Aviso Epidemiológico: Hepatitis Aguda Grave de Causa Desconocida en Niños

Objectives

The notice establishes an emergency surveillance and response framework for severe acute hepatitis of unknown cause in children, directed at first-, second- and third-level medical units, Hospital Epidemiological Surveillance Units and the National Public Health Laboratory Network.[1]Its central purpose is to identify, investigate, classify and follow suspected and probable cases in people aged 16 years or under, while maintaining surveillance for viral hepatitis and investigating a potential infectious aetiology.[2][3]A formal mission statement, long-term strategic goals and budgeted programme areas are not specified.[2][4]

• Identify suspected cases of acute hepatitis without a known cause in people aged 16 years or under, including those with aspartate aminotransferase or alanine aminotransferase concentrations above 500 international units per litre.[2]
• Classify probable cases where testing by the National Institute of Epidemiological Diagnosis and Reference, known as InDRE, excludes hepatitis A, B, C, D and E.[2][3]
• Investigate the epidemiological pattern of illness, including temporal and geographical associations, contacts and possible pathogen genetic characterisation.[3]
• Strengthen timely notification, laboratory investigation and continued conventional surveillance of viral hepatitis through the National Epidemiological Surveillance System.[2][3]
• Promote infection prevention and control, hand hygiene, sanitation, food safety, safe drinking water and completion of hepatitis vaccination schedules.[3][5]

The framework responds to an international event in which the cause had not been identified as of 19 May 2022, although adenovirus was the principal hypothesis under investigation.[1]Reported cases were characterised by acute hepatitis with substantially raised transaminases, commonly jaundice and gastrointestinal symptoms, while hepatitis A to E viruses had not been detected.[6]By 21 April 2022, at least 169 cases in children aged from one month to 16 years had been reported from 12 countries, including one death; 10% had required liver transplantation.[1][6]

Implementation

Implementation relies on an integrated national surveillance, referral and laboratory pathway linking health-care providers, sanitary jurisdictions, state epidemiology services, federal authorities and public-health laboratories.[2][3]The General Directorate of Epidemiology, known as DGE, oversees follow-up through its Epidemiological and Health Intelligence Unit and its directorates responsible for surveillance of communicable and non-communicable diseases.[4]Probable cases remain under investigation until a final diagnosis, and each is reviewed by an expert group.[3]

• Notify cases from medical units to the relevant sanitary jurisdiction through the SUIVE-2 Epidemiological Case Investigation Form; require public-sector services also to inform their immediate institutional superior and private services to notify through the jurisdiction.[2]
• Transmit case information from the state epidemiology area to the federal level, accompanied by laboratory findings and a clinical summary.[2]
• Submit serum, anticoagulated blood, stool and throat-swab specimens through the State Public Health Laboratory Network, known as LESP, to InDRE under refrigerated conditions; obtain lung or liver tissue in fatal cases where applicable.[2][3]
• Provide, within five calendar days after DGE determines that a case is probable, the clinical record, laboratory and imaging results and a case presentation; report changes in status, hospitalisation or death immediately until final diagnosis.[3][5]
• Trace contacts and investigate shared exposures or links in time and place, while applying standard hospital precautions, personal protective equipment, hand hygiene, environmental cleaning and disinfection.[3][5]
• Avoid travel or trade restrictions solely because countries have reported cases.[5]

Governance spans the National Epidemiological Surveillance System, the National Committee for Epidemiological Surveillance, DGE, InDRE, state epidemiology services, LESP and participating health-sector institutions.[2][3]These institutions include the Ministry of Health, the Ministries of Defence and Navy, the Mexican Social Security Institute, the Institute for Social Security and Services for State Workers, Petróleos Mexicanos, the National System for Integral Family Development and the National Institute of Indigenous Peoples.[5]The National Epidemiological Surveillance Committee also recognises the contribution of surveillance units and network laboratories.[4]

Operational monitoring is based on suspected and probable case definitions, exclusion testing for hepatitis A to E, submission of the SUIVE-2 and REMU-F12 forms, laboratory documentation and ongoing federal review of new communications and publications.[2][3][5][4]As of 18 May 2022, ten probable cases had been notified nationally, including five in Mexico City, two in Nuevo León, and one each in Tamaulipas, Michoacán and Puebla.[2]A confirmed-case definition was not available at that time, and the source does not specify formal indicators, evaluation methods, financing arrangements, budgets or resource allocations.[3][4][7]

Monitoring & Evaluation

Monitoring and response are organised through Mexico’s National Epidemiological Surveillance System, linking first-, second- and third-level medical units, Hospital Epidemiological Surveillance Units, state epidemiology services, the National Committee for Epidemiological Surveillance, the General Directorate of Epidemiology and the National Public Health Laboratory Network.[1][2][3]The event concerns severe acute hepatitis of unknown cause in children and adolescents aged 16 years or under.[1][2]

• Apply a suspected-case definition for a person aged 16 years or under with acute hepatitis, markedly elevated aspartate aminotransferase or alanine aminotransferase above 500 IU/L, and no identified cause.[2]
• Classify a case as probable when testing for hepatitis A, B, C, D and E is negative through the National Institute of Epidemiological Diagnosis and Reference.[2][3]A confirmed-case definition was not available at the time covered.[3]
• Notify suspected cases through the SUIVE-2 Epidemiological Case Investigation Form, with public-sector units also informing their immediate institutional superior and private units reporting through the relevant sanitary jurisdiction.[2]
• Transmit case information from the state epidemiology area to the federal level, including laboratory results and a clinical summary.[2]Submit the REMU-F12 form, relevant laboratory studies and clinical documentation as required for surveillance follow-up.[2][3]
• Send clinical samples to the National Institute of Epidemiological Diagnosis and Reference through the National Network of Public Health Laboratories under refrigerated conditions and according to specified sample requirements.[2][3]Copy the state epidemiology area in the sample dispatch letter.[3]
• Provide the clinical record, laboratory and imaging findings, and a case presentation within five calendar days after the General Directorate of Epidemiology identifies a probable case.[3]Report changes in hospitalisation status or death immediately and continue notification until final diagnosis.[3][5]
• Review every probable case through an expert group and retain it under investigation until a final diagnosis is reached.[3]Support validation through the sanitary jurisdiction, state epidemiology services and laboratory acceptance criteria at the National Institute of Epidemiological Diagnosis and Reference.[2][3]
• Maintain conventional surveillance of viral hepatitis, investigate contacts and assess temporal and geographical associations between cases.[3][5]Follow the event and new related communications and publications through the Epidemiological and Health Intelligence Unit and the directorates responsible for surveillance of communicable and non-communicable diseases.[4]

International findings informed the surveillance alert. By 21 April 2022, at least 169 cases had been reported among children aged one month to 16 years in 12 countries, including one death.[1]Adenovirus was detected in 74 reported cases, type F41 in 18 cases with available typing information, and SARS-CoV-2 in 20 cases.[6]Clinical outcomes varied, with 10% of cases requiring liver transplantation at the time of reporting.[6]Thirty-three probable cases had been reported to the Pan American Health Organization from six countries in the Americas.[6]

Nationally, ten probable cases had been notified by 18 May 2022 at 20:00: five in Mexico City, two in Nuevo León, and one each in Tamaulipas, Michoacán and Puebla.[2]The source does not provide Mexico-specific performance indicators, targets, reporting-frequency metrics, evaluation methodology or a formal accountability framework beyond the notification, validation, laboratory review and expert-review mechanisms described.[6][2][3][4]

Costing & Financing

No costing or financial framework is provided for the surveillance and response activities. The material does not specify budgets, expenditure estimates, funding sources, resource allocations, resource-mobilisation arrangements, financing gaps or economic assumptions.[1][6][2][3][5][4][7]

• Undertake notification, laboratory testing, sample transport, case investigation, contact tracing, infection prevention and surveillance follow-up without any stated unit costs, programme costs or budget lines.[2][3][5]
• Use existing surveillance and laboratory institutions, including the General Directorate of Epidemiology, the National Institute of Epidemiological Diagnosis and Reference, state epidemiology services and the National Network of Public Health Laboratories, but without specified funding responsibilities or allocations.[2][3][4]
• Note that the source does not identify donor support, emergency financing, domestic funding mechanisms, procurement budgets, workforce financing or financial sustainability measures.[1][6][2][3][5][4][7]