Highly immune evasive omicron XBB.1.5 variant is quickly becoming dominant in U.S. as it doubles weekly

Scientists say that the Covid omicron XBB. 1.5 variant is more effective at binding to cells than other subvariants.

According to the data published Friday by the Centers for Disease Control and Prevention, XBB. 1.5 now represents about 41% of new cases nationwide. Each week, the subvariant doubled as a share of cases. It doubled in the last week.

Scientists and public health officials have been keeping a close eye on the XBB subvariant family for months because of the strains that could make the Covid-19 vaccine less effective and cause more breakthrough infections.

XBB was first found in India. It became dominant there and in Singapore. XBB.1 and XBB. 1.5 are two of the subvariants.

Andrew Pekosz said that XBB. 1.5 is different from its family members because it has an additional abnormality that makes it better at binding to cells.

The virus needs to bind tightly to cells in order for it to be more efficient at infecting people.

The XBB. 1.5 variant is better at binding to cells than the XBB.1 variant, which was highly immune evasive, according to data published by a scientist.

The rise of subvariants such as XBB could compromise the efficacy of current COVID-19 vaccines and result in a surge of breakthrough infections as well as re-infections according to a study published in the journal Cell.

Many people with weak immune systems rely on the XBB subvariants for protection against Covid infections because they don't mount a strong response to the vaccine.

The scientists said the XBB resistance was alarming. The XBB subvariants were more effective at avoiding protection from the omicron boosters than the BQ subvariants.

According to Dr. David Ho, an author on the Columbia study, XBB. 1.5 probably has a growth advantage because it binding better to cells than its XBB relatives. The immune evasiveness of XBB. 1.5 is similar to that of XBB and XBB.1, two of the most resistant subvariants of the immune evasiveness of XBB.

Anthony Fauci, who is leaving his role as White House chief medical advisor, has previously said that the XBB subvariants reduce the protection the boosters give against infections.

Fauci told reporters that they could expect some protection but not optimal protection.

The case of Singapore, which had a major surge of infections from XBB but did not see hospitalizations rise at the same rate, was an example of Fauci's optimism. There is a chance that XBB. 1.5 will cause cases to rise in the U.S., but the boosters seem to be preventing severe disease.

The bivalent booster is providing continued protection against hospitalization with these variant. The need to get a booster into vulnerable populations to provide continued protection from severe disease is emphasized.

The elderly in the U.S. have been asked to make sure they are up to date on their vaccines and to get treated with Paxlovid if they have a breakthrough infections.