Hybrid immunity: COVID vaccination, infection offers highest protection against severe disease

With omicron subvariants continuing to increase across the nation, people who are vaccinated against COVID-19 and had a previous infection have the highest level of protection against severe disease and hospitalization, according to a study by the World Health Organization.

WHO officials released a report published in “The Lancet Infectious Diseases” this week, revealing that developing hybrid immunity – a combination of immunity through vaccination and an infection – was more than 97 percent effective against “hospital admission or severe disease” after a year.

But those who are unvaccinated with a previous COVID infection had a lower level of protection against severe disease and hospitalization, the study found. Those with just a previous infection after 12 months had around 74 percent effectiveness against severe disease or being admitted to the hospital.

As to those with hybrid immunity, protection waned to about 42 percent against getting reinfected with COVID after a year following “primary series vaccination,” according to the study.

Meanwhile, a more transmissible omicron subvariant called XBB.1.5 had accounted for about a half of new cases in the United States, federal health officials reported Friday.

The federal Centers for Disease Control and Prevention (CDC) showed XBB.1.5 made up 49.1 percent of new infections. That represents an increase since last week when the subvariant accounted for around 37 percent of infections.

Maria Van Kerkhove, an epidemiologist who serves as the COVID-19 technical lead for the WHO, said in early January that XBB.1.5 is the most transmissible version of the omicron variant, as previously reported by the Florida Phoenix.