The list of SARS-CoV-2 variants – each with its own unique qualities that give it an edge – just keeps growing.

“The Conversation” Editor’s note: The omicron variant of SARS-CoV-2, the virus that causes COVID-19, has fueled a rapid surge in cases globally.

There are two key differences between omicron and previous variants of the SARS-CoV-2 virus that emerged in late 2019.

Early data suggests that omicron cases are milder than infections caused by the delta variant.

On the flip side, omicron is far more transmissible – meaning it spreads easier – than previous variants.

When the delta variant became dominant and displaced alpha in the summer of 2021, it managed to do so because it was between 40% and 60% more transmissible.

Now, the omicron variant is even more transmissible than delta.

In comparison with the original strain of SARS-CoV-2, omicron contains 72 mutations throughout its genome.

Initial studies suggest that omicron is more effective at reproducing in the upper airways, including the nose, throat, and mouth, than earlier variants, making it more similar to a common cold virus.

In addition, omicron is often able to evade existing immunity long enough to start an infection, cause symptoms and transmit onward to the next person.

Omicron contains a large number of mutations and is much more transmissible than earlier variants of the SARS-CoV-2 virus.

Herd immunity occurs when enough people have immunity to a virus that it no longer spreads well.

Second, vaccination or prior infection must confer enough immunity to block or slow future infections.

Will vaccination campaigns, combined with widespread omicron infection, be enough to bring herd immunity.

The first is that immunity naturally wanes over time, regardless of whether it comes from a vaccine or prior infection.

It is not yet clear how long after infection or vaccination immunity to this virus lasts, since SARS-CoV-2 has been infecting humans for only two years.

As omicron has shown, infection with one variant doesn’t guarantee protection against infection by future variants.

Most of these mutations will not be beneficial to the virus.

However, in some instances, a virus hits on a jackpot of one or more beneficial mutations that fuel its spread through a population.

The delta variant had additional mutations that improved viral spread.

Variants with beneficial mutations, such as those providing escape from antibodies or shorter incubation periods, are rapidly displacing their less fit predecessors.

The most important thing to remember about virus evolution is that natural selection favors variants that spread better than other variants.

The great news is that more pathogenic – or dangerous – variants are less likely to spread well.

Also good news is that, because infection with one variant provides partial immunity to others, omicron’s rapid spread has brought on delta’s swift decline.

At this point it is expected that all new variants that spread widely – so-called variants of concern – will continue to be highly transmissible.

In early January 2022, researchers in Cyprus reported cases of COVID-19 infections containing sequences of both omicron and delta, dubbed “deltacron.” However, other scientists are speculating that this is nothing more than a laboratory contaminant – an omicron sample contaminated with delta.

Early in the Virus emergence one nation tried the herd immunity strategy and found that mortality was much higher than prevention strategy adopted by other europen nations.

Mutation on the Virus Genome beyond the spike protien implies the structure of the Virus and its ability to fuse with the ACE 2 Cell may be enhanced (as in the case of the Omicron Variant) spreading rapidly globally but currently primarily in the west.

The Virus knows no national borders and the spread of the various variants of concern may be at various levels of progression in the local community