The influenza immunisation programme is starting early in 2020

Immunisation is the best protection against influenza

The influenza immunisation programme commenced on 18^th March, 2020, for people eligible for funded vaccines and healthcare workers (subject to vaccine availability). People who are not eligible for funded influenza vaccinations should be asked to defer vaccination until on or after 13th April, 2020.

This change was made in response to the current situation with the COVID-19 (novel coronavirus) pandemic. Increasing influenza vaccination rates in vulnerable patient groups and healthcare workers is a priority. An additional 400,000 doses of influenza vaccine have been ordered in 2020 in anticipation of demand based on the experience of last year. Over 1.35 million doses of influenza vaccine were distributed in New Zealand during the 2019 season, more than any previous year,¹ and an additional 55,000 doses were obtained mid-season.²

Four strains of influenza are included in the 2020 vaccine

The 2020 influenza vaccine includes four strains of inactivated influenza virus, of which three are new:³

• B/Phuket/3073/2013-like virus
• A/Brisbane/02/2018 (H1N1)pdm09-like virus^*
• A/South Australia/34/2019 (H3N2)-like virus^*
• B/Washington/02/2019-like virus^*

^*Not included in the 2019 influenza vaccine

Vaccine selection is determined by age

Two influenza vaccines are subsidised for the 2020 season:⁴

• Afluria Quad is approved for use in adults and children aged three years and over and is funded for eligible people in this age group (see below)
• Afluria Quad Junior is approved for use in children aged six months to 35 months and is funded for eligible children in this age group

The Afluria Quad vaccine began being distributed on 16th March, 2020. The Afluria Quad Junior vaccine is expected to be available from 1st April, 2020.
Afluria Quad is given as a single, 0.5 mL dose and Afluria Quad Junior is given as a single, 0.25 mL dose.⁴ Children aged six months to nine years, however, who are receiving an influenza vaccine for the first time should receive two doses, at least four weeks apart.⁴ Both vaccines are contraindicated in children aged less than six months due to a lack of safety and efficacy data in this age group.⁴

People who are eligible for free influenza vaccinations

People who are eligible for funded influenza vaccinations are at the greatest risk of serious illness this season and vaccinating this group as soon as vaccines are available should be regarded as the highest priority for practices. This group of people includes:^*

• Women who are pregnant
• People aged 65 years and over
• People aged under 65 years with:
  • Cardiovascular morbidity – excluding hypertension or dyslipidaemia without end-organ disease
  • Diabetes
  • Asthma who are taking preventative treatment
  • Other long-term respiratory disease such chronic obstructive pulmonary disease
  • Chronic kidney disease
  • Any cancer†
  • Autoimmune disease or immunosuppression
• Children aged under four years or under with a history of significant respiratory illness or hospitalisation for respiratory illness

^*A full list of conditions and criteria that qualify a person for a funded vaccination is available from: https://schedule.pharmac.govt.nz/ScheduleOnline.php?osq=influenza+vaccine

†Influenza vaccination may be contraindicated in patients taking immune checkpoint inhibitors. If a patient is taking atezolizumab, ipilimumab, nivolumab or pembrolizumab, contact the prescribing oncologist or 0800 IMMUNE for advice before administering the vaccine.

It is important that all people aged 65 years and over are offered the annual influenza vaccination, particularly older patients of Māori and Asian ethnicity. Guidance from the Ministry of Health (MOH) is that immunisation rates for these groups are notably lower than in other ethnic groups.

The safety of the influenza vaccine

The influenza vaccine is typically well tolerated. Adverse reactions to the vaccine are more frequent in children who have not previously been exposed to the vaccine or influenza virus.⁵ The most common adverse reactions associated with the administration of inactivated influenza vaccines are:³

• Injection site pain, erythema or swelling
• Headache, muscle ache and fatigue in adults
• Fever, irritability and loss of appetite, more commonly in children

Local and systemic adverse effects are generally mild and resolve within a day or two.³

Paracetamol or any other antipyretic medicine is not recommended before or after the influenza vaccination, in the absence of pain or discomfort, as it may lower the patient’s initial immune response.⁶ In children, paracetamol may be considered if the child is in pain, has a fever, or is distressed following the vaccination.⁶

Febrile convulsions have been associated with influenza vaccination in children, but only when it is given in combination with other vaccines, e.g. the pneumococcal vaccine.⁷ In combination with other vaccines, the influenza vaccine may increase the risk of a febrile convulsion by 16-30 per 100 000 children vaccinated.⁷ The influenza vaccination given in isolation does not increase the rate of febrile convulsions, which occur in approximately 5% of all children by age seven years.⁷

Anaphylaxis is the most serious adverse event associated with influenza vaccination.³ This generally occurs within minutes of administration, once in approximately one million vaccine doses.³ Patients who have received the influenza vaccination should be observed for 20 minutes following administration^*,³ although rarely severe allergic reactions to the vaccine may begin after this time.⁸ People with latex allergies can be safely given the influenza vaccine as the Afluria Quad and Afluria Quad Junior vaccines are both latex free.³

^* In light of the COVID-19 pandemic, this requirement may be relaxed for adults and adolescents who meet certain criteria, if the risk of infectious disease transmission is greater than the low risk of anaphylaxis. See the IMAC statement for further information: no longer available online; this information has now changed, see Bulletin 72.”

People with egg allergy can be given the Afluria Quad vaccines

The 2020 influenza vaccine can be safely given to people with a history of egg allergy, contrary to what is stated on the vaccine’s data sheet.³ The Afluria Quad and the Afluria Quad Junior vaccines are grown in hens’ eggs, however, the residual dose of ovalbumin in the vaccines is less than the one microgram necessary to trigger anaphylaxis in sensitive individuals.³

Annual influenza vaccination is recommended

There are two primary reasons for recommending annual influenza vaccination:³

• The strains of influenza virus in circulation change over time and the seasonal vaccine is adjusted in response
• The protection provided by an influenza vaccination reduces over time

Some level of protection from influenza is expected from four days post-vaccination, however, it may take up to two weeks for maximal immune response.³

The effectiveness of an influenza vaccine is determined by the degree to which the circulating strains of the virus match the vaccine, and by the health, immune status and age of the recipient.³ From 2012 to 2015, the effectiveness of the seasonal vaccination at preventing presentations of influenza-like illness in primary care and preventing influenza-related hospitalisations was estimated to be around 50%.³ Effectiveness is expected to be higher for healthy children and adults and lower for frail elderly people and those with significant co-morbidities. An additional potential benefit of vaccination is that it may provide some protection against some strains of influenza virus that are not included in the vaccine. For example, a large study found that the 2009 trivalent inactivated seasonal influenza vaccine administered in New Zealand provided a moderate level of protection against the H1N1 strain that caused the 2009 pandemic, even though that strain was not included in the 2009 vaccine.⁹

Approximately 80% of people who become infected with influenza are asymptomatic and can unknowingly risk infecting other people who might be particularly vulnerable to influenza-related complications.³

Immunisation rates need to improve in healthcare workers

One of the primary goals of the influenza immunisation programme is to annually vaccinate at least 80% of healthcare workers.³ The percentage of health care workers in New Zealand who received the influenza vaccination increased from 68% in 2018, to 73% in 2019.¹⁰ Employers of healthcare workers should actively promote staff influenza vaccinations and healthcare workers should be proactive in getting vaccinated.

Annual vaccination decreases the rate of influenza complications in older people

People aged over 65 years who receive the annual influenza vaccination are less likely to be hospitalised or require admission to an intensive care unit due to complications of influenza. ¹¹ Influenza vaccination is estimated to reduce the risk of pneumonia by 23% for older people living in the community and by 53% for frail older people living in residential care.¹¹ The risk of major cardiovascular events in older people who develop influenza is also reduced by 36% through annual influenza vaccinations.¹¹

Pregnancy increases the risk of influenza complications

The benefits of influenza immunisation should be reinforced to all women who are pregnant or considering becoming pregnant. Pregnant women who receive the influenza vaccine at any stage of pregnancy, and their babies, are significantly less likely to develop influenza or its complications, for up to six months post-vaccination.¹²

Pregnant women who develop influenza are five times more likely to be hospitalised as non-pregnant women who contract influenza, with the risk of hospitalisation increasing as gestation progresses.¹² The risk of hospitalisation increases if the pregnant woman has co-morbidities such as asthma, diabetes or cardiovascular disease.¹²

Further information about the 2020 seasonal influenza vaccination programme is available from The Immunisation Advisory Centre:

• For health professionals www.influenza.org.nz
• For patients www.fightflu.co.nz