No 39a - 2012

Free influenza vaccination

In accordance with Executive Order of 26 June 2012 on free influenza vaccination to selected population groups, the following persons residing in Denmark are entitled to free influenza vaccination:

• Persons who at the time of the vaccination have reached the age of 65 years 
• Early retirement pensioners 
• Chronically ill persons who suffer from the following conditions, upon medical assessment:
  - chronic pulmonary conditions
  - cardiovascular diseases (barring high blood pressure with no concurrent conditions)
  - diabetes 1 or 2
  - congenital or acquired immunodeficiency
  - patients whose respiration is affected due to muscular weakness
  - chronic liver or kidney failure
  - other chronic diseases which, according to the physician’s assessment, pose a serious health risk in conjunction with influenza
• Severely obese persons (recommended BMI > 40) 
• Persons with other serious diseases which, according to the doctor’s assessment, pose a serious health risk in conjunction with influenza. 
• Pregnant women in their 2nd or 3rd trimester 
• Household contacts of severely immunosuppressed patients.

The Danish Health and Medicines Authority has prepared a guideline on free influenza vaccination to accompany the Executive Order. The guideline is available (in Danish language) at www.sst.dk.

The offer of free vaccination is valid as from 1 October until the end of 2012. For pregnant women in their 2nd or 3rd trimester, the offer remains valid until 1 March 2013.

Information

As in previous years, the Danish Health and Medicines Authority will run a campaign to inform of influenza vaccination.

In weeks 37 and 38, posters and other material were sent to GPs municipalities, pharmacies and midwife centres. Extra posters and visiting cards on influenza vaccination may be ordered at the Danish Health and Medicines Authority on phone: 70 26 26 36.

Furthermore, information letters targeting patients at risk and the remaining materials are available for download (in Danish language) at the following webpage: www.beskytdigmodinfluenza.dk. Additionally, the campaign consists of TV spots, which will run in weeks 39 and 40, and adds in periodicals, newspapers and patient association publications.

Children

Children above the age of six months with a risk of running a serious influenza course should be vaccinated. In the majority of cases, such children are monitored by a paediatric clinic, but they may also receive free vaccination at a specialist or at a vaccination clinic. A guideline from the Danish Paediatric Society is available for download (in Danish) at www.paediatri.dk.

Children aged from six months to eight years, who have not previously been vaccinated against influenza, should receive two vaccinations at a minimum interval of four weeks. Children aged six to 35 months are vaccinated using only half the vaccine dose.

It may be relevant to vaccinate household contacts and other persons who come into close contact with children belonging to the risk groups.

Pregnancy and breast-feeding

Influenza vaccination is recommended for all pregnant women in their 2nd or 3rd trimesters. Pregnant women in their first trimester of pregnancy are also vaccinated provided they belong to a risk group.

Experience with vaccination of pregnant women has demonstrated that there is no increased risk of congenital abnormalities or other pregnancy-associated secondary effects. Influenza vaccines may be given during the period of breastfeeding.

Disseminated sclerosis and HIV

Patients with disseminated sclerosis may risk having new attacks if complicated by influenza. The risk of new attacks as a result of vaccination has not been observed. Guidance concerning vaccination of HIV-infected patients is available from the infectious diseases department where the patient attends follow-up.

Influenza vaccines in the 2012/2013 season

The vaccines contain the primary strains of the three seasonal influenza viruses currently in global circulation:

• A/California/7/2009 (H1N1)-like virus (2009 pandemic virus)
• A/Victoria/361/2011 (H3N2)-like virus
• B/Wisconsin/1/2010-like virus

The vaccines comply with the WHO recommendation for the Northern Hemisphere for the 2012/2013 season. Influenza vaccines from the previous season should not be used due to limited in-use storage time.

Delivery

In 2012, a total of four vaccines were ordered from four manufacturers. None of the vaccines contain adjuvant or thiomersal. Three of the vaccines contain components of inactivated influenza virus (split vaccine). These are distributed as first-choice to children and adults and are regarded as equal with regard to protection against influenza. This year it is also possible to order a vaccine containing live attenuated influenza virus, which is administered intranasally to children aged 2-17 years. This latter vaccine is more expensive than those previously mentioned. For more detailed information on the individual products and "Questions & Answers", please see. www.ssi.dk.

Degree of protection

Immunity achieved through vaccination with inactivated influenza virus is generally effective 2-3 weeks after vaccination, and the effect typically lasts 6-12 months. The degree of protection is, in particular, dependent on the correlation between the type of virus in circulation and the virus strains in the vaccine.

In young, healthy persons, vaccination prevents 70-90% of influenza cases. In elderly persons, protection against ordinary influenza illness is somewhat lower. Protection against serious complications, hospital admissions and death in the elderly is up to 60%.

Adverse reactions and contraindications

Fever, malaise, rigours and tiredness are common reactions which typically recede after 1-2 days. The inactivated influenza vaccines do not cause influenza illness.

Persons who are hypersensitive to chicken eggs/chicken protein or other vaccine ingredients and who previously experienced an anaphylactic reaction should not be vaccinated. Allergy to formaldehyde will most frequently manifest itself as contact dermatitis in connection with which patch tests may be positive; this does not comprise a contraindication. To avoid such reaction, the vaccine may be administered intramuscularly. Neuraminidase inhibitors may be used prophylactically in persons who are unvaccinated due to contraindications and in any unvaccinated contact persons.

(T.G. Krause, L.K. Knudsen, Department of infectious Disease Epidemiology)


26 September 2012