The Mamawetan Churchill River Health Region says the advisory is a precaution and covers 19 people given shots for tetanus, diphtheria and whooping cough at the La Ronge Health Centre.
The vaccinations were done after a prolonged power outage in June.
Andrew McLetchie, the health region's CEO, says refrigeration in the hospital's emergency and acute-care areas was affected when an emergency power supply failed to kick in.
The advisory does not cover people who received vaccinations from the centre's public health office.
McLetchie says the vaccine given to the 19 people won't harm them, but it may not be effective. (CJLR)