The number of admissions to intensive care units is already more than double the number for the whole of 2012, raising fears about whether medical staff can cope.
Seven of those who developed severe complications were children.
Health Secretary Alex Neil has blamed high levels of flu along with the stomach bug norovirus for reports of chaos in Scottish hospitals this month.
Patients have had to wait on trolleys for hours because of the high number of admissions and the shortage of available beds.
Chief Medical Officer Dr Harry Burns wrote to GP surgeries just before Christmas, saying cases of flu were on the increase and giving doctors the go-ahead to prescribe anti-viral drugs to prevent or treat the symptoms.
Dr Jim McMenamin, consultant epidemiologist with surveillance agency Health Protection Scotland, said: "The last flu season [2011/12] was the lightest flu season we have had in many years. It also started later than usual. This season started earlier – more in line with what we have seen in the past. Flu consultations with GPs increased across December."
The latest figures show appointments with family doctors about flu symptoms rose from 37 per 100,000 people to 52 in the first two weeks of the year. However, in the first sign the virus may have reached its peak, the number dropped to 33 in the week ending January 20.
Mr McMenamin said: "Whether the drop is something that continues we will have to see over the coming weeks, but it is encouraging. The flu season extends almost to the middle of May. We have to keep everything under close review."
Detailed data on the impact of winter flu has been recorded by Health Protection Scotland for three years. In 2010-11, 177 patients needed intensive care treatment for flu complications and 63 people died. Last year this dropped to 17 intensive care admissions and five deaths.
Mr McMenamin said nine deaths so far this year was proportionally a slightly lower toll than last year or the previous winter. Most of the victims were elderly.
He added: "It is really important everyone does whatever they can to prevent the spread of infection. The one thing you can do is have good cough and hand hygiene. Cover your nose and mouth with a handkerchief if you are coughing or sneezing, dispose of that tissue promptly and wash your hands as soon as you can."
He said most patients can look after themselves when they are unwell by taking paracetamol and plenty of fluids, but people in the at-risk groups, including pensioners and those with long-term health problems, should consider seeing their GP.
Dr McMenamin said it was not too late for people who qualify for free flu vaccines to take up the offer. Pensioners and patients with longterm health conditions such as asthma are among those eligible.