Published: 5 March 2020
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Influenza vaccine: Looking back on 2019 and what to expect this year
Prescriber Update 41(1): 10-11
March 2020
About one in four New Zealanders are infected with influenza each year and a proportion of these are hospitalised1. This has a significant impact on our health services.
Immunisation remains the best defence against influenza.
Looking back on 2019
Influvac Tetra was the funded vaccine for people aged 3 years and older and Fluarix Tetra was the funded vaccine for children aged under 3 years.
There were more than 1.35 million doses of influenza vaccine distributed in 2019, the highest number of doses ever delivered annually.
The Centre for Adverse Reactions Monitoring (CARM) received 229 suspected reports of adverse reactions to influenza vaccine in 2019 (Table 1), of which 2.6 percent were considered serious. A serious adverse reaction is defined as any reaction that results in death or is life-threatening, causes or prolongs hospitalisation, results in persistent or significant disability/incapacity, is a congenital abnormality or is a medically important event.
There were 550 adverse reactions described in the reports. The most commonly reported adverse reactions were injection site inflammation, arm pain, dizziness, headache and pruritus (Table 2).
The majority of reports in 2019 were submitted by nurses (68.6 percent), followed by GPs (14.9 percent) and pharmacists (9.2 percent). This reporter pattern is similar to previous years.
Table 1: Number of reports of adverse events following influenza vaccination received by the Centre for Adverse Reactions Monitoring and number of influenza vaccine doses distributed, 2015–2019
| 2015 | 2016 | 2017 | 2018 | 2019 | |
|---|---|---|---|---|---|
| Number of adverse event reports following influenza vaccination | 241 | 212 | 191 | 232 | 229 |
| Influenza vaccine doses distributeda | 1,211,152 | 1,245,934 | 1,217,169b | 1,317,197 | 1,355,666 |
| Estimated reporting rate per 100,000 doses | 19.9 | 17.0 | 15.7 | 17.6 | 16.9 |
Notes:
- The number of doses distributed is not equal to the number of people who received the vaccine.
- The 2017 influenza vaccine distribution figures were updated in 2018 and differ slightly from those previously published in Prescriber Update (medsafe.govt.nz/profs/PUArticles/March2018/seasonal-flu-vaccine-spontaneous-reports.htm). The estimated reporting rate is unchanged.
Table 2: Top five reported suspected adverse reactions for seasonal influenza vaccines, 2019
| Adverse reaction | Number |
Percentage of total reactions (n=550) |
Percentage of total reports
(n=229) |
|---|---|---|---|
| Injection site inflammation | 59 | 10.7 | 25.8 |
| Arm pain | 22 | 4.0 | 9.6 |
| Dizziness | 20 | 3.6 | 8.7 |
| Headache | 17 | 3.1 | 7.4 |
| Pruritus | 17 | 3.1 | 7.4 |
What to expect this year
The following strains will be included in quadrivalent influenza vaccines this year, as recommended by the World Health Organization2:
- A/Brisbane/02/2018 (H1N1)pdm09-like virus
- A/South Australia/34/2019 (H3N2)-like virus
- B/Washington/02/2019-like (B/Victoria lineage) virus
- B/Phuket/3073/2013-like (B/Yamagata lineage) virus.
The funded influenza vaccine is changing in 2020. Eligible children aged under 3 years will receive the Afluria Quad Junior vaccine, which contains 7.5 mcg of each vaccine strain per 0.25 mL dose (total antigen content is 30 mcg/0.25 mL)3. Eligible adults will receive Afluria Quad, which contains 15 mcg of each vaccine strain per 0.5 mL dose (total antigen content is 60 mcg/0.5 mL).
Help track influenza across New Zealand by joining FluTracking.
References
- Huang S (on behalf of the SHIVERS investigation team). 2016. Key findings – SHIVERS. Presented at the 2016 New Zealand Influenza Symposium, 2 November 2016(updated January 2017). URL: immune.org.nz/sites/default/files/Conferences/2016/NZiS2016/8%201310%2020161102%20NZiS%20SHIVERSRevisedJan2017.pdf (accessed 28 January 2020).
- Medsafe. 2019. Influenza vaccine composition 17 October 2019. URL: medsafe.govt.nz/regulatory/flu.asp (accessed 16 January 2020).
- PHARMAC. 2020. Pharmaceutical Schedule February 2020 27(0): 265–6. URL: pharmac.govt.nz/2020/02/01/Schedule.pdf (accessed 28 January 2020).
