Biomedical subjects

Bernard Fritzell

Publications and source records attributed to Bernard Fritzell.

7 recordsLinked to original sources

PubMed2006

Brief review of the clinical effectiveness of PREVENAR against otitis media.

Pre-licensure trials in Finnish and US infants demonstrated that PREVENAR was associated, respectively, with a 6% (95% CI, -4% to 16%) and an 8.9% (95% CI, 5.8-11.8%) overall reduction in clinical AOM incidence. Long-term follow-up of these cohorts revealed that there was an approximately 10-50% vaccine efficacy against recurrent otitis media or for the prevention of tympanostomy tube placement. In surveillance reports from the USA that followed infants with serious AOM, generalized PREVENAR vaccination led to an important fall in the incidence of pneumococcal otitis media, particularly for cases that would have been frequent or would have been refractory to antibiotic treatment. The rate of pneumococcal MEF isolates fell by 39% for severe otitis media [McEllistrem MC, Adams JM, Patel K, Mendelsohn AB, Kaplan SL, Bradley JS, et al. Acute otitis media due to penicillin-nonsusceptible Streptococcus pneumoniae before and after the introduction of the pneumococcal conjugate vaccine. Clin Infect Dis 2005;40(12):1738-44], by 42%, among persistent or treatment-resistant otitis media [Casey JR, Pichichero ME, Changes in frequency and pathogens causing acute otitis media in 1995-2003. Pediatr Infect Dis J 2004;23(9):824-8 [see comment]] and by 66% among severe otitis media cases or from 'otitis-prone' children [Block SL, Hedrick J, Harrison CJ, Tyler R, Smith A, Findlay R, et al. Community-wide vaccination with the heptavalent pneumococcal conjugate significantly alters the microbiology of acute otitis media. Pediatr Infect Dis J 2004;23(9):829-33 [see comment]].

Child↗

PubMed2006

Indirect effects associated with widespread vaccination of infants with heptavalent pneumococcal conjugate vaccine (PCV7; Prevnar).

Prevnar (heptavalent pneumococcal conjugate vaccine; PCV7) provides protection against invasive pneumococcal disease (IPD) caused by vaccine serotypes. Indirect protection of non-immunised individuals may be the consequence of decreased transmission of vaccine serotypes, generally carried in the nasopharynx of infants and young children. This review summarises published reports of IPD incidence (1998-2005) among non-immunised individuals in countries with universal PCV7 immunisation. Findings suggest that non-immunised individuals benefit from indirect protection following widespread vaccination, enhancing cost-benefit evaluations of vaccination programs. Continued surveillance will be important, to follow future changes associated with non-vaccine type IPD, particularly among individuals with medical co-morbidities that may put them at higher risk of disease.

Adolescent↗

PubMed2006

Impact of pneumococcal conjugate vaccine and of reduction of antibiotic use on nasopharyngeal carriage of nonsusceptible pneumococci in children with acute otitis media.

BACKGROUND: Penicillin resistance among pneumococci has increased in the past 15 years. The implementation of widespread vaccination with the heptavalent pneumococcal conjugate vaccine (PCV7) and the reduction of inappropriate antibiotic use could help reduce antibiotic resistance. METHODS: Between September 2001 and June 2004, 89 pediatricians distributed throughout France took part in this prospective study. We obtained 1906 nasopharyngeal swabs for culture from children aged 6 to 24 months with acute otitis media (AOM). At the same time as PCV7 was introduced into the routine immunization schedule, a plan to promote judicious antibiotic use was established. We recorded the frequency of antibiotic use, as well as the dates of immunization with PCV7. RESULTS: The proportion of PCV7-vaccinated children (> or =1 dose) increased from 8.2% (year 1) to 61.4% (year 3). The proportion of children who received antibiotics within 3 months before enrollment decreased from 51.8% in year 1 to 40.9% in year 3 (P < 0.001). Overall pneumococcal carriage and carriage of PCV7 serotypes decreased during the 3-year period by 16% (P < 0.001) and 35% (P < 0.001), respectively. Rates of highly penicillin resistant strains (PRP) decreased yearly: 15.4%, 10.6%, 6.7% (P < 0.001), respectively. Risks for PRP carriage were 4.2% for immunized children who had not received antibiotics, 8.6% for those vaccinated who also had received antibiotics, 10.3% for unimmunized children who had not received antibiotics, and 16.2% for unimmunized children who had received antibiotics (P < 0.001). CONCLUSION: Implementation of PCV7, combined with a reduction in antibiotic use, in a country with a high prevalence of antibiotic-resistant pneumococci appears to have a strong impact on the carriage of penicillin nonsusceptible pneumococci in children with AOM.

Acute Disease↗

PubMed2006

Early appearance of bactericidal antibodies after polysaccharide challenge of toddlers primed with a group C meningococcal conjugate vaccine: what is its role in the maintenance of protection?

The contribution of memory responses after meningococcal vaccination to protection may depend on the rapidity of the response. Toddlers were challenged with a licensed polysaccharide (PS) vaccine 1 year after vaccination with a single dose of meningococcal group C-CRM(197) conjugate (MCC) vaccine at the age of 12 to 15 months. Bactericidal antibodies and immunoglobulin G (IgG) antibodies detected by an enzyme-linked immunosorbent assay (ELISA) were measured before challenge and 4, 7, 14, or 21 Days later ("Days" refer to treatment groups, "days" to sampling days). Among 281 subjects in the intent-to-treat population, 173 per-protocol (PP) subjects were challenged with 10 microg PS antigen and 103 others with a 50-microg PS vaccinating dose. Capsular PS-specific ELISA IgG titers were negligible in baseline samples and increased only twofold within 4 days of PS administration. In contrast, the proportion of PP subjects with serum bactericidal antibody (SBA) titers of >or=1:8 or >or=1:128 increased, respectively, from 41% and 16% before challenge to 84% and 74% at Day 4 and to 100% and 97% at Day 7. Recipients of 50 microg PS responded with similar kinetics but showed a trend toward higher antibody levels. Unexpectedly, 69% of subjects bled on days 2 to 3 already had achieved SBA titers of >or=1:8. The majority of toddlers previously immunized with MCC and challenged 1 year later with PS antigen mounted protective levels of bactericidal antibody within 2 to 4 days.

Antibodies, Bacterial↗

PubMed2006

Pneumococcal conjugate vaccines: emerging clinical information and its implications.

Since 2000, when the first pneumococcal conjugate vaccine was introduced into routine use in the USA, it has had a substantial impact on invasive pneumococcal disease both in the immunized and nonimmunized population. It has also been shown to reduce pneumonia and otitis in young children and has reduced antibiotic nonsusceptible pneumococcal infections. In the USA, three primary doses and a booster dose are recommended (a so-called '3 + 1 schedule'). Some countries have or will soon introduce routine immunization with fewer doses, with either two primary doses and a booster dose ('2 + 1 schedule') or no booster dose ('3 + 0 schedule'). Some serotypes produce less antibody in a two-dose compared with a three-dose primary series. The booster dose may also be important in reducing nasopharyngeal carriage, hence absence of a booster dose may reduce indirect protection. It remains to be seen whether these schedule changes will reduce vaccine effectiveness within the population. Important future developments include extending the number of serotypes included in the vaccine and the possible extension of use into adults in whom indirect protection has been useful, but not as extensive as might be possible with direct immunization.

Child↗

PubMed2002

Time to recommend pneumococcal vaccination for all children in Europe: experience in France.

UNLABELLED: The French decision-making processes for recommendation and introduction of infant vaccination with Prevenar reflect a public health-based dialogue between the Direction Générale de la Santé and Wyeth (Paris-La Défense, France) nurtured by open and ongoing exchanges. Three surveillance programmes are being discussed: (1) to ascertain the future impact of large-scale Prevenar vaccination on invasive pneumococcal disease incidence, (2) to follow the evolution and carriage of pneumococcus and (3) to look at the possibilities to establish an epidemiological surveillance and active "vaccinovigilance" in France (to estimate the number of adverse events that might be expected among the population targeted by the vaccination recommendation). CONCLUSION: in this way, the Direction Générale de la Santé and Wyeth are working towards the implementation of a broad-scale vaccine introduction.

Bacteremia↗

PubMedDate not supplied

[Conjugated vaccines].

Encapsulated bacterial pathogens (e.g. Haemophilus influenzae type b [Hib], Neisseria meningitidis, or Streptococcus pneumoniae) target infants and young children who have lost any protective anti-capsular antibodies supplied maternally and whose immune systems are ineffective against T-independent antigens such as the polysaccharides of the capsule. The polysaccharide-protein conjugate vaccines overcome this limitation by converting the polysaccharide to a T-dependent antigen, which allows a vaccinated infant to mount a protective immune response. Where conjugated vaccines have been introduced into paediatric vaccination schedules, the incidence of invasive diseases caused by Hib, the group C meningococcus, or the pneumococcus has plummeted by at least 80%, a major public health success. Furthermore, surveillance has demonstrated that the conjugate vaccines provide 'herd protection' through their beneficial impact on nasopharyngeal colonisation among vaccinated children. Promising future approaches include enhancement of the number of capsular serogroups targeted by the meningococcal or pneumococcal conjugate vaccines.

Haemophilus Vaccines↗