More than 85 percent of Indonesia's population has antibodies against Covid-19, a government-commissioned survey showed, but epidemiologists warned it was not clear whether this immunity could help contain a fresh wave of coronavirus infections.

The survey, conducted between October and December by researchers at the University of Indonesia, found Indonesians had developed antibodies from a combination of Covid-19 infections and vaccinations.

Pandu Riono, an epidemiologist...