Sweden, which was criticized for its decision not to enforce a nationwide stay-at-home order, is expected to reach “herd immunity” in its capital within weeks.

The country’s plan to allow some exposure to the virus, while protecting groups at high risk, in hopes of building immunity in the general population is expected to soon reach a successful benchmark in the capital of Stockholm, Anders Tegnell, an epidemiologist at Sweden’s Public Health Agency, told CNBC on Tuesday.