Influenza and other special patient groups

Immune compromised

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 radiation treatment. When this is not possible, influenza vaccination is
recommended and can be given while an individual is receiving treatment. 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 following haematopoietic stem cell or solid organ transplantation.

Regardless of their age, in the first year of being immune compromised/immunosuppressed individuals are recommended to receive two doses of influenza vaccine administered four weeks apart. Then in subsequent years, only one dose required.54
As the response to influenza vaccination in those with a poorly functioning immune systems is likely to be low, additional preventative strategies are important. Influenza vaccination is recommended (although not funded) for those who are in close
contact with individuals at high-risk of complications to reduce the risk of spread of the disease to those who are more vulnerable and also may be less likely to mount a strong immune response to the vaccine.

International travel

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 vaccine. 

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 haven’t been immunised in the proceeding autumn or winter or it is getting close to 6–8 months since their last influenza vaccination, repeat vaccination is recommended prior to travel. However, depending on stock, influenza vaccine may not be available for private 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
Northern hemisphere influenza vaccine for
Trivalent vaccines
• A/Michigan/45/2015 (H1N1)pdm09-like virus
• A/Hong Kong/4801/ 2014 (H3N2)-like virus
• B/Brisbane/60/2008-like virus

Quadrivalent vaccines will also include
• B/Phuket/3073/2013-like virus

Trivalent vaccines
• A/California/7/2009 (H1N1)pdm09-like virus
• A/Hong Kong/4801/2014 (H3N2)-like virus
• B/Brisbane/60/2008-like virus

Quadrivalent vaccines will also include
• B/Phuket/3073/2013-like virus

Note: these strains are the same as for the Southern hemisphere influenza vaccine for 2016.

Are there any circumstances where people may consider re-immunising 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 re-vaccination prior to travel.

Protective antibodies peak one week to one month after vaccination and then begin to wane.

By 6-8 months after vaccination, protective levels are lower and may not be sufficient to provide good protection.