to shut in; to confine (in); to seal in; to trap
to contain; to suppress; to restrain; to bring under control
秘密を封じ込める方法を考えた。
I thought of a way to seal in the secret.
ウイルスを封じ込める。
They contain the virus.
感染拡大を封じ込めた。
They contained the spread of infection.