Millions of Americans contracted COVID-19 amid the omicron-driven surge, spurring hope that national immunity would shore up and help prevent additional surges in the future. However, infection-induced immunity from omicron may not persist long enough to build a sufficient immunity wall against subsequent infection.
"What we saw with previous variants was that immunity persisted for a longer period of time," Scott Gottlieb, MD, former FDA commissioner and member of Pfizer's board, told CNBC Feb. 2. "What we are seeing with omicron — now there is pretty good evidence around this … [is] it appears the immunity conferred by infection from omicron isn't that durable," he said, citing a number of studies.
Immunity after an omicron infection likely lasts at least three months and "probably upward of six months, but eventually the antibodies do wane," Dr. Gottlieb said. Protection against disease severity will still linger, though reinfection itself is likely.
Right now, the "best speculation" on why infection-induced immunity from omicron isn't durable is because it's more of an upper airway infection, he said.
"We see less durable immunity in upper airway infections, and it's less virulent; since it's less of a severe infection, it's not inducing as robust of an antibody response," Dr. Gottlieb said.