The New COVID-19 Strain Information from the CDC

The latest COVID-19 strain information from the CDC indicates that KP.3.1.1 is the predominant variant in the United States, accounting for approximately 53% of new COVID-19 illnesses ¹ ². This variant is a descendant of the Omicron family and has been rising in prevalence since March, overtaking its parent lineage KP.3 and previous KP.2 variants ¹.

*Key Characteristics of KP.3.1.1:*

- _Higher Infectivity_: Preliminary evidence suggests that KP.3.1.1 may exhibit higher infectivity compared to KP.3 ².

- _Immune Escape_: KP.3.1.1 contains several mutations associated with escape from vaccine-mediated immune protection ².

- _Increased Transmissibility_: The variant is believed to have similar virological and epidemiological characteristics to KP.2, with a higher relative effective reproduction number ².

*Current COVID-19 Activity:*

COVID-19 activity remains elevated, with markers such as test positivity, emergency department visits, and hospitalizations increasing, particularly among adults aged 65 years and older and children younger than 2 years ¹.

*Vaccination and Protection:*

While vaccination is still effective in preventing severe COVID-19, research suggests that KP.3.1.1 may exhibit substantial resistance to monovalent XBB.1.5 vaccine sera ². However, being up-to-date with the COVID-19 vaccine can protect against serious illness, hospitalization, and death from COVID-19 ¹. The CDC recommends COVID-19 vaccines for all people ages 6 months and older ¹.