Jan. 25 (UPI) -- New bivalent booster shots cut the risk of contracting COVID-19, including from the latest variant of the virus, according to new data published Wednesday by the U.S. Centers for Disease Control and Prevention.
"Results showed that a bivalent mRNA booster dose provided additional protection against symptomatic XBB/XBB.1.5 infection for at least the first 3 months after vaccination in persons who had previously received 2-4 monovalent vaccine doses," reads the CDC report published Wednesday.
The CDC looked at test results from about 30,000 people in December and the first part of January.
It found people who had taken the bivalent mRNA booster shots manufactured by Pfizer or Moderna were at less risk of contracting mild illness from a group of sub-variants from the XBB family, the latest incarnation of the SARS-CoV-2 virus.
The XBB.1.5 sub-variant is expected to become the first recombinant variant to become dominant in the United States, officials warned earlier this month. The variant was created by two existing Omicron sub-variants merging.
Wednesday's news from the CDC looks at the effectiveness of booster shots against that variation.
Of the cases looked at by CDC researchers, most of those testing negative had already taken one of the bivalent boosters.
"It's too early, I think, to know how waning will happen with the bivalent vaccine. We know from the older vaccines that we do see protection decrease over time, especially against symptomatic infection. Just like with overall protection, what we've seen in the past is, your protection lasts longer for more severe illness," epidemiologist Ruth Link-Gelles, the study's lead author, said during a news conference Wednesday.
"We will continue to monitor it over time in the coming months."
Researchers also found booster shots' effectiveness differed with age.
Those between 18 and 49 were protected most from mild illness by taking a booster, giving them 48% protection three months after the shot. That number dropped to 38% for those between 50 and 64, and 42% for those over the age of 65.
The CDC publication represents the closest thing to real-time data compiled so far on COVID-19 and the effectiveness of the bivalent booster shots.
