Influenza surveillance update

Media Release

16 July 2001

Influenza surveillance update

THE predicted spate of influenza moving through New Zealand this winter has reached the South Island over the past two weeks according to latest statistics.

Statistics also show that the national number of consultations for influenza-like illness (ILI) has decreased.

In the week ending July 6 the national consultation rate of 96 cases of ILI per 100,000 people was considerably lower than in the preceding week. In the week ending June 29 about 140 cases per 100,000 people were reported by the general practitioners influenza surveillance network.

National Influenza Immunisation Strategy Group member and virologist Dr Lance Jennings said there were several possible reasons for the apparent decreasing influenza activity nationally.

"Last year was a particularly mild influenza-year and the virus was circulating for over 6 months, far longer than the usual six to eight week season. A large number of people would have been exposed to the A/New Caledonia virus during this period. The same virus is circulating this year so many people will already be immune to it."

"The recent two-week school holiday period has also reduced the opportunity for the virus to spread as children are often the spreaders of influenza viruses in the community. In addition, the stable spell of weather may have been a contributing factor."

In the week ending July 6 there were 302 consultations for ILI reported from 79 general practices in 23 out of 24 health districts. The week before there was a total of 447 ILI consultations reported from 81 general practices in 23 out of 24 health districts.

Eastern Bay of Plenty had the highest consultation rate (350 people per 100,000) followed by Wairarapa (265 per 100,000).

As predicted, numbers of ILI cases reported in the South Island are starting to increase. South Canterbury went from about 45 cases per 100,000 in the week ending June 29 to about 130 people per 100,000 in the week ending July 6. Nelson Marlborough went from about 60 cases per 100,000 to 90 cases per 100,000 and the West Coast went from 50 cases per 100,000 to 100 cases per 100,000.

The Ministry of Health encouraged those who would be at greatest risk following a bout influenza to be immunised before this year's influenza season took hold.

Figures show approximately 156 people per 1000 took the Ministry's advice.

"Overall, this is about 16 percent of New Zealand's population. Although the spread of influenza in the community is unlikely to have been affected, vaccination will have reduced the dangers for many elderly or people with existing medical conditions."

ENDS

For more information contact Hayley Brock, Media Advisor (04) 496 2115, 025 495 989 www.moh.govt.nz

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