Earlier this week Scotland’s health secretary warned that flu cases were expected to spike over the coming weeks.
Neil Gray said rates were following a similar trend to last year after Public Health Scotland (PHS) figures showed that cases had doubled in the week ending 30 November.
Gray urged those eligible for a vaccine to take up the offer and encouraged anyone who can afford a private vaccine to do so.
Hospitals in NHS Greater Glasgow and Clyde and the Western Isles have asked staff and visitors to wear face masks at all times when on wards.
The health boards said it was a precautionary measure to reduce the risk of infection and protect patients and visitors.
More than 700 people were hospitalised because of the illness between 24-30 November, according to PHS’s viral respiratory diseases surveillance report, external.