Fiona R. M. van der Klis

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BACKGROUND In many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined(More)
BACKGROUND In 2002 a Meningococcal serogroup C (MenC) conjugate vaccine, with tetanus toxoid as carrier protein, was introduced in the Netherlands as a single-dose at 14 months of age. A catch-up campaign was performed targeting all individuals aged 14 months to 18 years. We determined the MenC-specific immunity before and after introduction of the MenC(More)
BACKGROUND Environmental enteropathy (EE) is a subclinical enteric condition found in low-income countries that is characterized by intestinal inflammation, reduced intestinal absorption, and gut barrier dysfunction. We aimed to assess if EE impairs the success of oral polio and rotavirus vaccines in infants in Bangladesh. METHODS We conducted a(More)
OBJECTIVE This study evaluates trends in antibody seroprevalences of seven high-risk human papillomavirus (hr-HPV) serotypes (HPV16, 18, 31, 33, 45, 52, and 58) between the 1995-96 and 2006-07 sero-surveys among the Dutch general population in the pre-vaccination era. METHODS Serum samples of men and women (0-79 years of age) from two cross-sectional(More)
Background: Bordetella pertussis can cause severe respiratory disease and death in children. In recent years, large outbreaks have occurred in high-income countries; however, little is known about pertussis incidence in sub-Saharan Africa. Methods: We evaluated antibody responses to pertussis toxin (Ptx) from individuals aged between 2 and 90 years in rural(More)
OBJECTIVES In order to assess HPV-specific IgG characteristics, we evaluated multiple aspects of the humoral antibody response that will provide insight in the HPV humoral immune response induced by HPV infection and vaccination. METHODS Cross-reactivity of HPV-specific antibodies induced by infection or vaccination was assessed with VLP16 or 18(More)
BACKGROUND To monitor the impact of human papillomavirus types 16 and 18 vaccine on HPV infection dynamics in the Netherlands, we started an ongoing study in sexually transmitted infection (STI) clinics in 2009. Here, we analyze baseline type-specific HPV DNA and HPV-specific antibody positivity rates. METHODS We enrolled 3569 men and women, 16-24 years(More)
BACKGROUND All children and adolescents between 1 and 19 years of age in The Netherlands received a single meningococcal serogroup C conjugate (MenCC) vaccine in 2002. During follow-up 4-5 years later, the persistence of MenC polysaccharide-specific IgG was found to be dependent on age of vaccination with higher IgG levels in the oldest immunized age(More)
Here we present mumps virus specific antibody levels in a large cross-sectional population-based serosurveillance study performed in the Netherlands in 2006/2007 (n = 7900). Results were compared with a similar study (1995/1996) and discussed in the light of recent outbreaks. Mumps antibodies were tested using a fluorescent bead-based multiplex immunoassay.(More)
The effects of single or multiple concordant HPV infections at various anatomical sites on type-specific HPV seropositivity are currently unknown. In this cross-sectional study we assessed whether high-risk HPV infections at various anatomical sites (i.e., anal canal, penile shaft, and oral cavity), as well as concordant infections at multiple anatomical(More)