Discussion Document for Consideration on the Best Time to Start the Annual Influenza Immunisation Pr

Discussion document for consideration on the best time to start the Annual Influenza Immunisation Programme Summary This discussion paper considers options and provides a recommendation on the best time to start the Annual Influenza Immunisation Programme (the Programme). The paper discusses recent research on the decline of influenza vaccine effectiveness (VE), influenza surveillance, the international context and considers the implications of a change in the timing of the Programme on service delivery.

The options for consideration are: 

Status Quo: maintain the status quo and start the Programme as soon as the vaccine becomes available in early to mid-March each year



Preferred Option: move the timing of the Programme to start from 1 April each year.

What we need from you?   

We are seeking your feedback on the best time to start the Programme.

Take the time to consider the discussion below and answer the questions provided at the end.

Please email your responses to immunisation@moh.govt.nz by 10 August 2018.

Background Influenza can cause severe illness and secondary complications can lead to hospitalisation and death in high risk groups, including young children, older people, pregnant women and those with a range of underlying medical conditions. 1, 2 However, sometimes even healthy children and adults can also be at risk of serious illness following influenza infection. Māori and Pacific people and those from lower income groups experience a higher burden of disease from influenza.3, 4 On average, approximately 400 deaths are attributed to influenza and its complications annually.2 Each year, seasonal influenza impacts on population health and the health system, causing increased demand for health services, including general practice visits and hospitalisations, especially for those at greater risk from the complications from influenza.1 The impact of influenza in New Zealand is substantial on the health of the population and health sector.3 The highest burden of disease is in the very young, older people, pregnant women, those with underlying medical conditions, people from low income groups, and Māori and Pacific peoples.3, 4 The influenza vaccination is the most effective preventative measure to protect those at risk from influenza and its complications.1 Influenza vaccination prevents the spread of

disease, reducing the chance of passing on the influenza virus to those in high risk groups.1,2,5 Factors that impact on vaccine effectiveness (VE) VE is affected by the influenza vaccine’s match to circulating influenza virus strains, vaccine characteristics, and other host factors such as the individual’s age, underlying medical conditions and time since vaccination.5,8 During seasons where the vaccine strains closely matches the circulating strains, VE can be as high as 80 to 90 percent in healthy adults. 5-9 The World Health Organization (WHO) annually selects the vaccine strains for the Northern and Southern Hemisphere influenza seasons to match the most recent circulating strains.6 International research on vaccine effectiveness New research shows that protection begins to decline after vaccination.5 Maximum protection is observed shortly after vaccination and starts to decline by about 7 percent every month. 6-8 Studies from the United Kingdom (UK), Canada and Australia show that VE against influenza strains A and B declines significantly after 6 months.9-12 VE decline is more prominent and rapid in those aged 65 and older and the very young in comparison to healthy adults.5-7 Optimal time to vaccinate against influenza An understanding of VE and the duration of protection helps to determine the optimal time to vaccinate, as vaccinating too early ahead of the influenza season may substantially reduce protection during the peak of the influenza activity. 5-9 This decline in VE may cause increases in overall incidence of influenza and associated outbreaks (particularly in aged care residential facilities) as well as increase hospitalisations and deaths.

Delaying vaccination might result in greater immunity later in the season, but such deferral might also result in missed opportunities to vaccinate, as well as increasing the pressure on service providers to vaccinate the population in a shorter time period before winter hits.

Community vaccination programmes should balance maximizing vaccine-induced protection through the season with avoiding missed vaccination opportunities, undue pressure on vaccinators, or vaccinating after onset of influenza circulation occurs.11,12 Asymptomatic carriers The majority of influenza infections are asymptomatic, with most symptomatic cases self-managing without seeing their general practitioner. Results from the 2015 Southern Hemisphere Influenza and Vaccine Effectiveness, Research and Surveillance (SHIVERS) serosurvey showed that around 26 percent of people in New Zealand had contracted influenza over the 2015 season.13 Approximately 80 percent of infected people (4 in 5 infected) were asymptomatic, with only 2.5 percent (1 in 40) of those infected visiting their GP and 0.2 percent (1 in 560 infected) hospitalised.13 Asymptomatic carriers are still infectious and can spread the virus among their family, co-workers, classmates and patients without realising it.13 Page 2 of 8

Impact of influenza on high risk groups and government priorities Achieving equity and delivering equitable health outcomes is a government priority. It is imperative that preventative measures such as high vaccination coverage reach New Zealanders who are most at risk and experience inequitable health outcomes.

Health inequities exist in the burden of influenza. The groups with highest influenza mortality and hospitalisations are people aged 65 and older, children under one year and Māori and Pacific peoples.

New Zealand’s Annual Influenza Immunisation Programme Influenza seasons vary in timing and duration.1 Surveillance data shows that the New Zealand influenza season typically runs from May to September and peaks around July (refer to Figure 1).4 However, in recent years the peak has moved to August, which was the rationale for extending the end of the funded Programme until 31 December each year.

Based on current surveillance data, the shift in peak influenza activity and the decline in VE support a change to the timing of the start of the Programme, for example to early April.

Influenza programmes need to start before the onset of the influenza season, and the vaccine takes up to two weeks to become effective. Any change to the Programme’s start date will need to be considered alongside the implications for service delivery.

Figure 1. Weekly general practice consultation rates for influenza like illnesses

Source: ESR

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Status Quo The Programme traditionally started in late February/early March and continued to 31 July. In recent years the Programme has been extended due to the influenza peak not being reached until late July/August. From 2017 onwards, the Programme end date was moved to 31 December to ensure high risk groups, especially pregnant women or those who were not vaccinated earlier in the year, continue to have access to protection against influenza even as activity decreases.

There have been years where the Programme has started late due to a delay in vaccine manufacture associated with a strain change. In 2018, the Programme did not start until early April and in 2015, the Programme started 26 March. Delays in vaccine manufacture associated with a strain change cannot be predicted.

International Influenza Immunisation Programmes Influenza activity is not usually significant in the United Kingdom (UK) before the middle of November. They recommend vaccination take place between September and early November and completed by the end of November.14 In the UK, protection afforded by the vaccine is thought to last for at least one influenza season, however annual revaccination is recommended.14 The Canadian influenza season usually occurs between November and April. 15 Most adults (75 percent) are vaccinated during October or November. Based on the information sourced on the UK and Canadian programmes they do not appear at this stage to have considered the impact of declining VE on the best time to start influenza vaccination.

Since 2017, Australia has chosen not to start their influenza programme until early April to accommodate the timing of their influenza season, April to October.16 The period of peak influenza circulation is typically June to September for most parts of Australia. The Australian Technical Advisory Group on Immunisation (ATAGI) Influenza Position Statement notes that where vaccine protection is generally expected to last for the whole season, optimal protection against influenza occurs within the first 3 to 4 months following vaccination.16 Analysis of options

Status quo

Options

Pros

Cons

Programme starts when vaccine is available approximately February/March. Approximately three months prior to the influenza peaks during JulyAugust.

If individuals are vaccinated in February/March they may not have optimal protection against influenza during the July-August seasonal peaks.

Allows more time for primary care to vaccinate their at risk populations prior to the start of the season.

Those most at risk from the complications of influenza (ie very young and older people) are most affected by a decline in VE.

Implications on service delivery No change to current programme. Could still promote that the best time to be vaccinated to ensure individuals are protected during the peak of the influenza season (ie, 3-4 months before July-August).

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General practice patients, especially the older population are used to being vaccinated early enabling practices to plan their vaccine recall once the bulk of patients have already been vaccinated.

No certainty with regards to start date can be given to general practices and vaccinating pharmacies to enable them to better plan their influenza immunisation programmes.

Aligns with the commencement of the private sector occupational health influenza immunisation programmes, which tend to start as soon as the private vaccines are made available (usually just prior to the funded vaccine).

Starting the influenza programme on or around 1 April would allow for optimal VE during the peak of the influenza season, especially for those at greater risk from influenza (ie, older people).

1 April Preferred Option

Supported by evidence of VE decline with time since vaccination.

Certainty can be given to general practices and vaccinating pharmacies that the vaccine will be available on this date enabling them to better plan their influenza immunisation programmes.

Aligns with the delivery of most DHB healthcare worker influenza immunisation programmes – which do not routinely start until April.

One less month for general practices to vaccinate their at risk populations before the peak of the influenza season in July-August.

Consultation is required with the key stakeholders to identify the implications or any unintended consequences of moving to a later start date.

Communication strategy providing the rationale for this change will need to be circulated as soon as practicable before the end of the year to enable general practices time to plan their programmes and inform their patients.

This change in start date will enable more time for training and preparation of vaccinators and immunisation coordinators will be able to build vaccinator capacity. This is turn will relieve immunisation services of any undue pressures.

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Questions for your feedback:

1. Please comment or provide your views on your preferred start date for the Influenza Immunisation Programme 2. Do you agree with the Ministry’s preferred option to start the Influenza Immunisation Programme on 1 April, if not, why not?

3. What implications do you think commencing on 1 April will or may have?

4. Do you have any other comments on the discussion paper?

Please email your responses to immunisation@moh.govt.nz by 10 August 2018.

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References 1. Ministry of Health. Immunisation Handbook 2017 (2nd ed). Wellington: Ministry of Health; 2018, 279 p.

2. Centers for Disease Control and Prevention. Prevention and control of seasonal influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices – United States, 2016–17 influenza season. Morbidity and Mortality Weekly Report: Recommendations and Reports 65(RR05) [Internet]. 2016. [cited 2018 May 15]. Available from https://www.cdc.gov/mmwr/volumes/65/rr/rr6505a1.htm 3. Khieu, TQT. Estimating the health burden of influenza in New Zealand [New Zealand]. University of Otago, New Zealand. 2017. [cited 2018 May 21].

Available from http://hdl.handle.net/10523/7634 4. Institute of Environmental Science and Research Ltd. Influenza Surveillance in New Zealand 2016. [cited 2018 May 21]. Available from https://surv.esr.cri.nz/PDF_surveillance/Virology/FluAnnRpt/InfluenzaAnn2016.pd f 5. Young B, Sadarangani S, Jiang L, Wilder-Smith A, Chen MI. The Duration of Influenza Vaccine Effectiveness: A Systematic Review, Meta-analysis and Metaregression of Test-Negative Design Case-control Studies. J Infect Dis. 2017 Dec 6.

6. World Health Organization. Influenza (Seasonal). 2018 January [cited 2018 May 15 ] Available from http://www.who.int/mediacentre/factsheets/fs211/en/ 7. World Health Organization. Recommended Composition of Influenza Virus Vaccines For Use in the 2018 Southern Hemisphere Influenza Season. 2018 September [cited 2018 May 15] Available from http://www.who.int/influenza/vaccines/virus/recommendations/201709_recomme ndation.pdf?ua=1 8. Belongia EA, Sundaram ME, McClure DL, Meece JK, Ferdinands J, VanWormer JJ. Waning vaccine protection against influenza A (H3N2) illness in children and older adults during a single season. Vaccine [Internet] 2015 [cited 2018 May 15]; 33:246–51. Available from http://dx.doi.org/10.1016/j.vaccine.2014.06.0522 9. Ferdinands JM, Fry AM, Reynolds S, Petrie JG, Flannery B, Jackson ML, Belongia EA. Intraseason waning of influenza vaccine protection: evidence from the US Influenza Vaccine Effectiveness Network, 2011–2012 through 2014– 2015. Clin Infect Dis [Internet]. 2017 Mar [cited 2018 May 15]; 64(5):544-50.

Available from https://doi.org/10.1093/cid/ciw816 10. Kissling E, Nunes B, Robertson C, Valenciano M, Reuss A, Larrauri A, Cohen JM, Oroszi B, Rizzo C, Machado A, Pitigoi D. I-MOVE multicentre case–control study 2010/11 to 2014/15: Is there within-season waning of influenza type/subtype vaccine effectiveness with increasing time since vaccination?. Euro Surveill [Internet]. 2016 Apr 21 [cited 2018 May 21]; 21(16). Available from https://www.ncbi.nlm.nih.gov/pubmed/27124420 11. Sullivan SG, Komadina N, Grant K, Jelley L, Papadakis G, Kelly H. Influenza vaccine effectiveness during the 2012 influenza season in Victoria, Australia: influences of waning immunity and vaccine match. J Med Virol. 2014 Jun 1 [cited 2018 May 21]; 86(6):1017-25. Available from https://www.ncbi.nlm.nih.gov/pubmed/24395730 DOI 10.1002/jmv.23847 12. Pebody RG, Andrews N, McMenamin J, Durnall H, Ellis J, Thompson CI, Robertson C, Cottrell S, Smyth B, Zambon M, Moore C. Vaccine effectiveness of 2011/12 trivalent seasonal influenza vaccine in preventing laboratory-confirmed Page 7 of 8

influenza in primary care in the United Kingdom: evidence of waning intraseasonal protection. Euro Surveill [Internet]. 2013 Jan 31[cited 2018 May 21]; 18(5):20389.

13. Southern Hemisphere Influenza and Vaccine Effectiveness Research and Surveillance. Key findings Huang S (on behalf of the SHIVERS Investigation team). 2016. Presented at the 2016 New Zealand Influenza Symposium (updated January 2017) [Internet]. [cited 2018 May 25] Available from http://www.immune.org.nz/sites/default/files/conferences/2016/NZiS2016/8%201 310%2020161102%20NZiS%20SHIVERSRevisedJan2017.pdff 14. National Health Service England. The national flu immunisation programme 2018/19 [Internet]. Leeds, England. 2018 Mar 26 [cited 2018 May 21] Available from https://assets.publishing.service.gov.uk/government/uploads/system/uploads/atta chment_data/file/694779/Annual_national_flu_programme_2018-2019.pdf 15. NACI. Canadian immunization guide chapter on influenza and statement on seasonal influenza vaccine for 2017–2018 [Internet]. Public Health Agency of Canada; 2017. [cited 2018 May 15] Available from https://www.canada.ca/en/public-health/services/publications/healthyliving/canadian-immunization-guide-statement-seasonal-influenza-vaccine-20172018.html 16. Australian Technical Advisory Group on Immunisation. ATAGI advice on seasonal influenza vaccines in 2018 [Internet]. 2018 Mar 20 [cited 2018 May 15].

Available from https://beta.health.gov.au/resources/publications/atagi-advice-onseasonal-influenza-vaccines-in-2018

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