Health authorities believe that it is possible that the omicron variant will become the dominant alternative. This affects the spread of the virus.

The omicron variant spread rapidly in South Africa, and may have led to several outbreaks in Norway.

Health authorities believe it is very likely that omicron spreads more easily than previous variants, but it is currently difficult to determine the cause.

We know the reproductive number, the R number, which says something about the average number of infected people who get infected more.

If the R number is 3, on average one infected person will infect another three. This number is affected by various factors, such as how much contact we have and how many have been vaccinated. This number is also called Rt or R.

Different virus variants also have a base R number, R0, which says something about a virus’s ability to spread before someone is vaccinated or infected – that is, in a completely unprotected population.

This makes some varieties more easily spread

In practice, an omicron variant can spread more easily than other variants for two reasons:

• increased infection
• evade immunity

There are many factors that can cause an increase in infection, such as the duration of the infection, or the amount of virus in your body.

However, if the virus survives immunity, it will easily walk away from the protection that was created after infection or a vaccine. Thus it has the potential to infect more people.

omicron protection

There is still no good data available on the omicron variant, but one can get an indication of the dispersal from what is currently known.

Assistant Director of Health Espen Rostrup Nakstad said the following about the outbreak after the Christmas table in Oslo:

— He says it’s at least as contagious as the delta variant, but he also says that vaccines protect less against the spread of infection, he says.

Recent data from South Africa also indicates that people who have already been exposed to covid-19 have a three times higher risk of omicron than delta. In other words, there are signs that the variant evades immunity from a previous infection.

Thus the delta variant could in principle have a higher R0 than the omicron, but the omicron could still become dominant because it could infect people who are protected by vaccines or exposed to a greater degree than the other variants.

Too much can affect the R number.

Does it appear to be higher R0 or higher effective?

– I cannot say for sure what is the correct answer to this, but it seems that this virus has characteristics, at least in South Africa, that lead to a marked increase in infection, says Director of Health Bjørn Guldvog.

He points out that we know for sure how different measures will affect the omicron variant, or how the variant is affected by vaccines.

– We have to get back to that, that’s what we’re looking for now. Then we also look at how this variable is affected by our climate and way of life, which may be different from South Africa, says Guldvog.

He points out that it is cooler in Norway and we live there more.

– In principle, it can lead to an increase in infection. But there may also be properties of the variable that make cold not an advantage. For now, we’re hesitant and need more knowledge, he says.