No 20 - 2019

HAIBA 2018
Study of the vaccination coverage for the 5-year booster in Copenhagen

HAIBA 2018

HAIBA (Hospital-Acquired Infections Database) is increasingly used in infection control and clinical practice in the Danish hospital sector. Throughout the year, an inspiring dialogue has evolved between users and Statens Serum Institut. This dialogue has paved the way for new potential uses of the HAIBA. On the theme day held in December 2018, experiences were shared, and participants were encouraged to think creatively about new possible uses for HAIBA. One of the challenges is to present data in a manner that ensures that they are seen as relevant and motivating for doctors and nurses in clinical practice, thereby ensuring that data will be used in the prevention of hospital-acquired infections.

For a detailed description of the use of HAIBA, development plans and a report on occurrence in the 2014-2018 period, please see the 2018 Annual Report on HAIBA.

In 2017, the National Audit Office of Denmark encouraged the Danish Regions to establish regional indicators and objectives for the occurrence of hospital-acquired infections. A pivotal element in this work is to establish which and how many infections are preventable, and which infections should be considered non-preventable complications. We have no simple answer to this question, which makes it difficult to establish useful, realistic indicators and objectives. Even so, these past few years have, indeed, seen the development of indicators, among others the regularly updated key healthcare figures published by Danish Regions that include figures on hospital-acquired bacteraemia and Clostridium difficile infections.

At its annual meeting, the Danish Orthopaedic Surgery Society decided that HAIBA data on postoperative infections following total hip and knee arthroplasty should be included in the annual reports from the Danish Hip Arthroplasty Register and the Danish Knee Arthroplasty Register. In some regions, these indicators have triggered studies aiming to determine if the infection occurrence has increased, or if the region generally has a high infection occurrence. These experiences are essential for the continuing dialogue about useful indicators.

HAIBA must be adapted regularly to reflect the ongoing development of Danish healthcare, where admission periods are constantly being reduced, more outpatient contacts are seen, and more patients receive treatment in their homes. Case definitions have been optimised in 2018 and will take effect in the course of 2019. With these changes, focus is moved towards monitoring of health-sector-acquired infections rather than monitoring of hospital-acquired infections only.

As the conditions in Danish Healthcare are changing, HAIBA’s data sources are also changing. In 2018, considerable efforts were made to prepare HAIBA for the National Patient Register’s new data model (LPR3) and the codes from the National Register of Healthcare Organisations (NRHO) which will be replacing the current Hospital Department Codes . The introduction of LPR3 and NRHO already affects the figures presented in the 2018 annual report on infections or hip and knee arthroplasties performed in November and December, as these figures cannot be monitored throughout the full 90-day follow-up period. The considerable changes in the LPR3 and NRHO will be reflected in HAIBA data for 2019, and this will challenge HAIBA’s past data history.

It has become evident that the methods developed by HAIBA create new opportunities with respect to infection control and preparedness. The HAIBA method used to handle hospital contacts is now also being used in the national influenza surveillance. Additionally, the HAIBA group has developed an indicator for 30-day mortality following bacteraemia, and a co-operation has been initiated to establish national monitoring of all bacteraemias based on HAIBA algorithms.

The growing interest in HAIBA data and the many initiatives and new ideas about possible uses show that HAIBA is a tool capable of underpinning infection control, thereby preventing hospital-acquired infections.

The HAIBA group would like to take this opportunity to express their gratitude towards partners for their efforts in the course of the past year, among others the infection control organisations, the Danish Hip Arthroplasty Register, the Danish Knee Arthroplasty Register, the Danish Society for Clinical Microbiology, the Learning and Quality Team for Rational Use of Antimicrobials, the Danish Regions’ Clinical Quality Development Programme and the Capital Region of Denmark’s Task Force for Reducing Hospital-acquired Infections.

(S. Gubbels, M. Chaine, I. Irshad, M. Kristiansen, K.S. Nielsen, M. Voldstedlund, Data Integration & Analysis, J. Holt, C.S. Jensen, B. Kristensen, J. Nielsen, Department of Infectious Disease Epidemiology and Prevention, K. Mølbak, Infection Preparedness, M. Haahr, Customer Relations and Application Management, Danish Health Data Authority, A.M.B. Hellesøe, The Capital Region of Denmark’s Task Force for Reducing Hospital-acquired Infections, Copenhagen University Hospital (Rigshospitalet), J.O. Jarløv, Department of Clinical Microbiology, Herlev and Gentofte Hospitals, H.B. Borgeskov, P.D. Cramon, Quality and Development, Region Zealand, J. Engberg, Department of Clinical Microbiology, Slagelse Hospital, H.C. Schønheyder, Department of Clinical Biology, Aalborg University Hospital, J.Y. Blom, Infection Control, North Denmark Region, S. Ellermann-Eriksen, Department of Clinical Microbiology, Aarhus University Hospital, L.N. Hansen, Corporate Quality, Regionshuset Viborg, Central Denmark Region, J.K. Møller, Department of Clinical Microbiology, Lillebælt Hospital, Vejle Hospital, A. Holm, L. Andersen, Department of Clinical Microbiology, Odense University Hospital)

Study of the vaccination coverage for the 5-year booster in Copenhagen

Statens Serum Institut (SSI) has studied the degree of under-reporting of the 5-year booster in the Danish Vaccination Register (DVR) and the causes of missing registration/vaccination with the vaccine among children in the Municipality of Copenhagen.

In Denmark, the coverage of the childhood vaccination programme is generally high, but coverage varies between vaccines and socio-demographic factors. The vaccination coverage is presented at the SSI website. Coverage is high for the vaccines given early in life, whereas coverage for vaccinations given at 4-5 years of age is lower. The aim of the study was to determine the degree of under-reporting to the DVR and to identify causes of missing vaccination with the 5-year booster (re-vaccination against diphtheria, tetanus, whooping cough and polio at 5 years of age). Socio-demographic determinants for lacking vaccination/registration in the DVR were also studied. These determinants included family, ethnicity, child’s area of residence, and the child’s birth order among siblings.

We conducted a cross-sectional study including all children born in 2010 and residing in the Municipality of Copenhagen. The Municipality of Copenhagen was chosen because it is among the municipalities with the lowest vaccination coverage, and the 5-year booster is among the vaccinations with the lowest coverage. All parents of children who were not registered with a 5-year booster in the DVR received a questionnaire on their childs vaccinations. Based on the answers to the questionnaire, an adjusted vaccination coverage was calculated for children living in Copenhagen who were born in 2010. For the entire group of children, socio-demographic determinants for missing vaccination/registration in the DVR with the 5-year booster were assessed in a multivariate logistic regression model calculating odds ratios (OR) and corresponding 95% confidence intervals.

A total of 6,039 children were born in 2010 and resided in the Municipality of Copenhagen when the data were analysed. Among these, 692 (11%) were not registered in the DVR with the 5-year booster. This corresponds to an 89% vaccination coverage. Of the 692 children who were not registered with a 5-year booster in the DVR, 49% participated in the questionnaire study. More than half (55%) stated that their children had, in fact, been vaccinated - two out of three at their GP and one out of three abroad. The vaccination coverage may be adjusted from 89% to a minimum of 91%.

Among the children who had not been vaccinated, the most frequently stated causes were forgetfulness (31%), that the parents had opted out of having their child vaccinated (26%) and that the family had moved to Denmark from another country and had not been aware of the Danish vaccination programme (17%).

In a sub-analysis, we calculated under-reporting of vaccinations given before the 5-year booster. The vaccination coverage of these vaccinations may be adjusted upwards by 0.4-1.1 percentage point, depending on the type of vaccination.

In the study of socio-demographic determinants, there were increased odds of not being registered with the 5-year booster for the following factors: mother’s age <25 years at birth, children with two or more older siblings, children living alone with one of the parents or where parents did not have joint custody. In particular, the OR was increased if the child was an immigrant (OR 10.78); but being a descendant to immigrants or having one Danish and one non-Danish parent also increased the risk. A considerable part of the explanation for this fact is that vaccinations given abroad were not registered in the DVR. If all vaccinations given to immigrants abroad had been recorded in the DVR, this alone would increase the vaccination coverage by one percentage point, from 89% to 90%.

Thus, the study documents an under-reporting to the DVR for the 5-year booster and for for the remaining vaccines in the programme. For the 5-year booster the vaccine coverage could be adjusted 2 percent points. A similar study from 2013 found that the coverage for the 5-year booster could be adjusted with 3-4 percentage point . This means that the correctness of the DVR has probably increased. This may, among others, be explained by the reminder letters that have been sent out by Statens Serum Institut as from 2014 in case of missing vaccination/registration of vaccination in the DVR.

An increased attention on children from large families, children who live with only one of the parents or where the parents do not have joint custody, and on children of non-Danish parents is warranted. The attention should be directed towards checking these children's vaccination status, administrating the missing vaccinations and, not least, towards updating the missing information in the DVR. An accurate monitoring of national level vaccination coverage is important as it may inform decisions about any measures needed to increase the coverage of the Danish childhood vaccination programme. Parents as well as healthcare workers can add previously given vaccines, e.g. vaccines given abroad, in the DVR via fmk-online. For further information about the DVR, please see the Danish Health Authority’s “Questions and answers about the DVR” (In Danish language).

Furthermore, from 1 August 2019 a new reminder system will become operational. The parents or guardians of children will receive an e-Boks reminder before the recommended time for vaccination, informing them that it is now time to get a doctor’s appointment to receive the vaccination. Because it is often difficult to interpret vaccination certificates from other countries and adapt the child’s vaccinations to the Danish childhood vaccination programme. A guideline for the adaptation to the Danish childhood vaccination programme is available at the SSI website.

Additionally, healthcare workers have access to advice by phone or in writing from the Department of Infectious Disease Epidemiology and Prevention at phone +45 3268 3037 Monday-Friday 8.30-11.00 a.m., apart from Wednesday when the phone is manned 12.30-3.00 p.m., or by writing to the e-mail address

(S. Voss, I.G. Helmuth, P. Valentiner-Branth, Department of Infectious Disease Epidemiology and Prevention)