No 37 - 2015

Frequently asked questions about vaccination
Cluster of ornithosis cases following contact to infected ducks from duck breeders on Funen and in Jutland

Frequently asked questions about vaccination

The Department of Infectious Disease Epidemiology at Statens Serum Institut offers advice over the phone for healthcare workers. The service is open daily from 8.30 to 11.00 and from 14.00 to 15.00 on phone: +45 3268 3037. Occasionally, waiting times may be rather long and we therefore kindly draw your attention to our written advice service, which answers e-mail enquiries received at

Furthermore, we recommend that you consult our website where you may find the answers to a wide range of questions. Among others you will find an updated list of the EPI-NEWS issues used most frequently when providing advice (in Danish).

Furthermore, based on experience from our daily advisory service, we have prepared this issue of EPI-NEWS, which contains answers to the most frequently asked questions on vaccination, including a range of useful links.

Do you need to re-initiate a vaccination series when the interval between vaccines exceeds the recommended interval?
No, in persons with a normal immune response, you should never re-initiate a vaccination series. You simply proceed by giving the next dose in the series.

Example: A person received the initial Engerix-B vaccination 10 years ago and would now like to conclude the vaccination series. You give the second and the third Engerix-B vaccinations at a 5-month interval, as you normally would. The duration of protection will be equivalent to that achieved if the vaccinations had been given at the recommended intervals, but the person has not been protected in the period that passed between the first and second vaccination.

Can you shorten the interval between the vaccinations of a series if it would otherwise not be possible to give the recommended vaccinations before protection is required?
No, it is important to observe the minimum intervals between the vaccinations of a vaccination series, as you cannot otherwise be sure to achieve sufficient protection.

Example: The first dose of Havrix was given on 1 June. The second dose of Havrix was given on 1 October. As the second dose was given at an interval shorter than the recommended one (6 months), an extra dose is given at the correct interval calculated from the latest vaccination administered - i.e. no earlier than by 1 April.

For Japanese encephalitis, hepatitis B and hepatitis A+B combination vaccine for adults, you may employ an accelerated regime (cf. the summary of product characteristics).

The child was fidgety during the vaccination and I therefore failed to inject the full syringe contents - What should I do?
If the full vaccine contents were not injected, you need to supplement with an amount corresponding to what was not given or administer a full vaccination without delay to ensure sufficient protection.

I have just administered a 5-month vaccination, but forgot to mix in the powder - What should I do?
If you forget to mix in the powder (the Hib component) when preparing the DTaP-IPV syringe, the Hip powder may be suspended in 0.5 ml of saline and then be injected intramuscularly, EPI-NEWS 27-33/15. If the Hib component has been discarded, you may order Hib vaccine separately.

For how long are you protected after having received the hepatitis A and B vaccination series?
The duration of protection once you have concluded a vaccination series against hepatitis A is a minimum of 30 years, and protection against hepatitis B is life-long, provided the patient's immune response is normal.

May a person who has received Havrix as the first dose against hepatitis A be given Vaqta, Avaxim or Epaxal in the second dose?
We recommend that you conclude the series using the same medicinal product, but if the product has been discontinued or is not currently available, you may give another inactivated hepatitis A vaccine and the patient will achieve the same duration of protection.

Are there any limits to how many vaccines may be given concurrently?
No, the body's immune response can easily handle several concurrent vaccines. Nevertheless, you should never mix several vaccines in a single syringe, unless the packing instructions clearly allow this. You should choose separate injection sites separated by a minimum of 2.5 cm.

Special precautions apply for vaccination against tuberculosis (see the summary of product characteristics, specifically the section on interaction with other medicinal products and other forms of interaction).

My patient is preparing for an exchange stay in the US and I have therefore administered a diphtheria-tetanus booster (diTe-Booster).Now I've discovered that they also have a requirement for whooping cough vaccination in place - Is it possible to purchase a whooping cough-only vaccine?
Whooping cough booster vaccination is often needed prior to exchange stays in the US. This may be achieved by giving a DTaP booster or a DTaP-IPV booster.

The whooping cough component is not available separately, so if you have already given a diphtheria-tetanus-containing vaccination without the whooping cough component, one of the above-stated combinations is needed subsequently. You should then inform the patient that there is an increased risk of exaggerated local reaction including soreness, erythema and swelling. If it is not possible to provide the extra vaccine within few days, it is better to wait as long as possible and give the vaccine closer to the departure date.

Can boys be vaccinated against HPV?
Yes; and the same guidelines apply to boys and girls, apart from the fact that boys are required to defray the costs of the vaccination themselves.

May a child who is running a fever be vaccinated?
In case of acute illness with a high fever, vaccination should be postponed. Mild infections such as an ordinary cold with or without fever should not postpone vaccination. Children who are possibly developing illness or who are undergoing work-up should not receive vaccination before their condition is stable and has been diagnosed.

Where do I find information about the individual vaccines – for example minimum intervals, contraindications and protective efficacy?
Read about the individual vaccines at under the folder Vaccination -> De enkelte vacciner. (In Danish).

To the right on the screen you may find a link to the Summary of Product Characteristics for the individual vaccine, where more detailed information may be retrieved.

My patient developed an aluminium granuloma following DTaP-IPV vaccination. Should he receive the 5-year booster vaccination?
Development of aluminium granuloma following vaccination with aluminium-containing vaccines (including DTaP-IPV/Act-HIB and Prevenar) is a known and non-severe side-effect, which is transient, even if the discomfort may be prolonged. Granulomas are 3-25 mm in diameter and are frequently accompanied by itching and eczema and in some cases hyperpigmentation and hypertrichosis (increased hair growth). The granuloma is caused by allergy to aluminium, and the discomfort may continue for several years.

Aluminium allergy recedes or disappears over time, and the risk of forming granulomas is lower if subsequent aluminium-containing vaccinations are administered as deep intramuscular injections. Furthermore, it has been demonstrated that 2 in every 3 children in whom aluminium allergy is detected have out-grown their allergy within a 5-year period.

The risk of recurrence shall therefore be weighed against the risk of infection with a potentially life-threatening infection, and we therefore recommend completing the childhood vaccination programme (DTaP-IPV/Act-Hib and Prevenar). Read more about aluminium granulomas in The Journal of the Danish Medical Association (Ugeskrift for Læger), 2014 and in News about Adverse Effects (Nyt Om Bivirkninger), 2013 (Danish Health and Medicines Authority).

Would you refresh my memory with regard to the intervals for inactivated and live attenuated vaccines?
EPI-NEWS 2015 no 37 - figure 1 
Please find a list of recommended intervals and minimum intervals for vaccines here.

How do I adapt a child who has not initiated the Danish childhood vaccination programme?
In EPI-NEWS 5a/15, we present every vaccine component in the Danish childhood vaccination programme explaining how to adapt children to the programme (number of doses, intervals and age at first vaccination, etc.).

In the situation where a child has followed another country's childhood vaccination programme, but where you cannot read the vaccination card, the WHO’s list of the childhood vaccination programmes of the individual countries will be helpful (scroll down a bit on the page, point to the abbreviations on the page to see the full vaccine names).

If a child has missed a DTaP-IPV/Hib primary vaccine, but has received the 5-year booster - is the child then sufficiently covered?
No, three primary vaccinations must have been given prior to the booster in order to ensure long-term protection. In this case, you need to disregard the booster vaccination given and administer the third primary vaccination (no less than 6 months after the booster vaccination) and then repeat the booster vaccination 4 years later. Nevertheless, in persons aged ≥10 years, booster vaccination may replace primary vaccination EPI-NEWS 5a/15.

Where can I read more about the vaccines of the Danish childhood vaccination programme?
At under Questions and answers (in Danish) about the vaccines of the childhood vaccination programme.

Where can I find good knowledge that I may use when providing advice to patients before travels?
You may get an overview of recommended vaccinations prior to travels by entering the type and duration of the travel at Travels and Infectious Diseases (in Danish), and by referring to the latest issue of EPI-NEWS on Recommended vaccinations for foreign travel, EPI-NEWS 26a+b/15 (where you will also find the transmission period for Japanese encephalitis).

Where can one check which vaccinations a child has received?
The Danish Vaccination Register (DVR) gives citizens and healthcare workers alike the opportunity to access a full list of any vaccinations settled with the National Danish Health Insurance (Sygesikringen) since 1996. You can access the electronic vaccination card through, where you will find a separate tab for vaccination information. See

Vaccinations that have been administered, but which have not been registered on the electronic vaccination card can be settled with the relevant Danish Region up to 3 years after the vaccination was given (and will then automatically be recorded in the DVR). If the vaccination was given more than 3 years ago, you need to register the vaccination manually FMK-online.

Advice is not given to private citizens
The Department of Infectious Disease Epidemiology receives numerous enquiries from private citizens. We would like to take this opportunity to mention that we provide advice only for healthcare workers, and physicians therefore cannot refer their patients for our advisory services. "The Travel Vaccination Clinic" (Udlandsvaccinationen in Danish language) is a private vaccination clinic, which is housed at the same address as Statens Serum Institut, but has no association with the Department of Infectious Disease Epidemiology or with other parts of the SSI.
(S. Voss on behalf of the Consultancy Team, Department of Infectious Disease Epidemiology)

Cluster of ornithosis cases following contact to infected ducks from duck breeders on Funen and in Jutland

Ornithosis is caused by the Chlamydophila psittaci bacterium, which is excreted through the droppings and nasal secretion from infected birds from where it may be transferred to humans. The bacterium is resistant to some dehydration, and transfer to humans most frequently occurs via inhalation of atomised faeces or secretion, but also by mouth-to-beak contact or via contact with the plumage and tissue of infected birds.

Infection was observed due to transportation of ducklings in the driver's cab of cars or after providing assistance during capture or release, e.g. for hunting purposes. Person-to-person transfer is rare, if at all possible. The diagnosis can be made early in the course of the disease through detection of C. psittaci in lower airway secretion by PCR. Furthermore, antibodies can be detected in blood samples, but it takes 2-3 weeks or more for the analyses to test positive. In Denmark, C. psittaci is not cultured routinely in human specimens. Ornithosis (mainly in connection with pneumonia) can be treated with antibiotics.

Ornithosis is notifiable to the Department of Infectious Disease Epidemiology at Statens Serum Institut (SSI) and to the Medical Officers of Health on Form 1515 in case of clinical diagnosis with epidemiological support and/or in case of microbiological verification.

EPI-NEWS 2015 no 37 - table 1

The 2011-2014 period witnessed an increasing number of human ornithosis cases infected in Denmark, and already at this point in 2015 the SSI has recorded a number, which - if the trend is sustained - will result in a total increase of approx. 100% compared with 2014, Table 1.

Cluster of cases

The investigation of the reason for the relatively high number of cases observed to date in 2015 has revealed a cluster of cases following contact to ducks from breeders on Funen and in Jutland in the period from May to August 2015. One person fell ill after buying ducks from a duck breeder on Funen in late May. Next, another 5 persons fell ill in the course of June, July and August following either purchase from or employment with another duck breeder on Funen. Two persons with possible contact to a breeder from Jutland of various types of birds, including pigeons and ducks, fell ill in June and July, respectively. One of these persons brought ducks from the breeder in Jutland to the person’s own farm where a number of hens were already being kept.


The Medical Officers of Health informed the Danish Veterinary and Food Administration (DVFA), which implemented measures relating to the breeders. The DVFA tracked traded birds from the infected breeders to determine if any birds were still held captive and informed the owners that in case of influenza-like symptoms or difficulty breathing, they should see a doctor stating that they had come into contact with ducks/pigeons or parrots infected with ornithosis. Subsequently, the infection was confirmed and the ducks were either treated or destroyed.


Ornithosis primarily affects parrots, pigeons and ducks. Not all infected birds present with clinical symptoms. A shared characteristic of the two outbreaks among ducklings on Funen is that contact to pigeons was also seen. Generally, there is no association between serotype and host bird species. Thus, infection can be transferred between various species of bird, e.g. from pigeons to ducks.

The signs of infection include discharge (secretion) from the eyes and nose, diarrhoea and low body weight. Sick birds and birds that have not come into contact with sick birds shall be isolated and treated, and may not be traded or passed on. Animal traders, bird breeders, bird parks and the like have an obligation to keep records of all birds they trade or pass on.

These records are used by the Danish Veterinary and Food Administration for infection tracking. On suspicion of ornithosis (chlamydiosis), the bird or poultry keeper shall immediately call a veterinarian, in pursuance of Executive Order on Ornithosis (in Danish).
(C. Kjelsø, Department of Infectious Disease Epidemiology, S. Uldum, Microbiology and Infection Control, B. Hendriksen, The Danish Veterinary and Food Administration, Division East)

Link to previous issues of EPI-NEWS

9 September 2015