The new COVID-19 variant, which researchers call JN.1, now accounts for about 44.1% of COVID-19 cases nationwide, the Centers for Disease Control and Prevention estimated Friday, marking another week of the fast- spread variant’s steep increase in OS
The increase is more than twice as large than the 21.3% the CDC now estimates the strain of infections for the week ending Dec. 9, after Thanksgiving.
Among regions with enough data reported from testing laboratories to produce these latest projectionsthe CDC estimates that JN.1’s prevalence is highest in the Northeast territory spans New Jersey and New York, with the strain accounting for 56.9% of cases in those states.
“JN.1’s continued growth suggests that the variant is either more transmissible or better at evading our immune system than other circulating variants. It is too early to know whether or to what extent JN.1 will cause an increase in infections or hospitalizations .” CDC said Friday.
These new estimates come as other countries have also tracked a rapid increase in JN.1’s spread in recent weeks, prompting the World Health Organization to step up the strain’s classification to “variant of interest” Tuesday — its second-highest streak.
The authorities have so far not reported other or more serious symptoms from JN.1 compared to previous strains.
Although officials so far believe the public health risk from JN.1 is no greater than that of other newer strains, its unprecedented accumulation of mutations — most inherited from JN.1s highly mutated parent BA.2.86which first caused concern during the summer – has kept the health authorities on their toes.
For months, BA.2.86 failed to gain much of a foothold around the world, despite being discovered infecting people across dozens of countries after its discovery.
JN.1’s additional mutations appear to have altered the trajectory of this strain, raising concerns that the variant may be more transmissible.
The earliest JN.1 cases in the United States were reported by laboratories from samples in September. Since then, JN.1’s share of COVID-19 cases has accelerated to become the fastest growing to date in the CDC’s biweekly “Nowcast” estimates.
Variants grouped under the BA.2.86 umbrella, which includes JN.1, have also accounted for the largest proportion of variants recovered from the CDCs airport test program on arriving international travelers in recent weeks.
CDC’s own variant classifications has not been updated since September, when BA.2.86 was first deemed a “variant under surveillance”, the lowest classification for potentially relevant variants.
In a split with the WHO, a CDC spokesman confirmed Friday afternoon that the Biden administration has so far decided not to elevate JN.1 to be a stand-alone “variant of interest.” Instead, the strain remains grouped with its BA.2.86 parent as a “monitored variant.”
“We will continue to monitor variants, including JN.1 and provide updates as information changes,” CDC spokeswoman Jasmine Reed said in an email.
Efficacy of COVID vaccines against JN.1
Data from early studies of the strain cited by WHO in a risk assessment this week also pointed to research suggesting that JN.1 “exhibits higher immune evasion” compared to its BA.2.86 parent, though not enough to prevent this season’s COVID-19 vaccines from being effective.
This year’s updated COVID-19 shot targeted the XBB.1.5 strains that led to a wave of infections earlier this year. A WHO panel earlier this month declined to call for an update to the vaccine’s recipe after considering early data so far measuring the threat posed by JN.1.
In a statement, a Novavax spokesman said data from studies in mice and non-human primates showed that its shot “induced cross-neutralization against JN.1” that was “similar” to other XBB strains.
A Pfizer spokesman said the company expects to have data in the coming weeks from tests of its vaccine against JN.1. A spokesman for Moderna did not immediately respond to a request for comment.
“We’re not sounding the alarm there, we’re keeping a close eye on it, but it’s possible that we could see a quantum leap as opposed to a gradual erosion of the protection of the vaccine. And if that happens, we’re going to have to move right quickly” Dr. Jeanne Marrazzo, head of the National Institute of Allergy and Infectious Diseases, said in an interview published Thursday by the New England Journal of Medicine.
Marrazzo said health officials were closely monitoring “endpoints like hospitalizations and deaths” as they stepped up investigation into the new strain.
WHO said early data from Belgium and Singapore suggest that JN.1 may lead to similar or reduced hospitalization risk compared to other strains.
A WHO spokesman declined to share further details about these preliminary findings with CBS News, saying the information was shared with the UN agency’s experts before being published in a journal.
So far, the CDC’s data has tracked rising COVID-19 emergency room visit and admissions not outside of what has been seen during previous winter waves.
For now, these trends are still a fraction of the steep record spike recorded during the winter of 2021-2022, which strained hospitals after the original Omicron strains swept the US over that year’s Christmas and New Year holidays.
