No 23b - 2012

MMR vaccination coverage 2011

Vaccination coverage was calculated on 16 April 2012 on the basis of person-identifiable data from the national Childhood Vaccination Database. The Database consists of person-identifiable data from GPs' settlements with the National Health Insurance. The reported coverage thus only includes vaccinations performed in Denmark by GPs. There is a 2-3 month delay from a vaccination is administered until it is registered in the database. For some birth cohorts, vaccination was expected not to have been concluded at the calculation date.

In the 2010 birth cohort, this was the case for MMR1. Furthermore, in the 2007 and 1999 cohorts, MMR2 vaccination was expected not to have been concluded at four and 12 years of age, respectively. As from 1 April 2008, MMR2 vaccination was advanced to the 4-year-examination, EPI-NEWS 9/08. Children who were older than four years by 1 April 2008 should still receive the MMR 2 vaccination at 12 years of age. Until April 2016, MMR2 vaccination will be offered to two birth cohorts every year, those aged 4 and 12 years, respectively.

MMR 1

Vaccination coverage for the birth cohorts 1996-1997 was 85-87%. Coverage in the 1998-2005 birth cohorts was 89-90%, and in the 2006-2009 cohorts it was 88%, Figure 1. For the 2010 birth cohort (67%), vaccination was expected not to have been concluded at the calculation date.

For birth cohort 2007-2009, the lowest MMR1 coverage was seen in the City of Copenhagen, i.e. the municipalities of Copenhagen, Frederiksberg, Tårnby and Dragør. Coverage did, however, increase with the 2009 birth cohort, Table 1.

The 2009 increase was primarily owed to a 3 percentage point rise in the Municipality of Copenhagen.

Data detailing coverage at the municipal level are available at www.ssi.dk/data as figures and map views. Data demonstrate that for birth cohorts 2007-2009, coverage was at its lowest in the municipalities of Samsø (74-82%), Lolland (77-82%) and Tønder (80-82%), while the highest coverages were seen in Skanderborg (91-92%), Køge (90-92%) and Lejre (90-92%).

Calculation of municipal level coverage is sensitive to the size of municipalities.

MMR2 at 12 years

Overall, MMR2 coverage remained unchanged with respect to the previous report, EPI-NEWS 21/11.

Vaccination coverage for birth years 1992-1998 was 85-88%. For birth cohort 1999, coverage was only 81% which may be due to delayed vaccination, Figure 1.

For birth cohort 1999 coverage was at its lowest in the municipalities of Læsø (52%), Svendborg (67%) and Fåborg-Midtfyn (69%), while the highest coverages were recorded in the municipalities of Vesthimmerland (89%) and Sorø, Ringkøbing-Skjern and Brønderslev-Dronninglund (88%).

MMR2 at 4 years

For those who have followed the programme, i.e. the 2004 birth cohort born after 1 April, coverage was 69%. This coverage, however, is artificially low as no correction has been made to adjust for the fact that ¼ of the cohort was not offered MMR2 vaccination.

Vaccination coverage for birth cohorts 2005-2006 was 79%. For birth cohort 2007, coverage was 71% which may be explained by delayed vaccination. For this birth cohort, municipal level coverage ranged from 34% to 81%.

Commentary

MMR vaccination coverage generally remains unchanged and low across Denmark, EPI-NEWS 21/11, and even followed a slightly decreasing trend for the 2006-2009 birth cohorts.

As previously, MMR2 coverage was generally lower than MMR1 coverage. Particularly, MMR vaccination given at four years has not yielded the expected increase in coverage, EPI-NEWS 9/08 and Figure 1.

Despite that real coverage may be under-reported (for MMR1 in birth years 2000-2003 under-reporting may be nearly 3-4 percentage points), EPI-NEWS 20/12, the many years with a less than satisfactory coverage and delay with respect to the recommended MMR vaccination time means that the number of unprotected children and adolescents increases continually. As a consequence, in 2011 Denmark witnessed the largest measles outbreak in the past 16 years including 84 confirmed cases, EPI-NEWS 24/11.

Unless the MMR1 and MMR2 coverage improves markedly, recurring measles outbreaks should be expected. Furthermore, Denmark will be unable to eliminate measles, a 2015 WHO objective for Europe. To fulfil this objective a constant minimum 95% vaccination coverage combined for the two vaccines is needed.

Hopefully, the current offer of free MMR vaccination to young non-immune adults, which will be in place for the rest of 2012, and the National Board of Health's information efforts targeting parents to 4-5-year-olds, EPI-NEWS 12/12, will be instrumental in convincing more citizens to accept the offer of MMR vaccination so that major outbreaks may be avoided in the future.

(P.H. Andersen, L.K. Knudsen, P. Valentiner-Branth, Department of Infectious Disease Epidemiology) 

6 June 2012