In France, the vaccination schedule (1) for children includes the following:
BCG: from the first month. At this age, immunisation is reserved
for children living in environments at risk. It becomes mandatory when
children enter a community (nurseries, schools, and when cared for by
Diphtheria, tetanus, pertussis, poliomyelitis, invasive infection
of Haemophilus influenzae b (combined vaccine): starting at 2 months
of age, 3 injections at one month interval, and a first booster dose
at 16-18 months. A second booster is planned at 6 years of age for diphtheria,
tetanus, and poliomyelitis.
Hepatitis B: from 2 months of age, 2 injections at a month interval,
then a third injection between 5 and 12 months after the second injection.
Measles, mumps and rubella: from 12 months of age, a 1st dose,
and a second dose between 3 and 6 years of age. Measles immunisation
can be administered from the age of 9 months for children living in
community followed by a revaccination with the triple vaccine 6 months
Immunisation against diphtheria, tetanus and poliomyelitis (DT
polio) and BCG are mandatory. All the others are subject to recommendations.
The results of an immunisation programme are assessed not only through
the surveillance of the incidence of target diseases, the population's
serological status, the follow-up of potential adverse effects of vaccines,
but also by the regular evaluation of vaccine coverage rates in the
population, allowing to monitor progress of the objectives set. Moreover,
for diseases in the phase of elimination, this measure should allow
to identify rapidly any decrease of vaccine coverage that could lead
to a disease re-emergence.
The evaluation of vaccine coverage is different depending on age and
antigens as shown by the work coordinated by the Institut de veille
sanitaire in 2000 assessing the methods used (2). The results of the
main measures taken in children up to 6 years of age are described in
Vaccine coverage assessment
The assessment of vaccine coverage is carried out from health certificates
of the 24th month (CS24), filled by each doctor during the examination
that is mandatory before the 24th month of age (3). Since 1985, the
antigens concerned are: DT, pertussis, polio (3 and 4 doses for these
4 antigens), BCG, measles and rubella, and since the update of health
certificates to the new immunisation schedule in 1996, mumps, hepatitis
B, Haemophilus influenzae type b infections.
Data is analysed at the local authority level through the services of
maternal and infant protection (PMI), then at the national level by
the Directorate of Research, Studies, Evaluation and Statistics (DRESS)
of the Ministry of health (4).
Another calculation is carried out by the PMI services in children aged
between 3 and 4 from the data collected on the children's health records
during the mandatory health assessment for nursery schools. This assessment
concerns BCG, measles, and mumps and rubella (3).
Until 1999, a biennial survey was carried out in 6-year-old children
attending their last year in nursery school by doctors and nurses from
the National Education Ministry. The size of the sample was calculated
to allow for representative results at national, regional and local
levels. The analysis concerned antigens for measles, mumps, rubella,
and the last two surveys included antigens for BCG too (5,6). Since
2000, a triennial cycle of surveys has been set up in schools for three
generations of children (6, 10, and 15 years). These surveys deal with
all the antigens that the child should have received from the immunisation
schedule. The first survey on six-year-old children is still ongoing.
Population surveys were carried out on samples by research companies:
one of them was repeated every six months until the end of 1998 to evaluate
hepatitis B vaccine coverage (7). The sample was calculated to be representative
by age groups, one year old in children (5-10 years in adults), for
20 000 families. This method was also used in 1998 to estimate MMR vaccine
coverage in children aged 0 to 15 years together with the number of
doses received (8).
The results are presented here antigen by antigen. They come from DRESS
data for 2000, unless otherwise specified. Table 1 describes the trends
of results for the coverage of children aged less than 24 months for
all antigens from 1992 to 2000. Between 363 000 and 444 000 certificates
for vaccination coverage, depending on the year, were analysed over
this period, representing from 51% to 60% of all expected certificates
for the following cohorts of children aged two (57% in 2000).
BCG vaccination is administered to 83% of children aged 24 months, and
93% of children aged four in nursery schools. The survey carried out
in 1997 in schools shows that 95% of children were vaccinated before
they were six (5).
DT Polio and pertussis
DT Polio vaccination: 98% of children received three doses before two
years of age, and 88% received three doses and a booster. Pertussis
coverage was 97% for 3 doses and 87% for 3 doses and one booster. Figure
1 shows the evolution of vaccine coverage in 24 months old children
for DT Polio vaccination from 1985 to 2000 with a high coverage level
for both 3 and 4 doses. Figure 2 shows the coverage distribution (4
doses) by department with a few areas where coverage is under 85%, in
particular in the south of the country.
Vaccine coverage for measles, mumps and rubella (1st dose) was 84% at
24 months of age and 91% at 4 years in 2000. The last survey carried
out in school children aged 6 showed a 90% coverage in 1999 (for the
same generation of children aged 4 years, it was estimated to be at
around 88% in 1997 by the PMI services) (3,6).
Figure 3 shows the evolution of vaccine coverage in 24 month old children
for measles and rubella from 1985 à 2000, with a rapid increase
of coverage until 1994 which now stabilises. Figure 4 shows differences
in MMR coverage by department in 2000 with rates of coverage higher
in the northern half of France.
Haemophilus influenzae b
Since the introduction of Hib immunisation in 1992, vaccine coverage
has increased quite rapidly; it was 86% in 2000.
Coverage in children under 2 years of age was 26%. At the end of 1998,
the latest estimation of vaccine coverage for hepatitis B in the population
showed that 35% of children ages from 1 to 6 were vaccinated (7).
Comparison with the European Union countries and the United States
Table 2 compares data available on vaccine coverage in children under
2 years of age (3 doses for DTPC, Hib and HBV, 1 dose for measles),
without any details of the calculation method used. The mandatory or
recommended nature of vaccination is given (9,10). The comparison of
this data reveals that France has a high level of vaccine coverage,
similar to that of Nordic countries for diphtheria, pertussis, tetanus
and poliomyelitis. However, coverage levels are not as good for vaccination
against Haemophilus influenzae b infections, and in particular measles
and hepatitis B.
The use of CS24 forms to evaluate vaccine coverage raises some concern
about factors that may affect the results, causing a lack of completeness:
the quality of information given in forms, their transmission by the
doctor who administers vaccines to the health department, their analyses
by each department, and their dispatching at national level. For each
year, only 50 to 60% of expected certificates could be analysed at the
national level. The results of local cluster sample surveys (WHO method)
carried out at home in several districts (11) and the cohesion with
survey analyses carried out at 4 and 6 years enable validation of the
data analysed routinely on the CS24 (3,5,6).
Vaccine coverage for 2 year old children is high, in particular for
DT, poliomyelitis. Except for a case of diphtheria which occurred in
2002 one month after a young woman arrived from China, no case of diphtheria
or autochthonous poliomyelitis has been reported since 1989 (probably
linked with a good group immunity). However, persisting cases of tetanus
in older population1 suggest a bad practice of boosters in adults. We
observe a persisting circulation of pertussis bacteria with the description
of cases in older children and adults. This is not explained by the
lack of coverage, which is high, but by a deficient duration of protection
given by the vaccine. This caused a change in the immunisation schedule
with the introduction of a booster dose at 11-13 years in 1998. For
BCG, the coverage rates reflect the vaccination policy, with a catch-up
dose occurring when children enter school.
Satisfying coverage rates have been reached for vaccination against
Hib infections, associated with a sharp decrease of meningitis incidence
in infants under one year of age2.
Vaccine coverage for measles, mumps and rubella is insufficient, remaining
around 83% for several years. The situation is even more worrying in
southern districts with coverage under 80% and even under 70%. The continual
lack of coverage allows for viruses to circulate resulting not only
in insufficient control of the diseases in children but also in a shift
of cases from childhood to adolescence and adult age and an increased
risk of complications 3.
In 1994, an immunisation programme for adolescents and infants against
hepatitis B was set up. The coverage rates of the 1998 survey show that
the mass immunisation policy led between 1994 and 1998 for children
entering secondary school had reached and even exceeded its objectives
(7). However, the reporting of demyelinising pathologies in persons
vaccinated against hepatitis B raised serious concern. Although no study
has ever revealed any causal association between vaccination and the
occurrence of a first demyelinising stroke, and despite the fact that
infants immunisation was not questioned, vaccine coverage of 24 months
old children does not exceed 26%.
The analysis of the vaccine coverage data in France shows higher numbers
in the north of the country compared to the south. A study published
in 1999 showed that doctors from the south of France were less sensitive
to vaccination practices and that anti-vaccine leagues are more present
(12). The results are in favour of a higher coverage for mandatory vaccines
(diphtheria, tetanus, polio, BCG) than for recommended vaccines (MMR,
hepatitis B), with 83% to 98% for mandatory vaccines versus 26% to 84%
for vaccines recommended before the age of 2. Pertussis and Hib vaccines,
although recommended, have a similar level of coverage as vaccines for
diphtheria, tetanus and poliomyelitis as those 5 vaccines are combined
in a unique vaccine preparation.
However, the conclusions of such a comparison as regards the influence
of mandatory immunisation on vaccine coverage have to be considered
cautiously. Indeed, diphtheria, tetanus and polio immunisation was introduced
in the 1940s to 1960s, when these diseases represented very dangerous
infections and were perceived as such by medical staffs and families.
Immunisation against measles, mumps and hepatitis B, introduced more
recently in the schedule as a recommendation, has not reached comparable
levels of coverage in infants. These diseases don't seem to be considered
as representing a large-scale threat. However the launch of a hexavalent
vaccine could have a positive effect on Hepatitis b vaccine coverage.
International comparisons must be interpreted with care considering
that socio-cultural factors and the organisation of health systems (in
particular the proportion of private and public sectors) influence considerably
the vaccine coverage. The analysis of MMR vaccine coverage shows that
northern European countries where no mandatory immunisation policy was
ever implemented and where vaccines are administered through public
health facilities, have on average better performances than southern
European countries where most of mandatory immunisation was set up and
where the proportion of the private sector is higher. Some countries
without any legal obligations have implemented incentive programmes
like in England, active follow-up of children from birth in the Netherlands,
or the obligation to be immunised before school entry like in the USA.
Adapting the immunisation schedule according to the latest immunological
and epidemiological findings, and the appearance of new vaccines for
children reveal the need to reconsider the measures of vaccine coverage
and the 'key' ages to that end. In France, the implementation of surveys
in schools for children aged 6, 10, and 15, will enable to complete
the available data and to evaluate the administration of the second
MMR dose as well as the boosters for other vaccines.
Finally, regarding MMR and hepatitis B immunisation, it is necessary
to increase vaccine coverage in infants and to ensure an efficient catch
up immunisation in children and in young girls for rubella in the near