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Meningococcus Meningococcus Meningococcus Last updated: September 5, 2018 Vaccine Preventable Diseases 1 SurveillanceWHO Surveillance Standards of Vaccine-Preventable Diseases Meningococcus DISEASE AND VACCINE CHARACTERISTICS Neisseria meningitidis (Nm) is a gram-negative IMD includes meningitis and septicemia, but Neisseria bacterium that usually resides harmlessly in the human meningitidis can also rarely cause arthritis, myocarditis, pharynx. Under certain conditions, asymptomatic pericarditis, invasive pneumonia, necrotizing fasciitis carriage can progress to invasive meningococcal disease and endophthalmitis. Clinical disease occurs 2–10 days (IMD), resulting in meningitis, fulminant septicemia after infection, and commonly within 3–4 days. Signs or both. The majority of invasive infections are caused of meningitis in older children and adults include fever, by meningococci of serogroups A, B, C, X, W or Y nausea/vomiting, neck stiffness, headache, photophobia capsular polysaccharides. These serogroups can cause and altered mental status, whereas infants have non- both endemic disease and outbreaks, but their relative specific presentation with common symptoms that prevalence varies considerably with time and geographic include fever, poor feeding, vomiting and lethargy. location. In the African meningitis belt (from Senegal Meningococcal septicemia often initially presents in the west to Ethiopia in the east), serogroup A with systemic symptoms and signs of meningitis, has historically been the most important serogroup and progresses to often include a non-blanching causing large epidemics. The recent epidemiology haemorrhagic (petechial or purpuric) rash. Untreated of meningococcal disease in Africa is changing, IMD is often fatal. Even with antibiotic treatment case- particularly in the wake of the introduction of the fatality rates can exceed 10%, and 10–20% of survivors conjugate serogroup A vaccine over the last decade; are left with permanent sequelae such as deafness, in addition, outbreaks caused by serogroups C, W and intellectual disability and amputations due to necrosis of X have occurred more frequently in recent years. In the extremities. Europe, North America and Latin America, serogroups Both plain polysaccharide and protein-polysaccharide B, C and W currently cause the majority of disease, conjugate vaccines are available against meningococci while in Asia, though surveillance data are limited, of serogroups A, C, W and Y. Plain polysaccharide serogroups A and C appear to cause most disease. vaccines can be 2-to-4-valent, and are mostly BOX 1 Surveillance for IMD vs. bacterial meningitis All countries should aim to undertake IMD surveillance, which focuses on cases of IMD based on laboratory confirmation or strict clinical grounds (meningitis or septicemia with characteristic hemorrhagic rash). Effective IMD surveillance depends on laboratory capacity to detect N. meningitidis. These updated surveillance standards focus primarily on surveillance for IMD due to N. meningitidis, which is a change from the 2003 surveillance standards that described syndromic bacterial meningitis surveillance. The change reflects increasing global laboratory capacity and changing meningococcal epidemiology. However, meningitis surveillance should still be implemented in countries with an historically significant burden of bacterial meningitis or limited laboratory confirmation capacity (such as countries of the African Meningitis Belt). Meningitis surveillance should not be targeted at a single pathogen, but should rather include testing for the three main vaccine-preventable bacterial causes of meningitis: N. meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. It should also include other bacterial causes of meningitis, if the lab capacity exists. See Annex A, Bacterial meningitis surveillance. 3 WHO Surveillance of Vaccine-Preventable Diseases administered in campaigns in response to outbreaks as or multivalent. The dosing age and schedule depends a single dose to persons ≥ 2 years of age. Compared to on the serogroup of the vaccine and setting. Mass plain polysaccharide vaccines, protein-polysaccharide campaigns with monovalent serogroup A conjugate conjugate vaccines (hereafter referred to as conjugated vaccine among people aged 1–29 years old in the African vaccines) are more immunogenic, elicit immunologic meningitis belt have resulted in a substantial decrease in memory and are effective in infants as young as 2 meningococcal A disease. A single dose of this vaccine months of age. In addition, repeat doses of conjugated is now being introduced into the routine immunization vaccine boost immune responses in contrast to repeat schedule in these countries. Serogroup B vaccines are plain polysaccharide vaccination, which may lead based on recombinant or purified proteins. to hyporesponsiveness or reduced responses. Most importantly, conjugate vaccines prevent acquisition of carriage. Conjugate vaccines can be monovalent RATIONALE AND OBJECTIVES OF SURVEILLANCE The surveillance system aims to provide reliable and » monitor changes in circulating serogroups timely data to: » monitor antibiotic susceptibility. h detect and confirm cases, which should lead to h measure the impact of control measures, including appropriate public health response vaccine effectiveness and failure h detect and confirm outbreaks h identify geographical areas and populations at risk h describe the epidemiology of N. meningitidis disease in order to implement and adapt adequate control measures. » assess the case burden and incidence trends » monitor the circulation and distribution of specific strains TYPES OF SURVEILLANCE RECOMMENDED h Minimum surveillance in all countries should be Facility-based. Clinicians should also report nationwide and case-based, and should include all ages. probable cases of meningitis or septicemia, as defined The site of case detection should include both of the below. It is important to train clinicians on IMD following: clinical syndrome, including specific recognition of h purpuric skin lesions. Laboratory-based: Laboratories should report confirmed and probable cases based on their findings. 4 Meningococcus Meningococcus CASE DEFINITIONS AND FINAL CLASSIFICATION CONFIRMED IMD CASE h gram-negative diplococci identified from any N. meningitidis is identified via culture or polymerase normally sterile site (blood, CSF) or from a purpuric chain reaction (PCR) from a purpuric skin lesion or any skin lesion normally sterile site (blood, cerebrospinal fluid [CSF] or h N. meningitidis antigen detection (for example, by other fluids such as synovial fluid). latex agglutination testing) from any normally sterile site or from a purpuric skin lesion. PROBABLE IMD CASE Clinical diagnosis of meningitis or septicemia and at Note that because IMD surveillance is based on least one of the following: laboratory findings or a characteristic haemorrhagic rash, there is no suspected case definition. h purpuric rash where IMD is considered the most likely cause (linked to confirmed cases with other causes of haemorrhagic rash excluded or considered less likely) CASE INVESTIGATION All probable and confirmed IMD cases should undergo treatment, search for other cases and identify close thorough epidemiological and laboratory investigation, contacts for control measures such as vaccination or ideally within 24 hours of notification. The goals of chemoprophylaxis. case investigation in this setting are to make sure patients have received or been referred for proper SPECIMEN COLLECTION Specimens to diagnose IMD are collected from VOLUME OF SPECIMENS h any normally sterile site according to the clinical CSF presentation, such as blood or CSF for meningitis » 3 mL in total: 1 mL into each of three test tubes. or sepsis and aspirate or biopsy of haemorrhagic rash for purpuric skin lesions (1). In some settings, • Tube 1: Chemical analysis: protein and meningococcus can be isolated from other specimen glucose tests types such as synovial fluid, but such specimens are • Tube 2: Microbiological tests generally not part of routine surveillance for IMD. • Tube 3: Record overall appearance; perform Care should be taken to minimize any risk of cross- white blood cell count contamination during manipulation or aliquotting. » If only one tube of CSF is available, it should be For example, use sterile dispensing technique with given to the microbiological laboratory appropriate pipettes, tips and tubes. 5 WHO Surveillance of Vaccine-Preventable Diseases h Blood rapid culturing. If there is no access to a microbiology laboratory, inoculated T-I media » 5–10 mL for an adult. As it may be difficult to should be sent from the health facility to the collect more than 3 mL of blood from a child, district or reference laboratory within 24 hours. 1–3mL is considered adequate. Districts should send the inoculated T-I media » Collected blood should be diluted in blood to the national or regional reference laboratory at culture broth in order to obtain blood cultures. least twice a week. It is important to use appropriate ratios of blood h Blood to culture broth for optimal bacterial growth. The recommendations of the culture broth » Specimens should be immediately inoculated manufacturer should be closely followed. Add (within one minute) into a blood culture bottle 1–2 mL of blood from a child to 20 mL of blood and transported to a microbiology laboratory as culture broth. For adults, add 5–10 mL of blood soon as possible for overnight incubation and from
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