No 38/39 - 2020

Influenza vaccination and surveillance of influenza in the 2020/2021 season
Vaccination against pneumococcal disease

Influenza vaccination and surveillance of influenza in the 2020/2021 season

The influenza season runs from Week 40 in the autumn (early October) to Week 20 in the spring (mid-May). As usual, Statens Serum Institut (SSI) monitors the occurrence of influenza in the population throughout the season. However, in the upcoming season, surveillance will be affected by the novel coronavirus (SARS-CoV-2) and by the coronavirus disease (COVID-19), partly due to the overlap of influenza and COVID-19 symptoms, and partly due to the changed routines for sampling for COVID-19, influenza and respiratory infections. See below for further information about surveillance.

As in previous seasons, free vaccination is offered in the 2020/2021 season to special groups at risk of developing severe and complicated influenza illness. These groups include people who have turned 65 years old before 15 January 2021, pregnant women and chronically ill people. As a novelty, influenza vaccination is now offered free of charge to all employees in the healthcare and nursing sectors (for a more detailed description of the offer, please see below).
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Influenza vaccination not only reduces the risk of infection with influenza; it also reduces the risk of developing serious disease, risk of admission to hospital and risk of death due to influenza if you happen to fall ill even if you have been vaccinated.

In the 2019/2020 season, the vaccine coverage among elderly ≥65 years was only 52%, EPI-NEWS 26/20, which was in line with the coverage recorded in the 2018/2019 season, EPI-NEWS 22-23/19. Thus, the coverage still lags far behind the 75% coverage target, recommended by the WHO, which is also the vaccination target in Denmark. Therefore, a greater than effort than usual is being made this year to increase the proportion of vaccinated people.

In the period from week 37 to 39, SSI has sent out a reminder letter to all citizens aged 65 years and above about the free influenza vaccination and the recently introduced free pneumococcal vaccination (see a separate section on this in this issue of EPI-NEWS).

Free influenza vaccination offer starts on 1 October 2020

This year, the free influenza vaccination is offered in the period from 1 October 2020 to 15 January 2021. However, for pregnant women in their 2nd or 3rd trimester and for immunosuppressed persons and their household contacts, the vaccination offer is extended until the end of February 2021.

Influenza vaccines in the 2020/2021 season

This year, three different influenza vaccines are used. Two of the vaccines are the same 4-valent vaccines, Influvac Tetra® and Vaxigrip®, that were also offered in the 2019/2020 season. 

Additionally, a third influenza vaccine will be used, Fluzone®, which is a 3-valent high-dose influenza vaccine with an antibody content above normal for the influenza vaccines (60 μg per virus antigen in the high-dose vaccine and 15 μg in the standard influenza vaccines). This high-dose vaccine provides a higher level of protective antibodies in elderly persons, who generally have a weaker immune system than younger individuals and who therefore respond poorer to the standard vaccine (i.e. achieve a lower level of protective antibodies, and in whom the antibody level drops more rapidly). In this season, the vaccine will be offered to all elderly persons aged 85 years and above.

The composition of the vaccines is based on the WHO's recommendations. The vaccines contain surface proteins from the seasonal influenza viruses that are in circulation globally. The 4-valent vaccines contain two influenza A viruses (H3N2 and H1N1) and two influenza B viruses (B/Yamagata and B/Victoria), whereas the 3-valent high-dose vaccine contains two influenza A virus types (H3N2 and H1N1) and one influenza B virus type (B/Victoria).

None of the 4-valent vaccines contain thiomersal or an adjuvant, but may contain trace amounts of egg/chicken protein, formaldehyde, neomycin and gentamicin. The 3-valent vaccine may contain trace amounts of egg/chicken protein or formaldehyde, but does not contain neomycin or gentamicin. Therefore, persons ≥65 years of age who are allergic to gentamicin or neomycin may be offered the Fluzone® vaccine instead. Unfortunately, this year it has not been possible to secure supply of the inactivated cell-based vaccine which was available for persons with egg allergy in the previous season. Of note, the influenza vaccines may be given in conjunction with the pneumococcal vaccine offered free of charge for all persons aged 65 years or more and to some other high-risk groups in this season. The 4-valent standard vaccines (InfluvacTetra® and VaxigripTetra®) will be available as from week 39/40, whereas the 3-valent high-dose vaccine (Fluzone®) will be available for supply in week 40/41.

Who is comprised by the free influenza vaccination offer?

In pursuance of Executive Order of 10 September 2020 on free influenza vaccination to some population groups, the following persons are entitled to free influenza vaccination:

  • Persons who are 65 years old on 15 January 2021
  • Early retirement pensioners
  • Chronically ill persons who suffer from the following conditions, upon medical assessment:
    o Chronic pulmonary conditions
    o Cardiovascular diseases (barring high blood pressure)
    o Diabetes 1 or 2
    o Congenital or acquired immunodeficiency
    o Patients whose respiration is affected due to muscular weakness
    o Chronic liver or kidney failure
    o Persons with other chronic diseases which, according to the physician’s assessment, pose a serious health risk in conjunction with influenza.
  • Persons with other serious diseases that, according to the doctor’s assessment, pose a serious health risk in conjunction with influenza
  • Severely obese people (recommended BMI > 40), upon medical assessment.
  • All pregnant women in their 2nd or 3rd trimester
  • Household contacts to patients with congenital or acquired immune deficiency may, upon medical assessment, be offered vaccination. Household contacts are members of the household and persons with close contact comparable to that of household members.
  • Staff in the healthcare and nursing sectors tasked with nursing, care and treatment of citizens who are at special risk of running a serious influenza course, including:
    o Doctors
    o Nurses/Pharmacists
    o Chiropractors
    o Dentists
    o Relaxation therapists
    o Surgical appliance makers (orthoists)
    o Bioanalysts
    o Ergotherapists
    o Physiotherapists
    o Midwives
    o Clinical dietitians
    o Optometrists
    o Radiographer
    o Audiology assistants
    o Pharmaconomists
    o Chiropodists
    o Neurophysiology assistants
    o Dental assistants
    o Dental hygienists
    o Dental technicians
    o Employment counselors
    o Carers
    o Nursing-home assistants
    o Social and healthcare assistants
    o Social and healthcare aids
    o Psychologists
    o Medical secretaries
    o Health service secretaries
    o Orderlies
    o Paramedics
    o Ambulance therapists
    o Ambulance drivers

Specifically about influenza vaccination for children

The InfluvacTetra® vaccine may be used for vaccination of children as from three years of age, whereas the VaxigripTetra® is approved for use in children as from six months of age.

Children aged from 6 months through 8 years who have not previously been vaccinated against influenza should receive two vaccinations at a minimum interval of 4 weeks. The same dose is used in children as in adults.

It may be relevant to vaccinate household contacts and other persons close contact with children belonging to the risk groups, including children below 6 months of age who cannot be vaccinated.

Pregnancy and breast-feeding

Pregnant women are at increased risk of suffering serious complications from influenza infection compared with non-pregnant women, and this is particularly evident for influenza A (H1N1) pdm09, which has been in circulation since 2009. The Danish Health Authority therefore recommends influenza vaccination for all pregnant women in their 2nd or 3rd trimester. Pregnant women in their 1st trimester should also be offered vaccination if they belong to a risk group.

Many years of experience with vaccination of pregnant women globally have shown that influenza vaccination during pregnancy is safe for the mother and her child. Influenza vaccination of pregnant women also protects the child in the first months of life as antibodies are transferred from mother to child. The influenza vaccine may also be given during the breastfeeding period.

Degree of protection

Immunity acquired by vaccination with inactivated influenza virus is generally effective from 2-3 weeks after vaccination, and the effect generally lasts 6-12 months. The degree of protection depends mainly on the correlation between the type of virus in circulation and the virus strains in the vaccine. In younger healthy persons, vaccination on average prevents approx. 60% of influenza cases. In the elderly, protection against normal influenza is somewhat lower, but even so, influenza vaccination is the best protection available against serious complications, hospital admission and death.

Adverse reactions and contraindications

Fever, malaise, rigours and tiredness are common vaccination reactions. They typically recede after 1-2 days. The inactivated influenza vaccines cannot cause influenza disease, but the side effects of the vaccine are often misinterpreted by citizens as influenza disease.

Allergy to formaldehyde will most frequently manifest itself as contact dermatitis in which case patch tests may be positive. However, this does not constitute a contraindication. To avoid such reaction, the vaccine may be administered intramuscularly.

Neuraminidase inhibitors can be used for treatment and in some cases also for prevention following specific exposure in persons who cannot be vaccinated due to contraindications.

Registration of vaccinations

All influenza vaccinations shall be registered in the Danish Vaccination Register (DVR) in accordance with Executive Order on Access to and Registration etc. of Medicinal Product and Vaccination Information. If the vaccination information is not automatically reported to the DVR via integration with the electronic patient record used, vaccinations can be registered at www.fmk-online.dk.

Influenza surveillance

As usual, SSI’s influenza surveillance system will operate from week 40. Data from the influenza surveillance will be updated on the SSI website weekly, and news will be published as the influenza situation changes.

The influenza monitoring system is, among others, based on the number of positive laboratory samples, the number of enquiries made by citizens to on-call doctors and to a group of GPs (sentinel doctors) about influenza-like disease. Furthermore, the number of patients admitted to hospital with influenza is monitored, including patients admitted to intensive care units with serious influenza disease, and the number of influenza-related deaths.

However, in the upcoming season, surveillance will expectedly be affected to some extent by the novel coronavirus (SARS-CoV-2) and by the coronavirus disease (COVID-19), partly due to the overlap of influenza and COVID-19 symptoms, partly due to the changed routines for sampling for COVID-19, influenza and other airway conditions, which are currently not undertaken by GPs but by the regional and national COVID-19 test centres.

Information campaigns about free vaccines for special risk groups

This autumn, the Danish Health Authority will draw attention to three different offers of free vaccination for special risk groups. The three offers are: influenza vaccination, pneumococcal vaccination and whooping cough vaccination. For pregnant women, in particular, the campaign includes information about influenza as well as whooping cough vaccination. The campaign on pneumococcal vaccination is described later in this issue of EPI-NEWS.

Influenza vaccination campaign targeting at-risk persons

In connection with the offer of free influenza vaccination for special risk groups, the Danish Health Authority initiates a campaign to inform the target groups of the offer. Additional emphasis is placed on ensuring that at-risk persons are vaccinated against influenza in this season because influenza constitutes a special risk for many of the persons who also risk running a serious course if they become infected with COVID-19. Concurrent infection with both conditions may possibly aggravate the disease course additionally.

You will find more information about the vaccination offer and the campaign at the website of the Danish Health Authority www.sst.dk/influenza. There, you may also download patient information leaflets and video clips for info screens, etc. Two posters and 20 leaflets will be sent to general practices, and extra materials can be ordered at the website of the Danish Health Authority. In addition to Danish language, the materials will be available in 11 other languages.

Influenza vaccination campaign targeting healthcare and nursing staff with patient contact

Healthcare and nursing staff on a daily basis see patients and citizens who are at special risk of running a serious course of both influenza and COVID-19, and the influenza vaccination offer was designed to protect the individual staff member from influenza and also to protect the citizens and patients who are at special risk of becoming infected with influenza by the staff member. We expect that healthcare and nursing staff may receive vaccination at their place of work. Materials informing of the campaign have been developed and may be ordered at www.sst.dk/influenza.

Information campaign targeting pregnant women about influenza and whooping cough vaccination

A study conducted for the Danish Health Authority has shown that many pregnant women are unaware of the offer of free influenza vaccination. Therefore, the Danish Health Authority will initiate an information campaign also comprising whooping cough. The campaign will primarily run on social media and in apps targeting pregnant women. This campaign will also include posters and “business cards”, which will be sent to GPs when they order vaccines. For more information about the offer, please see www.sst.dk/gravid-vaccination. The above page also allows you to download various materials which - in line with the other campaigns - will also be available in 11 other languages.

(L.S. Vestergaard, L.K. Knudsen, T.G. Krause, Department of infectious Disease Epidemiology and Prevention, N. Svejborg, B. Søborg, Unit for Evidence, Education and Emergency Services, Danish Health Authority)

Vaccination against pneumococcal disease

As described above, this year a letter was sent to all citizens aged 65 years or more about the offer of influenza and pneumococcal vaccination free of charge. The objective of offering pneumococcal vaccination is to reduce the occurrence of pneumonia caused by pneumococci and invasive pneumococcal disease among elderly citizens and persons who are at increased risk if they become infected with pneumococcal disease, EPI-NEWS 14-16/20, 17/20 and 23/20. During the COVID-19 epidemic, this will also reduce the risk of double infections and contribute to reducing the workload at hospitals. The vaccine given is the PPV23 (Pneumovax®), which provides protection against 23 different pneumococcal types. PPV23 prevents pneumonia, meningitis and blood poisoning caused by the pneumococcal types contained in the vaccine. The pneumococcal vaccine may be given at the same session and therefore concomitantly with the influenza vaccine, but at separate injection sites.

Free PPV23 vaccination should be offered only to person groups who have not received PPV23 vaccination within the past six years. This is ensured by look-up in the Danish Vaccination Register, by asking the patient or by checking the vaccination card. In case of doubt, please confer with the patient’s GP if someone else is handling the vaccination. If it is assessed that revaccination with PPV23 is needed before six years have passed since the previous PPV23 vaccination, this should be done following measurement of pneumococcal antibodies (guidance:https://www.retsinformation.dk/eli/retsinfo/2020/9334)

Vaccination may be performed by a doctor authorised to practice medicine in Denmark or it may be delegated by such doctor. For further information, please see the website of the Danish Medical Association.  

As previously, in persons affected by conditions or diseases that may increase the risk of invasive pneumococcal disease, a combined vaccination schedule may be followed by giving a 13-valent conjugated vaccine (PCV13) and PPV23. The PCV13 is not comprised by the free programme, but a subsidy is available for some groups.

The Danish Health Authority’s information campaign on pneumococcal vaccination

As per 15 June 2020, all persons aged 65 years or more and children affected by some chronic conditions and other citizens at special risk have been offered pneumococcal vaccination free of charge with the 23-valent Pneumovax® vaccine.

Many of the persons who are at risk of running a serious disease course if they become infected with pneumococci are also at special risk if infected with COVID-19. Therefore, these persons are now offered pneumococcal vaccination free of charge.

The Danish Health Authority launches an information campaign targeting the relevant groups in connection with the vaccination offer. The information campaign consists of posters, leaflets, video clips, banners and other graphic elements. Two posters and 20 leaflets will be sent to GPs at the time vaccines may be ordered. The remaining materials may be downloaded from the website of the Danish Health Authority www.sst.dk/pv. The poster and folder will be translated into 11 languages along with the remaining information material.

(L. Hallundbæk, P. Valentiner-Branth, Department of infectious Disease Epidemiology and Prevention, N. Svejborg, B. Søborg, Unit for Evidence, Education and Emergency Services, Danish Health Authority)