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2.
Ned Tijdschr Geneeskd ; 152(2): 66-8, 2008 Jan 12.
Article in Dutch | MEDLINE | ID: mdl-18265792

ABSTRACT

Notification of laboratory-confirmed pertussis is mandatory in the Netherlands. Thus, the public health service can see to it that timely chemoprophylaxis (within 3 weeks after the onset of symptoms in the index case) is prescribed for all members of the household, should there be a vulnerable non-vaccinated or insufficiently vaccinated newborn in the family. However, it was shown that the delay in this notification was so long that intervention by the prescription of chemoprophylaxis could take place in time to protect a newborn infant in only 10% of the cases. The effectiveness of the notification system in facilitating timely chemoprophylaxis is therefore questioned and it is concluded that other ways to achieve such intervention, independent of notification, are needed. Doctors should always ascertain the presence of a newborn infant in the household of pertussis patients and consider chemoprophylaxis immediately, even ahead of notification. Even if not in time for effective prophylaxis, mandatory notification is still of utmost importance for the evaluation of pertussis immunisation. Surveillance data obtained from notification are used in scenario analysis and contribute to the underpinning of alternative immunisation policies. After all, major improvements in pertussis control can be expected from the addition of (re)vaccination of other target groups, such as mothers of newborns, adolescents or adults, to the national immunisation programme.


Subject(s)
Mandatory Reporting , Pertussis Vaccine/administration & dosage , Whooping Cough/diagnosis , Humans , Immunization Schedule , Infant , Pertussis Vaccine/immunology , Primary Prevention , Time Factors , Whooping Cough/prevention & control , Whooping Cough/transmission
3.
Vaccine ; 26(3): 379-82, 2008 Jan 17.
Article in English | MEDLINE | ID: mdl-18082296

ABSTRACT

BACKGROUND: In November 2006, four Dutch people, aged 53, 58, 80 and 88, died unexpectedly on the day they had received their influenza vaccination. A rapid epidemiological assessment was needed to quantify the risk of a causal association. METHODS: Using routinely available data on age-stratified population size, cardiovascular mortality, and vaccination coverage, a daily rate and daily risk of sudden death per 5-year age-group was calculated. A cumulative probability that at least one person in four specific age-groups would die on the day of vaccination was calculated using a binomial distribution. No assumptions on deaths in other age groups were included. RESULTS: The overall likelihood that at least one person in each of the four age categories 50-54, 55-59, 80-84 and 85-89 would die suddenly on the day of influenza vaccination in the Netherlands was calculated to be 0.016. This was 330 times more likely than nobody dying in each of these categories, and 45 times less likely than the most probable outcome. CONCLUSION: We concluded that there was a small but real chance of the four deaths occurring without a causal link to the vaccination. Policy decisions regarding unexpected deaths following vaccination can benefit from a rapid epidemiological evaluation.


Subject(s)
Death, Sudden , Influenza Vaccines/administration & dosage , Influenza, Human/prevention & control , Aged , Aged, 80 and over , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/mortality , Death, Sudden/epidemiology , Humans , Likelihood Functions , Middle Aged , Netherlands/epidemiology , Vaccination
4.
Ned Tijdschr Geneeskd ; 151(39): 2166-9, 2007 Sep 29.
Article in Dutch | MEDLINE | ID: mdl-17957995

ABSTRACT

The influenza vaccine is considered safe, but information on vaccine-related adverse events is limited and a nationwide overview of adverse events is lacking. In 2006, after deaths occurred in Israel and the Netherlands following influenza vaccination, the Dutch Ministry of Health, Welfare and Sport (VWS) asked the National Institute for Public Health and the Environment (RIVM) twice for a recommendation regarding the continuation of the national vaccination campaign. After 4 deaths were reported in Israel in October 2006 following administration of Vaxigrip, the Dutch vaccination campaign was suspended for one week. One month later, 4 additional deaths were reported after influenza vaccination in the Netherlands. The newly appointed outbreak management team concluded that a causal relationship between vaccination and the deaths was highly unlikely, based on data regarding the individual cases, background mortality rates and prior reports of adverse events. Further suspension of the vaccination campaign was deemed unnecessary this time. A centralised nationwide registry of adverse events has since been established to provide further insight into the incidence of adverse events following influenza vaccination. Physicians are advised to report potential adverse events following influenza vaccination to the Netherlands Pharmacovigilance Centre Lareb (www.lareb.nl).


Subject(s)
Adverse Drug Reaction Reporting Systems , Influenza Vaccines/adverse effects , Databases, Factual , Humans , Israel , Netherlands
5.
Clin Microbiol Infect ; 12(12): 1214-20, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17121628

ABSTRACT

This study analysed the consequences of deviation from the WHO case definition for the assessment of patients with suspected severe acute respiratory syndrome (SARS) in The Netherlands during 2003. Between 17 March and 7 July 2003, as a result of dilemmas in balancing sensitivity and specificity, five different case definitions were used. The patients referred for SARS assessment were analysed from a public health perspective. None of the patients referred had SARS, based on serological and virological criteria. Nevertheless, all 72 patients required thorough assessment and, depending on the results of the assessment, institution of appropriate prevention and control measures. Changing case definitions caused confusion in classifying cases. A centralised assessment of the reported cases by a team with clinical and public health expertise (epidemiological and geographical risk assessment) is a practical solution for addressing differences in applying case definitions. The burden of managing non-cases is an important issue when allocating public health resources, and should be taken into account during the preparation phase, rather than during an outbreak. This applies not only to SARS, but also to other public health threats, such as pandemic influenza or a bioterrorist episode.


Subject(s)
Disease Outbreaks , Population Surveillance , Public Health/standards , Severe Acute Respiratory Syndrome/diagnosis , Severe Acute Respiratory Syndrome/epidemiology , Antibodies, Viral/blood , Communicable Disease Control/methods , Female , Humans , Infection Control/methods , Male , Netherlands/epidemiology , Reference Standards , Resource Allocation , Retrospective Studies , Severe acute respiratory syndrome-related coronavirus/genetics , Severe acute respiratory syndrome-related coronavirus/immunology , Severe acute respiratory syndrome-related coronavirus/isolation & purification , Sensitivity and Specificity , Severe Acute Respiratory Syndrome/prevention & control , World Health Organization
6.
Epidemiol Infect ; 134(3): 579-84, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16238821

ABSTRACT

The distribution of antibody levels to Legionella (L.) pneumophila (serotypes 1-7) was compared between subjects who worked near the source of a large outbreak of Legionnaires' disease (n=668) and a population sample of comparable age (n=480). In a previous analysis of these data, it was estimated that 80% of those working near the source were infected with L. pneumophila. However, the estimation procedure implicitly assumes that the probability of infection does not depend on the antibody level of a person before exposure. This is questionable, as antibodies could protect against infection. We have now estimated the minimum value consistent with the data on the number of infected persons. We observed that a minimum of 40% [95% confidence interval (CI) 32-48] of those working near the source and 13% (95% CI 8-18) of those working further away were infected with L. pneumophila. Implications of these findings for design options in future research are discussed.


Subject(s)
Disease Outbreaks , Legionnaires' Disease/epidemiology , Adolescent , Adult , Aged , Antibodies, Bacterial/blood , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Middle Aged , Occupational Exposure
7.
Epidemiol Infect ; 133(1): 159-71, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15724723

ABSTRACT

High titres of pertussis toxin (PT) antibody have been shown to be predictive of recent infection with Bordetella pertussis. The seroprevalence of standardized anti-PT antibody was determined in six Western European countries between 1994 and 1998 and related to historical surveillance and vaccine programme data. Standardized anti-PT titres were calculated for a series of whole-cell and acellular pertussis vaccine trials. For the serological surveys, high-titre sera (> 125 units/ml) were distributed throughout all age groups in both high- (> 90%) and low-coverage (< 90%) countries. High-titre sera were more likely in infants in countries using high-titre-producing vaccines in their primary programme (Italy, 11.5%; Western Germany, 13.3%; France, 4.3%; Eastern Germany, 4.0%) compared to other countries (The Netherlands, 0.5%; Finland, 0%). Recent infection was significantly more likely in adolescents (10-19 years old) and adults in high-coverage countries (Finland, The Netherlands, France, East Germany), whereas infection was more likely in children (3-9 years old) than adolescents in low-coverage (< 90%; Italy, West Germany, United Kingdom) countries. The impact and role of programmatic changes introduced after these surveys aimed at protecting infants from severe disease by accelerating the primary schedule or vaccinating older children and adolescents with booster doses can be evaluated with this approach.


Subject(s)
Whooping Cough/epidemiology , Adolescent , Adult , Antibodies, Bacterial/blood , Bordetella pertussis/immunology , Chi-Square Distribution , Child , Europe/epidemiology , Female , Humans , Immunoglobulin G/blood , Incidence , Male , Pertussis Vaccine/administration & dosage , Prevalence , Seroepidemiologic Studies , Whooping Cough/prevention & control
8.
Epidemiol Infect ; 132(5): 839-45, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15473146

ABSTRACT

During 1995--1996 a population-based seroprevalence study was conducted in The Netherlands. Risk factors were established for postnatally acquired toxoplasmosis. The results were compared with a study conducted during 1987-1988 in pregnant women in the Southwest of The Netherlands in order to estimate the change in seroprevalence. In total, 7521 sera were tested and the national seroprevalence was 40.5 % (95 % CI 37.5-43.4). Living in the Northwest, having professional contact with animals, living in a moderately urbanized area, being divorced or widowed, being born outside The Netherlands, frequent gardening and owning a cat were independently associated with Toxoplasma seropositivity. Risk factors like eating undercooked meat could not be studied. The seroprevalence among women aged 15-49 years was 10 % lower (35.2 %, 95 % CI 32.9-38.6) in the study of 1995-1996, compared to the Toxoplasma study of 1987--1988 (45.8 %, 95 % CI 45.2-46.3). The steepest rise in seroprevalence still occurred among the subjects aged 25-44 years.


Subject(s)
Pregnancy Complications, Parasitic/epidemiology , Toxoplasma/isolation & purification , Toxoplasmosis/epidemiology , Adolescent , Adult , Age Factors , Aged , Animals , Antibodies, Protozoan/analysis , Cats , Child , Child, Preschool , Disease Reservoirs , Female , Humans , Infant , Male , Middle Aged , Netherlands/epidemiology , Population Surveillance , Pregnancy , Pregnancy Complications, Parasitic/blood , Pregnancy Complications, Parasitic/etiology , Risk Factors , Seroepidemiologic Studies , Soil Microbiology , Toxoplasma/immunology , Toxoplasmosis/blood , Toxoplasmosis/etiology
10.
Vaccine ; 21(7-8): 716-20, 2003 Jan 30.
Article in English | MEDLINE | ID: mdl-12531347

ABSTRACT

The immunity to vaccine-preventable diseases included in the Dutch immunisation programme in the general population and among orthodox reformed individuals who refuse vaccination was assessed. The programme induces good protection. However, a large proportion of adults lacks diphtheria and tetanus immunity. Measles, mumps and rubella seroprevalence was somewhat lower among vaccinated compared to unvaccinated cohorts. The prevalence of HibPS antibodies declined during 2.5 years after the fourth vaccination. However, protection occurs also by memory immunity. Herd immunity is sufficient among the general population, but not among orthodox reformed individuals. Immunosurveillance is an efficient way to evaluate the effects of immunisation programmes and identify risk groups for infection.


Subject(s)
Communicable Diseases/immunology , Immunization Programs/statistics & numerical data , Adolescent , Adult , Aged , Child , Child, Preschool , Communicable Disease Control/statistics & numerical data , Diphtheria/immunology , Diphtheria/prevention & control , Haemophilus Infections/immunology , Haemophilus Infections/prevention & control , Haemophilus influenzae type b/immunology , Humans , Infant , Infant, Newborn , Mass Vaccination/methods , Mass Vaccination/statistics & numerical data , Measles/immunology , Measles/prevention & control , Middle Aged , Mumps/immunology , Mumps/prevention & control , National Health Programs , Netherlands/epidemiology , Poliomyelitis/immunology , Poliomyelitis/prevention & control , Program Evaluation , Rubella/immunology , Rubella/prevention & control , Tetanus/immunology , Tetanus/prevention & control
11.
Vaccine ; 21(7-8): 721-4, 2003 Jan 30.
Article in English | MEDLINE | ID: mdl-12531348

ABSTRACT

We investigated which vaccination schedule gives best protection to the vaccinating population, in case of a measles epidemic in pockets of unvaccinated individuals. We explored the effect of an additional measles vaccination (at 6 or 9 months), advancing the first measles-mumps-rubella (MMR) vaccination from 14 to 11 months, and advancing the second MMR from 9 to 4 years. Measures of protection among vaccinees (percentage of susceptibles, number of reported cases, percentage of lifetime spent susceptible) were estimated with a mathematical model of the impact of antibody level on seroconversion and immunity. Advancing the age of second MMR vaccination prevents considerably more cases among vaccinees than an extra early measles vaccination or advancing the age of first MMR vaccination.


Subject(s)
Immunization Schedule , Measles-Mumps-Rubella Vaccine/administration & dosage , Measles/prevention & control , Child, Preschool , Humans , Infant , Measles/epidemiology , Netherlands/epidemiology
12.
Epidemiol Infect ; 128(1): 47-57, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11895090

ABSTRACT

We investigated which vaccination schedule gives best protection to the vaccinating population, in case there is a measles epidemic in an area with low vaccine coverage. We considered combinations of an early measles vaccination (none, at 6 months or at 9 months), a measles-mumps-rubella (MMR) vaccination around the first birthday (at either 11 or 14 months), and MMR vaccination at an older age (at either 4 or 9 years). The different estimates on measures of protection (percentage of susceptibles, number of reported cases in an epidemic year, percentage of lifetime spent susceptible) relied on a mathematical model of decline of maternal antibody levels with age, and the impact of that antibody level on seroconversion and immunity. Model parameters were estimated from a Dutch population-based serological survey on measles antibodies. Different measures of protection favoured different vaccination schedules, but dropping the age of second MMR vaccination prevents considerably more cases than an extra early measles vaccination or dropping the age of first MMR vaccination.


Subject(s)
Disease Outbreaks , Immunization Schedule , Measles Vaccine/administration & dosage , Measles/prevention & control , Models, Theoretical , Age Factors , Antibodies, Viral , Antibody Formation , Child , Child, Preschool , Female , Forecasting , Humans , Infant , Male , Measles/epidemiology , Measles/immunology , Measles-Mumps-Rubella Vaccine
13.
Euro Surveill ; 4(12): 133-134, 1999 Dec.
Article in English | MEDLINE | ID: mdl-12631880

ABSTRACT

The incidence of pertussis throughout the Netherlands, determined by notifications, rose suddenly in 1996 to reach 27.2 cases per 100 000 population, compared with 2.3/100 000 on average from 1989 to 1995. Earlier increases in 1989-1990 and 1994 reflected

14.
Euro Surveill ; 3(12): 122-124, 1998 Dec.
Article in English | MEDLINE | ID: mdl-12631924

ABSTRACT

The European Advisory Group on Immunisation has recommended that measles should be eliminated from Europe by the year 2007, a target accepted by National Immunisation Programme Managers for the World Health Organization (WHO) European Region countries. I

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