Asia did mask up for SARS-1. And the masks did help. WHO was slow back then, too.
You’ve just forgotten.
Sample:
WELCOME TO THAILAND
On landing, therefore, it was rather a surprise to find all staff in Bangkok airport wearing surgical masks, including customs officials, cleaners, and police. Many passengers were shocked and began to worry, as there had been no information given on the incoming flight. The masks being used were quite basic and not of the specification recommended by the WHO for use when caring for a SARS patient.
7
There was no reported transmission of SARS in Thailand at this point, although there had been seven cases and two deaths associated with travel from infected areas. We asked a policeman about the masks and were told that the Health Ministry had ordered use of surgical masks in the airport.