[Lewis Thomson (OP)]

Charles has been curious about this question.

"What has happened to the Alpha, Beta and Gamma strains? All the news is of the Delta and Omicron variants."

Leave your thoughts in the comments below...

[evan_au]

The later variants (Delta, Omicron) are more infectious than earlier variants (higher R₀).
- Public health measures aimed at controlling the later variants reduce the R_eff of the earlier variants (Wuhan, Alpha) below 1, and they die out.
- The problem with the "Let it Rip" philosophy with Omicron is that it won't reduce the R_eff of Delta below 1, so it will stay around in the population at a low level.
        - Once most people have caught Omicron and are immune to Omicron, Omicron will die down.
       - But Delta is still present in the population, and Omicron probably doesn't provide much protection against catching Delta, so Delta may continue to spread among the unvaccinated.

See: https://ourworldindata.org/grapher/covid-cases-omicron?tab=chart&country=GBR~FRA~BEL~DEU~ITA~ESP~USA~ZAF~BWA~AUS