Influenza vaccination – still a priority

The seasonal flu campaign remains a critically important public health intervention to reduce morbidity, mortality and hospitalisation associated with flu within the struggling NHS (Gov.UK, 2023a). This is a certainly a challenging time working in NHS and social care which is still recovering from the impact of the coronavirus (COVID-19) pandemic. Certainly, last winter we saw a surge in respiratory illness and an increase death rate associated to influenzae and pneumonia (Iacobucci, 2023). There is therefore a high value associated to the influenzae vaccination campaign with an aim is to offer vaccination to as many eligible people as possible (Gov.UK, 2023). It is therefore important to identify who is eligible for vaccination and to be aware of the different vaccinations (see Table 1). This is also a potential to be a challenging time as the social contact increases as the use for social distancing and use of PPE decreases. There are also concerns that there is re-emergence of infectious diseases alongside influenzae due to the decreased access to health and medical services (Kenarkoohi et al, 2023).

There is therefore an extensive list of those who are eligible for their influenzae vaccination (see Table 2). General practices should continue to invite eligible school aged children in clinical risk groups for flu vaccination to ensure that they can access a vaccine before flu starts to circulate but they will also be offered immunisation by the school age immunisation service. There is also a change to secondary school-aged children in years 7–11 in school of home educated which was included to in the amended annual flu vaccination letter.

Causative organism

Influenzae is caused by a member of the RNA viruses of the family Orthomyxoviridae family of which there are four types of seasonal influenza viruses: types A, B, C and D (Gov. UK, 2023). They are classified into subtypes according to the proteins on the surface of the virus such as hemagglutinin (HA) and the neuraminidase (NA). Influenza A viruses are the more significant of the types of flu and can lead to pandemics. The current influenzae A types circulating in the general population are A (H1N1) and A (H3N2) influenza viruses. This can change, however, as surface antigens from influenza A make these viruses antigenically labile and the minor changes which can occur are called antigenic drift which occur progressively from season to season, meaning that the flu vaccination must change year-on-year, (Duncan, 2015). The influenza vaccine is therefore most effective when the vaccines are specifically designed to target the circulating viruses (WHO, 2023). The World Health Organisation (WHO) Global Influenza Surveillance and Response System (GISRS) continuously monitors the influenza viruses circulating in the population and recommend to the oint Committee on Vaccination and Immunisation (JCVI) the composition of the influenza vaccines twice a year (WHO, 2023). Influenza activity is monitored in the UK through sentinel GP practices, virological surveillance and weekly reports from PHE, Health Protection Scotland, Public Health Wales, and the Public Health Agency in Northern Ireland. This information is forwarded to the JCVI.

The WHO therefore recommends that quadrivalent vaccines for use in the 2023–2024 which are egg-based vaccines should contain the following:

• A/Victoria/4897/2022 (H1N1) pdm09-like virus A/Darwin/9/2021 (H3N2)-like virus
• B/Austria/1359417/2021 (B/Victoria lineage)-like virus a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

Cell culture- or recombinant-based vaccines should contain: A/Wisconsin/67/2022 (H1N1) pdm09-like virus rather than the A/Victoria/4897/2022 (H1N1) pdm09-like virus.

The WHO recommends that trivalent vaccines which egg-based vaccines do not include a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus

Transmission

Influenza is highly infectious with an incubation period of 1–3 days, enabling it to spread quickly in crowded areas including schools and nurseries, (WHO, 2023). It is transmitted by droplets, aerosol or through direct contact with infected secretions and cannot survive long on skins but can survive longer on hard surfaces, (Killingley and Nguyen-Van-Tam 2013).

Symptoms

The symptoms of influenza are an unusual sudden onset of a high fever, dry cough, headache, myalgia, severe malaise, sore throat, and a runny nose, (Duncan, 2015; WHO, 2023). Generally, this can be an unpleasant but a self-limiting disease with recovery usually within 2–7 days within 50–70% of patients. (WHO, 2023)

The risk of serious illness from influenza is higher amongst children under 6 months of age (Zhang et al, 2012). Gill et al (2015) suggest that children at risk of hospital admission with influenzae are those with a history of neurological disorders, prematurity, sickle cell disease, diabetes and age younger than 2 years. Those who are immunosuppressed are also at risk of hospitalisation or complications of influenzae. In pregnancy, women are immunocompromised, and this is complicated by a reduced lung capacity and anaemia, (Duncan, 2020). Influenza during pregnancy may also be associated with perinatal mortality, prematurity, smaller neonatal size, and lower birth weight and admission to intensive care, (Sappenfield et al, 2013).

Complications

The most common complications of influenza in adults according to the WHO (2023) are:

• Acute bronchitis
• Pneumonia
• Exacerbations of asthma or other respiratory conditions
• Otitis media
• Sinusitis

Other complications such as bronchitis, secondary bacterial pneumonia or otitis media particularly in children, can occur, (WHO, 2023). A reminder perhaps that the pneumonia vaccination can be given concurrently for those in the at-risk groups. Other more serious complications are meningitis, encephalitis or meningoencephalitis. The risk of these complications is higher amongst children under six months of age, Zhang et al, 2012. The types of complication can also differ dependent on the circulating influenzae strain. Seasons which are dominated by the H3N2 viruses are associated with a higher death rate hospitalization, compared with those caused by influenza A (H1N1) or influenza B viruses. This can cause bacterial pneumonia with associated methicillin-resistant Staphylococcus aureus (MRSA), and encephalitis, (Podewils et al, 2005).

Prevention

Prevention, and particularly immunisation, are key aspects of the Department of Health's (DoH) management of influenzae, (Gov.UK, 2023). This is a key role of the General practice nurse, (GPN) advocating for the immunisation strategy. Certainly, these are challenging times trying to keep up to date on the recommendations for influenza, and addressing barriers to implementing practices that increase vaccination rates, (Hunter et al, 2020). GPNS play a significant role in overcoming patient fears and maintaining high coverage rates in practice (Petousis-Harris et al, 2005).

The national flu immunisation programme aims to protect those who are at high risk of flu-associated morbidity and mortality, and each vaccine includes protection against influenza A (H1N1) and A (H3N2), and one or two influenza B viruses, (Gov.UK, 2023).

Pregnancy

Since 2012, the flu vaccine is recommended as the main aspect of prevention for pregnant women worldwide, (WHO, 2023). Pregnant women are recommended for seasonal influenza vaccinations and identified as a priority group for vaccination. The vaccination not only protects the mother but also the foetus, (Arora & Lakshmi, 2021). Data on influenza vaccine safety in pregnancy is considered inadequate by some researchers but there are a few studies that report no serious side-effects in women or their infants, including no indication of harm from vaccination in the first trimester, (Aora & Lakshmi, 2021: Mak et al, 2008). Ultimately it is suggested that the benefits outweigh any risks due to the vaccine, (Duncan, 2020). The attenuated live influenza vaccine is contraindicated in pregnancy, so the inactivated vaccine is recommended. (Gov.UK, 2023)

Children

Each year 900,000 children under 5 years of age globally are thought to be hospitalised due to influenzae, (WHO, 2023). The rate of influenza is approximately 5–10% in adults, but it is 20–30% among children (Orrico-Sánchez et al, 2023). Young children, especially those in nursery or school, are thought to be the main vectors of the spread of the influenza virus with their local communities, (Orrico-Sánchez et al, 2023). Children are also ‘super-spreaders’ of the virus as they shed larger amounts of virus and for a longer period.

Despite the national recommendations for flu vaccination for children not all children receive the vaccination. Some children have a history of sporadic vaccinations. Fogel & Hicks, (2020) suggest that the parents of these flu-floppers who only provided a reason for nonattendance in 43% of cases. The barriers to vaccination have been shown to include a combination of factors such as lack of convenient access and the flu vaccination being a low priority for busy parents, (Price et al, 2022). Smith et al (2017) suggest that the factors associated with poor uptake of flu vaccination for children in 2017 campaign where due to the belief that the vaccine is unsafe and the potential of short-term side-effects or long-term health problems. However, Bachtiger et al (2021) found that post COVID-19 there has been an increased acceptance of the influenza vaccination in previous hesitant people. There is a challenge to educate patients or parents who have concerns about vaccine safety or are anxious about inactivating agents, adjuvants, preservatives, or new technologies, (Löffler, 2021).

Certainly, vaccine hesitancy where there is a delay in acceptance or refusal of vaccination has been identified by the WHO as one of the top 10 threats to global health. Despite the rise in vaccination this is something we need to educate the population about to ensure post COVID-19 people are still vaccine aware. This is something that the GPN can do as part of their role-highlighting the importance of vaccination.

We also need to dispel health myths and misinformation that poses severe risks to people's health decisions and outcomes. Many in the population saw the fast-tracked vaccines with COVID-19 and the information in the media about safety and efficacy testing of these vaccines. Löffler, (2021) suggests that the rapid distribution of conspiracy theories had led to vaccine hesitancy. It is helpful to remind parents that the fast-track seasonal influenzae vaccine production has been around for several years. Yap et al (2010) highlight that knowledge has a significant influence on the attitudes and practices relating to immunization. The recommendations are that children aged 6 months to under 2 years in a clinical risk group should be offered QIVc (Cell-based quadrivalent influenza vaccine). If QIVc is not available to be given to the patient then you can administer QIVe, (Gov.UK, 2023). Children aged 2 years to under 18 years in eligible year groups or in a clinical risk group should be offered the quadrivalent LAIV nasal suspension. If LAIV is contraindicated for the patient, then they can be given the call based quadrivalent influenzae vaccine QIVc or QIVe, (Gov.UK, 2023).

The elderly

There is a reduced efficacy of vaccination in the elderly which is thought to be due to due to immunosenescence where there is a lower immunity and protective antibody responses (Dugan et al, 2020). Age-related immunosenescence can lead to a reduced vaccine-induced B cell and T cellmediated adaptive immune response to a vaccine (Choi et al, 2022). Certainly, in the last decade there have been more immunogenic vaccine formulations manufactured for the elderly such as the aQIV vaccine (Marbaix et al, 2023). The aQIV is a vaccination which combines the MF59^® adjuvant emulsion with a standard dose of antigen designed to produce stronger and longer immune response, (Fochesato et al, 2022; Marbaix et al, 2023). This has been successful in reducing the number of influenzae related hospitalisations in the elderly, (Marbaix et al, 2023). Choi et al (2022) showed that switching vaccines from QIV to aQIV significantly reduces the influenza-associated disease burden of the elderly population. Enhanced vaccines such as aQIV and HD-QIV therefore provide better protection than standard-dose QIV for the elderly (Choi et al, 2022; Marbaix et al, 2023).

The at-risk groups

The uptake of the flu vaccination in the at-risk groups can flocculate from country to country (Loerbroks, et al, 2012). Ciblak & Platformu's (2013) survey of patients in this group in Turkey found that the that leading factor negatively influencing vaccine uptake was disbelief in the effectiveness of vaccine. Rates of vaccine uptake in the UK have been lower that the WHO recommendations and other countries in Europe, (Oakley et al, 2021). Vaccination in high-risk individuals has remained at around 50% since 2008/9 despite higher morbidity and mortality in these groups, (Cromer et al, 2014; Oakley et al, 2021). Perhaps we can use the strategies developed for COVID-19 vaccinations such as developing local approaches by utilising the local community to co-producing communications and materials that meet the populations health literacy needs (Razai et al, 2021).

Summary

As we head into the flu 2023's season in the Northern Hemisphere, we are aware that this will lead to many challenges for our already stretched health care services. The strategy for the prevention of influenzae has been for a long time one of vaccination and education, (Duncan, 2015). The hope is that the 2022–2023 seasonal influenzae vaccination increase in vaccine uptake will continue into this new season. The general practice nurse still has a significant role in reducing vaccine hesitancy and dispelling the myths and disbeliefs associated with vaccinations.