The Scottish Government said it expects the flu to be the predominant strain and is urging those most at risk – including the elderly and pregnant women – to get vaccinated.
There was an outbreak of the H1N1 virus – known as swine flu because the virus is similar to a type which affects pigs – in summer 2009.
It caused more than 14,000 deaths across the world and around 360 in the UK.
Professor Hugh Pennington, an expert in bacteriology, warned that a new outbreak could be more lethal than last year’s pandemic.
He told a newspaper: “The past is the guide to the future with flu and with all pandemics there have been subsequent waves which have been hotter and nastier and killed more people.
“In 1918-19 for example when 50 million people died of H1N1, the second wave was much more serious than the first.
“A lack of scientific evidence means we do not know and are never likely to know whether this was because of a mutation or because it attacked people who were not affected first time round.”
A Scottish Government spokeswoman said: “It is expected that H1N1 will be the main flu virus circulating during the 2010-11 season. Most people will recover from flu naturally within a week.
“However, those with health conditions, including heart and lung problems, are at an increased risk of experiencing serious complications as a result of flu. These people are encouraged to receive vaccination to protect themselves.”
The Press Association