The spread of two new Covid-19 variants is causing concern in the US, reports The Guardian.

According to the CDC, 13 percent of all new COVID cases in the country in the first week of June were omicron variants BA.4 and BA.5. However, most new cases are an older omicron variant, although some experts believe that the two new ones may eventually take over.

The previous week, the corresponding level was 7.5 percent and at the beginning of May only one percent, according to The New York Times.

The European Union's disease control agency ECDC calls both sub-variants worrying.

Scientists have warned that the new variants are more contagious and can affect people who have previously been infected. Both subtypes have also spread rapidly around the world, with the World Health Organization (WHO) saying in May that they were responsible for a surge in cases in more than 50 countries.

In the United States, the two variants have spread particularly in the south, in states such as Texas, New Mexico, Arkansas, Oklahoma and Louisiana.

The variants were first discovered in South Africa in January and February and dominate the spread of infection there.

Source: aftonbladet.se