Alarm in the US due to a new variant of covid-19 XBB.1.5 0:45
(CNN) --
A new variant of covid-19, XBB.1.5, is spreading rapidly across the United States.
In December 2022, the proportion of new covid-19 infections due to this branch of omicron increased from 4% to 18%, according to a January 6 statement from the US Centers for Disease Control and Prevention. .(CDC), and is projected to rise further.
In some parts of the country, it makes up more than half of all new infections.
According to the World Health Organization, XBB.1.5 is the most transmissible form of omicron so far.
What should people know about XBB.1.5?
Do vaccines and treatments work against you?
Can tests detect it?
Will hospitals be saturated again?
Should kids wear masks at school again?
And could there be even more worrisome variants emerging in the future?
Variant of covid-19 XBB.1.5: what do we know about its symptoms?
To guide us through these questions, I spoke with CNN medical analyst Dr. Leana Wen, an emergency physician, public health expert, and professor of health policy and management at the Milken Institute School of Public Health at the George Washington University.
She is also the author of "Lifelines: A Doctor's Journey in the Fight for Public Health."
What should people know about the latest covid-19 variant, XBB.1.5?
Dr. Leana Wen:
People shouldn't be surprised that there is a new variant.
The more viruses replicate, the more they mutate.
Most mutations do not confer an evolutionary advantage and will not spread further, but some will.
There are three key questions to ask about the new variants.
First, is it more contagious?
Second, does it cause a more serious illness?
And third, is it more immune-evasive, meaning it undermines the protection of existing vaccines and treatments?
The mutations that XBB.1.5 has acquired have made it more contagious.
A more transmissible strain has the evolutionary advantage that it will spread faster than others and could therefore displace other strains.
This is a trend seen throughout the coronavirus pandemic: new, even more transmissible strains replacing their predecessors and becoming dominant.
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The good news is that, so far, this strain does not appear to cause more serious illness.
Like other descendants of omicron, it probably causes milder disease compared to the delta variants that preceded omicron.
There are some studies suggesting that XBB.1.5 is more immunoevasive compared to previously dominant omicron strains.
More research is being done to identify the degree of immune protection offered by existing vaccines;
White House Covid-19 response coordinator Dr. Ashish Jha said "the data suggests that if you've been vaccinated, if you've had that updated bivalent booster, you'll still have a fair amount of protection," during a interview Friday with CNN's Kate Bolduan.
But even if it turns out that these vaccines don't resist infection with XBB.1.5 as well, they'll probably protect well against serious disease, underscoring the need for people to get the updated booster if they're eligible.
New omicron subvariant causes most covid cases in the US 4:02
Can tests detect this new variant?
Wen:
PCR tests definitely can, and there's no reason to think that this variant won't be detected by rapid home antigen tests.
If you have symptoms or are exposed to someone with the coronavirus, you should definitely get tested.
The tests won't show you which strain you picked up, but they should detect circulating variants.
Do existing treatments against XBB.1.5 work?
Wen:
Antiviral treatments like Paxlovid should work against XBB.1.5.
Unfortunately, monoclonal antibody treatments probably won't.
In November, the US Food and Drug Administration withdrew its authorization for the last remaining monoclonal antibody due to its lack of efficacy against new variants.
And on January 6, the agency issued a statement that the Evusheld preventive antibody may be ineffective against XBB.1.5.
At the policy level, urgent investment in better treatments is critical.
There are many people vulnerable to serious outcomes due to covid-19, and we need to have a broader range of effective treatments available to them.
Could hospitals be saturated again?
Wen:
Covid-19 infections could increase in the coming weeks due to a combination of this new variant and the fact that many people will have traveled and gathered during the holidays.
However, I don't think the surge will be as bad as the initial wave of omicron in early 2022, given the large proportion of Americans who at this point have already contracted covid-19 and have some baseline immunity.
XBB.1.5 may be 'most transmissible subvariant of omicron to date', scientists warn
Increased booster rates, particularly among the elderly, will help mitigate the increase in hospitalizations.
It is a significant problem that only about a third of Americans over the age of 65 have received the updated bivalent booster, which has been shown in a recent study to reduce hospitalization by 73% in this age group.
How much should people care about XBB.1.5?
Wen:
It depends on the person.
There are many people who are not worried about contracting covid-19.
They may be young and healthy and are unlikely to get seriously ill from the coronavirus.
Perhaps they have just recovered from a previous infection and are protected from serious illness for several months.
Or maybe the downside of continuing precautions is important to them.
I don't think it's wrong for people to continue with their pre-pandemic routines, considering that XBB.1.5 is likely not the last variant of concern we see, and it doesn't seem to cause more serious illness.
On the other hand, there are many people who are worried about getting seriously ill from covid-19.
People who are elderly or have underlying health conditions should talk to their doctor about the risk of serious illness from COVID-19.
If they are at high risk even after receiving the bivalent boost, they should consider additional precautions to avoid infection while this highly transmissible variant is circulating.
That includes asking others to get a quick test before socializing and to wear a high-quality N95 mask or equivalent while in crowded indoor settings.
Some school districts are bringing back mask mandates.
Should children wear masks in schools again?
Wen:
This will depend on the family.
If everyone is generally in good health, parents or caregivers go to work without a mask, and all members socialize freely with others outside of school, then it would not add much more protection to wearing a mask in the classroom.
On the other hand, families that are still taking a lot of precautions due to, for example, a severely immunocompromised household member, might decide to wear masks in crowded indoor spaces.
My children have not worn a mask to school since the beginning of this school year, and I currently do not plan for this to change.
We would reconsider if a new variant emerged that causes much more serious illness, but that doesn't seem to be the case with XBB.1.5.
Could there be even more worrisome variants emerging in the future?
Wen:
Yes. This is why genomic surveillance is so important.
We need to identify and study new variants as they emerge.
This is part of our "new normal": there will be new variants that, from time to time, will cause waves of infections.
The key is to make sure that people are still protected from serious illness and to prevent hospitals from being overwhelmed.
And we need to make sure that everyone makes use of the tools that are available to us, including vaccinations.
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