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PAPERS: Bjørn-Erik Kristiansen, Yngvar Tveten, and Andrew Jenkins Which contacts of patients with meningococcal disease carry the pathogenic strain of Neisseria meningitidis? A population based study BMJ 1998; 317: 621-625 [Abstract] [Full text]

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Carrage of Neisseria meningitidis and age distribution

Ralf Reintjes   (29 September 1998)

Definition of "Kissing" Contacts

Andrew Hayward   (1 October 1998)

Response to Carriage of Meningococci in Contacts of Patients with Meningococcal Disease

Peter Dutton, Robert Winterton, Ewan Wright, Han San Aw Yeang   (15 October 1998)

Carrage of Neisseria meningitidis and age distribution 29 September 1998
Ralf Reintjes, Medical Epidemiologist in Infectious Diseases National Institute of Public Health and the Environment (RIVM) Send response to journal: Re: Carrage of Neisseria meningitidis and age distribution	Dear Sir, In their study Kristiansen, Tveten and Jenkins used an interesting study design looking for carriers of Neisseria meningitidis among contacts of patients with meningococcal disease[1]. The results show a strong relation between level of contact and prevalence of carriership with the highest prevalence rates among household and kissing contacts. The results are clear and especially the high prevalence of the pathogenic strain of 12.4% among household and kissing contacts are impressive. Nevertheless, it is known that the prevalence of meningococcal carriage is strongly associated with age, following a very typical age distribution, and other risk factors. This has been shown in different studies from various countries, including one from Norway[2]. Peak rates are observed among individuals between 15-30 years of age. From our own experiences, drawn from a recent study following a local outbreak of meningococcal disease in the Netherlands, we know that these factors play a role as risk factors. Here the prevalence of meningococcal carriers in a systematic sample of the general population varied from 3% among the 2- to 5-year-olds to 39% among the 16- to 20-year-olds and was lower among those who had recently been using antibiotics (OR=0.3; 95% CI 0.1-0.9). The prevalence of carriers of the pathogenic strain causing the outbreak in the population was low (0.5%). We wonder whether age as a determinant of carriage has been studied by Kristiansen et al. We would be interested to know to what extent different age distributions within the three contact classes varied from the one in the general population and whether correction for age influenced the prevalence rates within the three groups. Does the prevalence of carriage among class 2 and 3 contacts (non-household and non -kissing contacts) then still exceed the prevalence found in the general population by 2-3 times? And has the effect of other known risk factors as for example crowding or antibiotic use in the weeks previous to the study been evaluated? no conflict of interests Reference: 1. Bj;rn-Erik Kristiansen, Yngvar Tveten, Andrew Jenkins. Which contacts of patients with meningococcal disease carry the pathogenic strain of Neisseria meningitidis? A population based study. BMJ 1998; 317: 621-625 2. Caugant DA, Hoiby EA, Magnus P, et al. asymptomatic Carriage of Neisseria meningitidis in a Randomly Sampled Population. J. Clin. Microbiol. 1994; 32: 323-330 Sincerely, Ralf Reintjes MD PhD and Marina A E Conyn-van Spaendonck MD PhD Department of Infectiouse Diseases Epidemiology National Institute of Public Health and the Environment(RIVM) PO Box 1 3720 BA Bilthoven The Netherlands Fax: **31 30 2744409; Tel: **31 30 2742009; e-mail: Ralf.Reintjes@RIVM.NL
Definition of "Kissing" Contacts 1 October 1998
Andrew Hayward, Lecturer in Public Health Medicine University of Nottingham. United Kingdom Send response to journal: Re: Definition of "Kissing" Contacts	Kristiansen et al demonstrate high carriage rates of pathogenic strains of Neisseria menigitidis in household and kissing contacts of patients with invasive meningococcal disease. Whilst it is relatively easy to define a household contact it may be more difficult to define a kissing oontact. There are many types of kiss ranging from a "peck on the cheek" to much more! In some cultures kissing is as common as shaking hands. In such situations widespread chemoprophylaxis to "kissing contacts" may not be appropriate. It would be valuable to know whether the authors placed any restrictions on who was defined as a kissing contact. Reference Which contacts of patients with meningococcal disease carry the pathogenic strain of Neisseria meningitidis? A population based study Bjørn-Erik Kristiansen, Yngvar Tveten, and Andrew Jenkins BMJ 1998; 317: 621-625
Response to Carriage of Meningococci in Contacts of Patients with Meningococcal Disease 15 October 1998
Peter Dutton, 4th Year Medical Students Department of Epidemiology & Public Health, The Medical School, University of Newcastle., Robert Winterton, Ewan Wright, Han San Aw Yeang Send response to journal: Re: Response to Carriage of Meningococci in Contacts of Patients with Meningococcal Disease	Dear Sir, We read with interest, the report by Kristiansen, Tveten and Jenkins, which addresses important questions about the appropriate use of chemoprophylaxis in contacts of patients with meningococcal disease. However, we feel that the data presented does not fully support their conclusions. They found high carrier rates amongst class I contacts (12.9%), and advocated the use of chemoprophylaxis in this group, based upon their assumption that carrying the pathogenic strain increases the likelihood of contracting the disease. One concern is that this group accounts for only 18 of 42 contacts found to be carriers. Therefore, more than half of carriers would not recieve prophylaxis. Should classes II and III be excluded? We accept that giving prophylaxis to all members of groups II and III seems excessive. However, it would have been interesting if the authors had assessed the characteristics of these carriers to identify those at highest risk and target chemoprophylaxis more effectively. In addition, the carrier rates were compared to those in other Norwegian populations where the definition of pathogenic strain was different (1,2). It would have been more appropriate to compare their carrier rates with the prevalence amongst non-contacts of meningococcal disease in the Telemark area. In conclusion, this paper fails to conclusively determine appropriate chemoprophylactic strategy. It also highlights the fact that there is still much to learn about the relationship between carriage of meningococci and meningococcal disease. Yours Sincerely, REFERENCES: 1. Kristiansen BE, Lind KW, Mevold K, Sorensen B, Froholm LO, Bryn K, et al. Meningococcal disease: studies of bacterium phenotypic and genomic characteristics and of human antibody levels. J Clin Microbiol. 1988; 26:1988-1992. 2. Caugant DA, Hoiby EA, Magnus P, Scheel O, Hoel T, Bjune G, et al. Asymptomatic carriage of Neisseria meningitidis in a randomly sampled population. J Clin Microbiol. 1994; 32:323-30.