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Wkly Epidemiol Rec. Severe atypical pneumonia outbreak associated with influenza A(H1N1)pdm09 in Egypt, 2013?2014 season

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  • Wkly Epidemiol Rec. Severe atypical pneumonia outbreak associated with influenza A(H1N1)pdm09 in Egypt, 2013?2014 season

    [Source: World Health Organization, Weekly Epidemiological Record, full PDF document: (LINK). Edited.]

    Weekly epidemiological record / Relev? ?pid?miologique hebdomadaire - 18 APRIL 2014, 89th year / 18 AVRIL 2014, 89e ann?e, No. 16, 2014, 89, 161?164 /

    Severe atypical pneumonia outbreak associated with influenza A(H1N1)pdm09 in Egypt, 2013?2014 season

    During the period December 2013 ? January 2014, an unusual increase in cases of atypical pneumonia was reported from Dakahlia Governorate in Egypt, situated north of Cairo in the Nile Delta, with a population of approximately 5 million.

    The number of cases almost doubled that in the same time period in 2012?2013. In response to the outbreak, an investigation was conducted by the Ministry of Health and Population (MoHP).

    Of 24 cases reported to the MoHP between 1 December 2013 and 17 January 2014, 13 cases (54%) were found to be positive for influenza A(H1N1)pdm09.

    By 26 January 2014, the total number of laboratory-confirmed cases reported to the MoHP had increased to 75.

    Five deaths among health-care workers (HCWs) were also widely reported in the media, suggesting that nosocomial transmission may have contributed to a sudden, rapid spread of infection.

    Due to an unusually large number of severe cases resulting in hospital admission and/or death, the MoHP requested assistance from WHO on 5 February 2014.

    A WHO team of technical experts was deployed to Egypt on 9 February 2014 to support the country office and investigate the outbreak, providing technical assistance in the areas of clinical management, infection prevention and control (IPC), epidemiology and surveillance, and communications.

    The team visited Abbasia Chest Hospital in Cairo which also reported increasing numbers of severe pneumonia cases, Dakahlia Chest Hospital, and Dakalia University Hospital in Mansoura, the capital of Dakahlia Governorate, to interview health-care workers and observe clinical management of patients.

    The team also visited the Central Public Health Laboratory (CPHL) and the U.S. Naval Medical Research Unit (NAMRU) to obtain information related to laboratory capacity, testing procedures, and most recent laboratory data.

    In collaboration with the MoHP, WHO reviewed recent data on the clinical disease course among severely ill patients with confirmed Influenza A(H1N1)pdm09 infection, finding a median of 2 days from hospital admission to intensive care unit admission, at which stage patients with severe respiratory disease and acute respiratory distress syndrome required ventilatory support.

    It was found that referral of patients to tertiary health care was frequently delayed.

    Upon the reception of laboratory test results indicating influenza A(H1N1) pdm09 being responsible for the increase of severe pneumonia cases, concomitant empiric antimicrobial treatment for community acquired pneumonia with influenza antiviral medication was provided to patients with undifferentiated severe acute respiratory infection (SARI), and those with suspected post-influenza bacterial pneumonia.

    The MoHP, in response to the Supreme Court?s advice, distributed the antiviral medicine (i.e. oseltamivir) to a more peripheral level which resulted in reduction of overall mortality.

    Over time, increasing media coverage of the outbreak probably led to increased awareness among the general population and health-care providers, and possibly also resulted in earlier detection, diagnosis and treatment.

    Evaluation of the national IPC programme and IPC teams in the hospitals visited by the WHO team revealed that IPC resources and supplies, including gloves and gowns, were available to HCWs.

    Compliance with standard precautions varied between the hospitals, and additional precautions, specifically concerning droplets, were implemented consistently. There was no evidence that health care-associated transmission contributed to the increased number of cases.

    The CPHL and NAMRU are the 2 major laboratories which receive and test all samples collected at Egypt?s sentinel surveillance sites from cases that meet the 2011 WHO case definition for SARI.

    Since the start of the outbreak, these laboratories also tested samples from hospitals and other health-care facilities which are not part of the routine surveillance system.

    Samples were tested for Middle Eastern respiratory syndrome coronavirus (MERS-CoV) and 22 other pathogens including influenza, using polymerase chain reaction.

    Of >2200 samples tested, influenza A(H1N1)pdm09 accounted for 60% of all influenza viruses detected this season and 70% of all influenza A viruses.

    It was also found that influenza A(H1N1)pdm09 virus was sensitive to oseltamivir, and genetic sequence data demonstrated no notable mutations from previous years.

    These results must be interpreted with caution as the quality of many samples was inadequate for testing and analysis.

    Surveillance data coupled with the clinical disease characteristics showed that the epidemiology of influenza A(H1N1)pdm09 in 2013?14 resembled that in 2009?2010.

    Infection was most common among the relatively young (median age 47 years).

    Among 44 deceased patients with laboratory confirmation, 75% were aged 25?54 years; 75% had a pre-existing medical condition, including pregnancy (16%), diabetes mellitus (14%), cardiac disease (11%), and chronic respiratory disease (11%).

    The influenza and respiratory disease surveillance system in Egypt has both a sentinel component which provides baseline and trend data, and an early warning component for unusual events.

    Yet, there is a need to strengthen early warning function and to improve data analysis and feedback at the subnational levels as the consolidated national data were not indicating unusual influenza-like illness and SARI activities during this period.

    Based on these clinical, epidemiological, and virological data, the WHO team concluded that Egypt had an unusually severe influenza season, primarily associated with influenza A(H1N1)pdm09.

    The virus has been circulating since its emergence in 2009, having periodic severe health impacts in different parts of the world.

    During the 2012?2013 season, the virus was widespread and causing SARI with the typical pandemic (H1N1) 2009 epidemiological characteristics in Iraq, Jordan, Tunisia and Yemen, and also in the West Bank and Gaza Strip.

    WHO deployed its antiviral stockpile in response to requests from the affected areas and countries.

    This outbreak investigation yielded several notable lessons and revealed the need for WHO recommendations for monitoring and controlling influenza outbreaks in resource-constrained settings:
    • (i) Of the large numbers of samples collected from patients with SARI, the great majority of those submitted to CPHL and NAMRU were naso-pharyngeal swabs. The importance of obtaining lower respiratory tract (LRT) specimens for the diagnosis of SARI has been increasingly stressed in scientific literature, suggesting upper respiratory tract specimens are inadequate, especially for severe influenza virus and MERS-CoV infection; however, such specimens were rarely collected. In areas without equipment or capability to safely perform certain LRT sampling procedures, ?induced sputum?? is a potential alternative, which is commonly used for tuberculosis testing.
    • (ii) The samples collected were often of suboptimal quality. Successful laboratory diagnosis relies on sample quality, and it is important to obtain specimens using appropriate collection methods and transport them to the laboratory in good condition in a timely fashion. Recognizing the presence of MERS-CoV and avian influenza A(H5N1) virus in the region, there is an urgent need to raise awareness of clinicians on LRT specimen collection, training and equipment, to promote early and accurate laboratory diagnosis.
    • (iii) The vulnerability of pregnant women to influenza A(H1N1)pdm09 was confirmed this season in Egypt, as has been observed in earlier epidemic waves elsewhere, supporting the recommendation made by the WHO Strategic Advisory Group of Experts on immunization concerning pregnant women; as a direct result a targeted vaccination strategy is being discussed for this at-risk group. However, a large annual demand for seasonal vaccine to cover an estimated 2 million pregnancies poses challenges for countries with competing health priorities.
    • (iv) In accordance with WHO clinical management guidance, provision of both empiric antiviral treatment and concomitant empiric antimicrobial treatment to patients with undifferentiated severe acute respiratory infection, pending further test results, is recommended when community circulation of the virus is known.
    • (v) It is important to establish a communication channel and strategy to connect clinicians, laboratories, and public health officials in order to enhance appreciation of influenza activity and clinical diagnostic suspicion, a rapidly shifting balance of capacity and demand in the health-care system, and facilitate evidence-based clinical decision-making.
    • (vi) Effective communication in the delivery of public health messages is a powerful tool in facilitating control and prevention efforts.

    Severe influenza infection also highlights the need for strong capacity for clinical care of patients with respiratory failure.

    During this outbreak WHO provided an in-country training course for HCWs in affected areas on several aspects of clinical care.

    This included specimen collection and sampling, specifically from the lower respiratory tract, such as tracheal aspirates, induced sputum, and broncho-alveolar lavage. In addition, the training course provided instruction on severe influenza and undifferentiated SARI case management.

    WHO will continue to provide technical advice and assistance in enhancing the surveillance system and laboratory capacity, generating public health and clinical management recommendations for critical care, revising the national IPC guidance, and supporting riskcommunication training activities.