Syringes containing the Moderna COVID-19 vaccine in Needham, Mass., in a 2022 file photograph. (Joseph Prezioso/AFP via Getty Images)
The Epoch Times
By Zachary Stieber
The new COVID-19 vaccines don’t work as well against XBB.1.5, the virus variant that’s now dominant in the United States, according to multiple studies.
In one of the papers, researchers found the vaccines boosted neutralizing antibodies, believed to be a measure of protection, but that the antibody levels declined to previous levels within three months.
Compared to the antibody responses to BA.5, the responses to XBB.1.5 were reduced 20-fold.
“Following bivalent mRNA boosting, responses to XBB.1.5 increase but remain low and wane within 3 months back to pre-boost levels. These data suggest that once a year boosters with the current mRNA vaccines may not provide adequate protection for an entire year for those at high risk of complications of COVID-19,” Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at the Beth Israel Deaconess Medical Center and a co-author of the preprint study (pdf), told The Epoch Times via email.
The Moderna and Pfizer vaccines both utilize messenger RNA, or mRNA, technology. The updated versions of the vaccines are bivalent, targeting the Wuhan variant and a sublineage of the BA.4 and BA.5 strain. The new versions were cleared as boosters in the fall of 2022 despite no clinical data being available. They are poised to replace the original vaccines.
Other studies have also found that the bivalents induce a better response than the old, monovalent boosters, but that the response is reduced against XBB.1.5 or its parent, XBB, which comes from BA.2 lineages.
Researchers with Pfizer and Pfizer partners, for instance, reported recently that the antibody levels were the lowest against XBB.1.5, and were particularly low among people without evidence of prior infection. Similarly, researchers with the U.S. National Institutes of Health and other institutions concluded (pdf) that “the lowest titers were observed against XBB.1” and researchers with the U.S. Centers for Disease Control and Prevention (CDC) detected (pdf) “low activity” against XBB.1. And Japanese scientists also observed a reduction in neutralizing power.
“We are seeing increasing escape with more contemporary variants like XBB.1 from the ability of the currently adapted and updated bivalent booster vaccines to produce an efficient antibody response that neutralizes the virus,” Dr. Angela Branche, with the University of Rochester, who co-wrote one of the papers, told The Epoch Times via email. While the vaccines “will continue to provide protection against severe disease,” they “will need to be further optimized to keep up with the pace of virus evolution,” she added.
A group of Chinese researchers, who reported evidence that XBB.1.5 can more easily evade protection, said that the circulation of the strain “needs to be closely monitored, and the development of effective neutralizing antibodies and vaccines against XBB.1.5 is urgently needed.”
“Based on its genetic characteristics and growth rate estimates, XBB.1.5 is likely to contribute to increases in case incidence globally. There is moderate-strength evidence for increased risk of transmission and immune escape. From reports by several countries, no early signals of increases in severity have been observed,” the World Health Organization stated in a risk assessment (pdf), though it acknowledged that the low number of cases caused by the strain does not enable a confident assessment of severity.
New York officials claimed in January that XBB.1.5 “may be more likely to infect people who have been vaccinated or already had COVID-19,” later adding that they meant compared to prior variants. When asked for evidence to back up the claim, a spokesperson declined to provide any.
Authorization Revoked as XBB Becomes Dominant
Regulators have not yet altered authorizations or approvals for vaccines, but the U.S. Food and Drug Administration (FDA) yanked authorization for Evusheld, a monoclonal antibody treatment, because it said the drug wouldn’t work against XBB.1.5 and other emerging subvariants.
XBB.1.5, an Omicron subvariant like BA.5, was estimated to be behind 66.4 percent of the COVID-19 cases in the United States in the week ending Feb. 4, according to genomic sequencing and other data.
BA.5 was the dominant strain until late 2022, when it was displaced by BQ.1.1 and BQ.1. Those Omicron subvariants make up about a quarter of the cases.
The bivalent vaccines were cleared in part because the vaccines had been performing increasingly worse against Omicron and its subvariants. Regulators chose not to wait for clinical data despite widespread warnings that authorizing the shots without the data would further undermine confidence in the COVID-19 vaccines.
The FDA met with its advisory panel in January but none of the vaccine makers that made presentations during the meeting, including Pfizer and Moderna, presented clinical efficacy data. Officials from the companies alleged that testing data indicated the vaccines work against XBB.
CDC researchers, drawing from testing data, estimated similar vaccine effectiveness (VE) against XBB and BA.5.
For people aged 18 to 49, for instance, the relative effectiveness against symptomatic infection was estimated at 52 percent two to three months after a bivalent booster against the latter and 48 percent against the former.
Relative effectiveness means effectiveness beyond the initial shots, which provide little protection against symptomatic infection.
“‘Generally, VE against symptomatic infection is similar for the two sub lineages and across age groups,” Dr. Ruth Link-Gelles, a CDC researcher and co-author of the report, told the FDA’s advisory panel.
“We’re continuing to monitor this as XBB.1.5 continues to increase nationally,” she added.
Researchers drew from the Increasing Community Access to Testing program, which provides free COVID-19 testing at CBS, Walmart, and other places.