Influenza and other special groups
Individuals who are immune compromised are at high risk of severe influenza and complications. It is important to offer vaccination prior to the initiation of chemotherapy or immune suppressant medication. When this is not possible, influenza vaccination is recommended and can be given while an individual is receiving most treatments, please refer to page 16 of the Flu Kit Booklet 2019 for advice on cancer treatments when influenza vaccination may be contraindicated. Two doses of vaccine administered four weeks apart are recommended in all age groups undergoing chemotherapy. Following cessation of chemotherapy, normal immune responses return after about 30 days.
Specialist's advice should be sought when considering influenza vaccination of individuals who have received a haematopoietic stem cell or solid organ transplantation in the preceding six months.
Protection against influenza may be improved in some individuals with immunosuppression, regardless of their age, after receipt of a second influenza vaccination a minimum of four weeks after the first. The second influenza vaccination is only funded for children aged 6 months to under 9 years when influenza vaccine is being used for the first time.
As the response to influenza vaccination in those with a poorly functioning immune system is likely to be low, additional preventative strategies are important to reduce their exposure to influenza. The vaccination is also recommended, although not funded, for those who are in close contact with individuals who are more vulnerable or at high risk of complications. Front-line healthcare workers are usually funded by their employer.
Studies have indicated that influenza is the most commonly contracted vaccine preventable disease amongst international travellers. Influenza outbreaks have been linked to travellers. Certain types of travel where large numbers of people are likely to be in close proximity, such as cruise ship voyages or events that include mass gatherings are particularly high risk.
For these reasons, all people travelling outside New Zealand should consider influenza vaccination pre-travel. This is especially important for those who are at higher risk of influenza complications, many of whom will be eligible for subsidised vaccination.
In tropical countries, influenza activity can occur throughout the year, so vaccination is worthwhile regardless of season. In temperate climates in the Northern Hemisphere activity is more common between the months of December and March.
If a traveller has received the Southern Hemisphere vaccine in the preceding New Zealand autumn or winter and the same strains are circulating in the Northern Hemisphere, they should remain protected.
If they have not been vaccinated in the proceeding autumn or winter or it is getting close to 6 months since their last influenza vaccination, repeat vaccination is recommended prior to travel. However, depending on stock, influenza vaccine may not be available for purchase far beyond the funded time period. Anyone receiving an influenza vaccination outside the funded period will need to pay. If the Southern and Northern Hemisphere vaccine strains differ significantly, it would be preferable to obtain the local vaccine on arrival. However, vaccination with the Southern Hemisphere vaccine may offer some protection and would be preferable to having no vaccine. The Northern Hemisphere vaccine is not available in New Zealand.
Southern Hemisphere vaccine vs Northern Hemisphere vaccine
Southern Hemisphere influenza vaccine for 2019
Northern Hemisphere influenza vaccine for 2018–2019
Are there any circumstances where people may consider re-vaccinating within a year, e.g. prior to travel?
Yes. When the available vaccine gives protection against influenza viruses circulating in the Northern Hemisphere, travellers – particularly those in ‘high-risk’ groups – who will be exposed to a Northern Hemisphere influenza season should consider vaccination or repeat vaccination prior to travel.194 However, re-vaccination prior to travel is not funded.
Protective antibodies peak one week to one month after vaccination and then begin to wane. By 6 months after vaccination, protective levels are lower and may not be sufficient to provide good protection.