If you've had omicron before, are you safe from infection by the new variants?

A woman is wearing a face shield to protect her from a surge of COVID-19 at a taxi stand in South Africa.

Denis Farrell/AP

One thing seems certain to bioinformatician Shishi Luo: another surge will occur.

New versions of omicron are emerging in the United States and other parts of the world, like South Africa.

The new versions of omicron have a set of key changes which allow them to spread faster than the previous versions.

People are wondering if they can get omicron again.

Two studies published online this week will answer that question. The results show how quickly omicron can change.

How the variants are faring in the U.S. and South Africa

Let's look at what these variant are doing in the U.S. and South Africa before we get to the studies.

There was a steep rise in cases in central New York state due to the new version of omicron called BA.2.12.1. The omicron BA.2, which has been dominant in the U.S. variant, has been found across the country.

It will definitely come to dominate here, given how this new variant is rising in the U.S. How big will it be? I don't know what the answer is. It depends on people's behavior.

The new omicron variant BA.4 and BA.5 are causing a fifth wave of cases in South Africa. In the past two weeks, the number of cases there has nearly doubled. The positivity rate went from 8% to 18%.

Omicron is a 'master player'

The new variant shows how wily omicron is.

Omicron is a master player when it comes to evading antibody activity. Pei-Yong Shi, a researcher at the University of Texas Medical Branch at Galveston, says that it is more efficient than previous versions.

The two new studies explain why the new variant has started to spread so quickly. One key factor is their ability to re-infect people who have already had an omicron infection. The risk of reinfection may be higher for people who are not vaccine-free.

Researchers took blood from people with the original omicron variant, BA.1, and looked to see if the antibodies in the blood could counteract newer versions of omicron, including the one that emerged in New York state.

All people with omicron BA.1 had neutralizing antibodies. The new variant had a decrease in potency. The amount of decline depended on the people being vaccine free.

The activity against BA.4 and BA.5 dropped by nearly 8 times for people who weren't vaccinations.

Alex Sigal, who led one of the studies, said that the neutralization capacity after BA.4/5 was very low. The potency went down by about 4 times against BA.2.12.1.

In one of the studies, biophysicist Sunny Xie and his colleagues from Peking University write about how Omicron can evolve to evade immunity.

What vaccines can and can't do

Sigal, who is at the Africa Health Research Institute, said that the situation was better in the vaccine breakthrough cases. The neutralization ability dropped only 3 fold for people who received the Pfizer vaccine or the Johnson & Johnson vaccine. The people had more neutralization capacity against BA. In the end, they had about 5 times the neutralization potency against the new variant, compared to people who weren't vaccinations before.

The data shows that the vaccine still has great benefits, according to Pei-Yong Shi.

Sigal believes that the decline in antibody potency is enough to cause trouble and lead to an infection wave like in South Africa, where only a third of the population is immunized.

De Oliveria says that previous infections with Omicron BA.1 will not be enough to prevent a second one.

Some scientists believe that one needs a new variant to cause a new wave. Omicron is causing waves.

BA.4 and BA.5 are very rare in the US. The Centers for Disease Control and Prevention estimates that about a third of all cases in the U.S. are related to BA. 2.12.2.