  5. 5. Omicron
  6. Variants are different mutations of the same virus. This means that although they are all related to the original strain, they all act and transmit differently.
  7. One important characteristic of each strain is its R-naught (R0) number. In simple terms, this is the average number of people that one infected person can pass the illness to – or how quickly it spreads within a community. Covid’s original strain had an estimated RO of 2, in other words, every infected person passed it on to 2 others on average.


  1. The Delta Variant

The Delta variant was first reported in India towards the end of 2020, and quickly became the dominant strain of Covid infections globally until the emergence of the Omicron covid variant in late 2021.

Although the symptoms of the Delta variant are very similar to the original version of Covid 19, the speed of the infection’s growth is significantly higher. It also differs in that it is more transmissible than the original strain, with an R0 of 7. People infected with the Delta strain are also more likely to be hospitalized.


The Omicron Variant

The Omicron variant (COVID-19, B.1.1.529) was first reported on in November 2021 in Botswana followed by South Africa. It was quickly labelled a covid Variant of Concern by the WHO and United States. By December the first Omicron case was identified in the USA and has spread rapidly around the globe since.
Omicron appears to spread faster than both the original strain and the Delta strain. Its R0 number is 10. Although initial studies show that it causes less severe illness, its tendency to spread easily could overwhelm some healthcare systems.


The Omicron BA.2 Variant

Within the Omicron variant there are sub-variants. Currently the main sub-variant of concern is the BA.2 (Also known as Nextstrain clade 21L). Some have labelled this covid variant as the stealth variant, as it is harder to detect with tests. It was first detected in the Philippines.
BA.2 spreads even faster than the original Omicron variant. It appears to be 25%-30% easier to be infected compared to the original Omicron variant. At this stage researchers do not believe it is any more deadly than its parent strain.


In Conclusion

We are likely to see further covid variants appear over time. But the basics on how to avoid any strain is the same: vaccinate, wash hands regularly and be quick to isolate if you have symptoms.