Post-infection immunity is similar or even superior to the protection bestowed by COVID-19 vaccines, according to a new study.
Post-infection protection—known widely as natural immunity—was strong and remained significant over time, researchers found. Against the Wuhan, Alpha, and Delta variants, the protection against re-infection was 85 percent at four weeks, 78 percent at 40 weeks, and 55.5 percent at 80 weeks.
That protection dropped more quickly against the Omicron BA.1 subvariant, declining to 36 percent by 40 weeks, and protection against symptomatic disease also waned below 50 percent.
But shielding against severe disease was strong against all strains, including the BA.1 subvariant, researchers found. The naturally immune enjoyed 88.9 percent protection against BA.1 at 40 weeks, which was actually higher than against earlier strains….