Editorials

Meningococcal disease and healthcare workers

The risks to healthcare workers are very low

Although Neisseria meningitidis is a relatively uncommon cause of overt infection (2580 notifications in 1998),¹ the horrors of its clinical presentation have stimulated intense media interest, particularly after outbreaks. With the disappearance of many infectious competitors in the latter half of this century, meningococcal disease has become the leading infectious cause of death in childhood and is now the third most common cause of death in children outside infancy (after accidents and malignancy).² The introduction in October 1999 of a serogroup C protein-polysaccharide conjugate vaccine for children and young adults has the potential to reduce significantly the incidence of disease.³ Nevertheless, most cases are caused by serogroup B meningococci, for which no vaccine is available, and the disease will remain prevalent in the United Kingdom. As a result of the dramatic presentation of cases and the high fatality rate the perceived risk of meningococcal disease is high among those who have had contact with a case.

Close contact with nasopharyngeal secretions from a case is necessary for transmission. Therefore secondary attack rates (increased risk relative to the general population) are as high as 1200 in household contacts, 160 in secondary schools, 60 in primary schools, and 1.8 in universities in the days after presentation of the index case.⁴ Despite the perceived risk, however, only a few cases arise from contact with a case and only 0.5% of all cases are associated with family contacts.⁵

A few healthcare workers have very close contact with a patient suffering from meningococcal disease during assessment, resuscitation, and stabilisation. The nasopharynx of patients with meningococcal disease often contains viable organisms at presentation, even after antibiotic therapy in the community with penicillin.⁶ Although the fears of healthcare workers might seem justified, few published reports exist of healthcare workers ^{7 8} or laboratory staff ^{9 10} developing invasive meningococcal disease. However, a recent report from France again highlights this issue: a paediatrician developed meningococcaemia a week after she intubated a comatose child with meningococcal disease.¹¹

Doctors, nurses, and paramedics who are directly exposed to nasopharyngeal secretions or pulmonary oedema from such patients, mainly during airway management (mouth to mouth resuscitation, intubation, and airway toilet), may therefore be at some increased risk of meningococcal disease. Current guidelines in the United Kingdom advise offering antibiotic chemoprophylaxis only to those undertaking mouth to mouth resuscitation.¹² In the United States chemoprophylaxis is recommended for healthcare workers who have had "intensive unprotected contact (without wearing a mask) with infected patients (eg intubating, resuscitating, or closely examining the oropharynx of patients)."¹³

The risk of transmission and disease for healthcare workers with close contact to airway secretions has not been quantified but is probably very low, and this risk should be further reduced after antibiotic chemoprophylaxis. Other healthcare workers who are not directly exposed to nasopharyngeal secretions but otherwise care for the patient are at negligible risk. However, these individuals may be highly concerned, particularly after presentation of a fulminant case. Local consultants in communicable disease provide a valuable role in assessing and explaining the relative risks and the place of antibiotic chemoprophylaxis in this situation.

In the United Kingdom chemoprophylaxis with rifampicin, ciprofloxacin, or ceftriaxone is currently offered for household and kissing contacts of patients with meningococcal infection and for healthcare workers undertaking mouth to mouth resuscitation¹² and is effective in reducing carriage.¹⁴ The offer of antibiotic chemoprophylaxis should be extended to all healthcare workers in the United Kingdom who have direct exposure to nasopharyngeal secretions from a patient with meningococcal infection. The aim of such chemoprophylaxis is to prevent colonisation in recently exposed healthcare workers and thereby reduce the risk of disease, both in the recipients of chemoprophylaxis and in their close contacts. Chemoprophylaxis is not completely effective in preventing disease,¹⁵ so individuals with significant exposure should be advised of the symptoms of the disease.

Ideally, healthcare and laboratory workers who are at occupational risk of exposure to N meningitidis would be offered vaccination, although the number of cases prevented by such a strategy would be very small. The risk of disease in healthcare workers will be reduced even further as the vaccines now available in the United Kingdom reduce hospital admissions for serogroup C disease. Vaccines for large scale prevention of the more prevalent serogroup B strains are not yet available, although early trials in laboratory workers have demonstrated immunogenicity.¹⁶

Until the arrival of new vaccines offers the hope of real protection, antibiotics should be offered to healthcare workers with direct exposure to potentially infected secretions. Those who are afraid of contracting the disease but are not at risk can be reassured.

Andrew J Pollard, clinical fellow. 

Division of Infectious Diseases and Immunology, British Columbia's Children's Hospital and British Columbia Research Institute for Children's and Women's Health, Vancouver, BC V5Z 4H4, Canada (ajpollard{at}compuserve.com)

Norman Begg, consultant epidemiologist. 

PHLS Communicable Disease Surveillance Centre, London NW9 5EQ

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