Meningococcal carriage in adolescents in the United Kingdom to inform timing of an adolescent vaccination strategy.

OBJECTIVES: Recent development of serogroup B meningococcal (MenB) vaccines highlights the importance of pharyngeal carriage data, particularly in adolescents and young adults, to inform implementation strategies. We describe current UK carriage prevalence in this high risk population and compare methods of carriage detection. METHODS: In this multisite study, pharyngeal swabs were collected on 3-4 occasions over 6-12 months, from 1040 school and university students, aged 10-25 years. Meningococcal carriage was detected by standard culture combined with seroagglutination or PCR of cultured isolates, or by direct PCR from swab. The factor H binding protein (fHBP) variants present in meningococcal isolates were determined. RESULTS: Meningococcal serogroups B and Y were most common, with carriage up to 6.5% and 5.5% respectively, increasing throughout adolescence. Identification by seroagglutination was often unreliable, and the sensitivity of direct PCR detection was 66% compared to culture combined with PCR. Of MenB isolates, 89.1% had subfamily A variants of fHBP. The acquisition rate of MenB carriage was estimated at 2.8 per 1000 person-months. CONCLUSIONS: If vaccination is to precede the adolescent rise in MenB carriage, these data suggest it should take place in early adolescence. Studies assessing vaccine impact should use molecular methods to detect carriage.

Review of diphtheria, tetanus and pertussis vaccines in clinical development.

Diphtheria, tetanus and pertussis vaccines have formed the cornerstone of childhood immunization programs for decades. Historically, these have comprised diphtheria and tetanus toxoids combined with inactivated whole-cell pertussis. More recently, advances have been made with the development of purified acellular pertussis vaccines, with improved reactogenicity profiles, and formulation with additional vaccines such as Haemophilus influenzae type b, hepatitis B virus and inactivated poliovirus. Development is currently focused on maximizing the number of vaccines that can be combined in a single formulation and strategies to provide protection against pertussis before the commencement of routine infant immunization.

Comparison of two combined vaccines against typhoid fever and hepatitis A in healthy adults.

A prospective, randomised, observer-blind, comparative study was performed in healthy adults with a new hepatitis A/typhoid combined vaccine, Viatim, and the marketed Hepatyrix vaccine. Both vaccines induced high levels of protective antibodies, but typhoid responses were higher and hepatitis A responses more rapid with Viatim compared with Hepatyrix. Both vaccines were well tolerated, no serious adverse events (SAEs) occurred, but more Viatim vaccinees had more mild or moderate local reactions (82.7%) than Hepatyrix (53.1%, p < 0.001). In this direct comparison Viatim induced more local reactions, but elicited a more rapid and higher immune response to both antigens than Hepatyrix.

Occurrence of adverse events following inadvertent administration of childhood vaccines.

As a service to healthcare professionals, Aventis Pasteur MSD UK Ltd. operates a telephone-based Vaccine Information Service, providing information on all aspects of vaccination. In the UK it is the primary means by which spontaneous adverse drug reaction reports are received by the company. It was brought to the attention of the Pharmacovigilance Department that a significant number of calls related to people seeking advice following inadvertent administration of vaccines. To inform our advice it was decided to collect details of such episodes, to enquire whether an adverse drug reaction had already occurred, and to encourage reporting of adverse drug reaction that may occur subsequently. Inadvertent vaccination during pregnancy was not included in this survey since these data were already being collected separately. During the period from 1 September 1999 to 31 August 2000 the Vaccine Information Service received 124010 enquiries. Of these, 302 (0.2%) concerned inadvertent administration of one or more vaccines (all age groups), 161 (53.2% of total inadvertent administration) of them in children (<18 years). These 161 reports involved the inadvertent administration of 221 vaccines. In six cases (3.8%) one or more adverse drug reaction were reported following the inadvertent administration. Five of these six cases involved a DTP-containing vaccine: one case where DTP was given instead of diphtheria and tetanus toxoid (DT) vaccine as a pre-school booster, one case where a fourth dose of DTP-Haemophilus influenzae type b conjugate vaccine (Hib) was given at 20 weeks of age and three cases where DTP was mixed with DTP-Hib. The sixth case involved a child given an adult dose of hepatitis B vaccine. Data are available for five of these six cases-all adverse drug reactions were non-serious and resolved without sequelae.Inadvertent administration of vaccines in childhood, although worrying for both the healthcare professionals and the parents involved, seems rarely to result in adverse reactions.