The New York Times, January 12, 2023


Three years into the pandemic, the coronavirus continues to impress virologists with its swift evolution.

Here are answers to some common questions about the fast-growing variant XBB.1.5.

Do Vaccines Provide Protection Against XBB.1.5?

XBB.1.5 can evade some of the antibodies produced either by vaccines or by infections with older versions of the coronavirus. But bivalent boosters appear to provide extra protection against infection, and will probably do a good job of reducing the risk of hospitalization, especially for older people who are at most risk of serious disease and death.

Is XBB.1.5 More Dangerous Than Earlier Forms Of The Virus?

There’s no evidence yet that it causes more severe disease. But it will take time for scientists to gather enough data to make a firmer assessment.

Is An XBB.1.5 Infection Treatable?

Yes. XBB.1.5 remains vulnerable to Paxlovid, an antiviral pill. However, monoclonal antibodies that were effective against earlier forms of the virus are largely useless against XBB.1.5 because of its new mutations.

When Did XBB.1.5 Appear?

The earliest known samples of XBB.1.5 date to late October, but it’s likely that it was circulating before then.

Where Did XBB.1.5 Come From?

The ancestors of XBB.1.5 may have been in India. But the earliest samples of XBB.1.5 came from the northeastern United States. So it’s likely that XBB.1.5 underwent its final evolution there.

Is XBB.1.5 Common?

Worldwide, XBB.15 is still fairly rare. As of early January, it accounted for less than 1 percent of coronaviruses being sequenced. For now, it is most common in certain hot spots, like the northeastern United States, where it makes up about three-quarters of new cases.

Is XBB.1.5 A Cause For Serious Concern?

Yes. Even though it is still rare, it is multiplying much faster than other subvariants of Omicron. However, many experts doubt it will produce a record-breaking wave of infections the way Omicron did in early 2021.

Copyright 2023 The New York Times Company. Reprinted with permission.