PHILADELPHIA (CBS) -- There are new warnings about the newest COVID-19 subvariant -- it may be the most transmissible one to date. Cases are on the rise again.
We have a double whammy of a post-holiday surge of COVID-19 cases and much of the increase is being driven by the new subvariant that's easily spreading.
The World Health Organization is calling XBB.1.5 the most transmissible subvariant detected yet.
"It does have a growth advantage above all of the other subvariants so far," Maria van Kerkhove, the WHO COVID-19 technical lead, said. "We don't have any data on severity yet or on the clinical picture."
New CDC data shows COVID-19 deaths are increasing and hospitalizations are now at 47,000 nationwide, higher than this summer's peak.
"The numbers are double from where we were, for instance, a few weeks ago," Dr. Martin Topiel, infection control chief at Virtua Health, said. "This is probably the most we've seen in close to a year."
He is seeing a post-holiday surge of COVID-19 cases driven by the new subvariant.
"The so-called XBB variant that seems to have a higher transmission rate than even previous omicron viruses," Topiel said.
The CDC COVID-19 Community Level Map shows cases are high all over New Jersey and in Southern Delaware. Levels are medium in southeastern Pennsylvania,
The CDC recommends people wear masks indoors in locations where levels are high.
"The transmission rates in New Jersey are higher than they've been for quite some time," Topiel said.
"I try to keep going to do what I need to to try and stay safe," a masked person said.
In addition to wearing masks, doctors say the COVID-19 booster is the best protection.
"The new bivalent vaccine - this is the new one that we updated in September - it does seem to provide a great degree of protection against infection and terrific protection against serious illness," Dr. Ashish Jha, White House COVID-19 response coordinator, said.
U.S. officials are also concerned about the growing COVID-19 crisis in China and a lack of information-sharing.
They say it makes it harder for the scientific community to spot new variants as they emerge.
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