The Ministry of Health expects an early start to the 2010 influenza season, following an early start in the northern hemisphere, with the number of cases expected to begin rising over the next couple of weeks, into early May. However, as in the northern hemisphere, the rise is expected to be more gradual than last year and fewer cases are expected overall. This is partly due to the proportion of the community exposed to the H1N1 pandemic strain last year, estimated at around 30%, according to Christchurch virologist Lance Jennings. Like last year, the H1N1 strain is expected to predominate this season. Supplies of this year’s seasonal influenza vaccine, normally delivered from Paris, may be disrupted over the next week by the European flight cancellations caused by the Icelandic volcanic ash plume. The situation is being monitored. More than 772,000 doses of flu vaccine have been distributed so far this season - more than the entire 2008 flu season and 17% more than by this time last year. The ministry has also told New Zealand Doctor newspaper that it has made changes to its antiviral medicines policy so that people with a prescription for Tamiflu (oseltamivir) or Relenza (zanamivir) can get hold of the drugs more quickly this year. These drugs are used to lessen or shorten the symptoms of flu in those who catch the infection.