Tài liệu Influenza A (H5N1): Prevention pptx

Influenza A (H5N1): Prevention Prof Nguyen Duc Hien, MD, PhD Director of NIITD, Vietnam Introduction • Prevention of Infectious diseases – Measures • • • • • Vaccines/antiserum Standard/universal precautions Personal protective equipments Prophylatic medications Quarantine and isolation Introduction • Prevention of Infectious diseases – Levels • • • • In hospital Close contacts Community Pandemics Introduction • Prevention of Infectious diseases – Functions of: • Healthcare workers – Clinicians – Grassroot healthcare workers • Epidemiologists • Household members • Policy makers Influenza A (H5N1) • Etiology: virus – Effectiveness of antivirals • Oseltamivir, zanamivir • Amantadine (?), Rimantadine (?) • Transmission – Route • Respiratory tract • Gastrointestinal tract – Methods • Droplets • Airborne (?) Influenza A (H5N1) • Risk factors – A match case-control study from NIHE 2006 • Design – 28 case-patients – 106 control-respondents • Results – Preparing sick/dead poultry ≤ days before illness onset – Having sick/dead poultry in the household ≤ days before illness onset – Lack of an indoor water source – No clear evidence of human-human transmission Control Influenza A (H5N1) • Prerequisite – Control avian influenza in poultry • • • • • Vaccines Early detecting poultry cases Localizing outbreak areas Destroying suspected poultry flocks Future: centralization in raising/slautering – Control poultry-human contacts • Propagation/Health education – Symptomatic surveillance • Prophylaxis for poultry workers and household members (?) – Oseltamivir 75 mg qd Prevention: Vaccines • H5N1 vaccine: in studying • Yearly vaccine production – Antigen: H1N1, H3N2 and influenza B • Influenza antigen: shift and drift – Require yearly data from global influenza surveillance – Rate of vaccine failure ? • Type of Influenza vaccine – Killed vaccines – Live vaccines Prevention: Vaccines • Recomendation – Groups to target FLU-A • • • • • Facilities Likelihood of transmission to high risk persons Underlying medical conditions Age > 65 years/6-23 months Poultry workers ??? – Guidelines from WHO, CDC – Priority in pandemic situation ? “If the pandemic were to start now, we would have to rely on nonvaccine measures for atleast months Vaccines may only be available for the second wave of the pandemic Starting preparation now is essential” “Our goal should be to develop a new cell culture-based vaccine that includes antigens that are present in all subtypes of influenza virus that not change from year to year, and that can be made available to the entire world population” (Osterholm, NEJM 2005) Prevention: Standard/Universal precautions • Simple but important measures • Must be applied to all patients receiving care in hospitals • Require strengthening education for healthcare workers • Developping countries: – Health education for patients’ ralatives Prevention: personal protective equipment • High-efficiency mask – European CE approved respirators – US NIOSH certified N-95 • Gown • Face shield/google • Gloves Prevention: prophylactic medications • Medication – Oseltamivir 75 mg qd • In hospital – Close contacts without protective equipments • Patient’s ralatives • Healthcare workers • Community – Poultry workers contact with H5N1 poultry – Household members of H5N1 cases Prevention: prophylactic medications • Shortcoming issues – Stockpile: • How many courses and for how long • Strategies for drug turning over – Duration of prophylactic treatment • days ? • As long as days after last contacts ? – Side effects ? – In outbreak areas • Oseltamivir must be given all population in the area that have the first human H5N1 cases ? Prevention: quarantine and isolation • Manage suspected cases in seperated room – Negative pressure room – Waste disposal inside – Each room has a buffer room • Patient beds – More than m apart – Seperated by a physical barrier Prevention: quarantine and isolation • Limit the number of – Healthcare workers who have direct contact with the patients • They should not look after other patients – Other hospital employees with access to the environment of these patients • Cleaners • Laboratory personnel – Visitors • Provide them with appropriate personal protective equipment and instruct them in its use Prevention: quarantine and isolation • Monitor body temperature and other symptoms for (or 14 ?) days after the last exposure: – Close contacts – Heathcare workers • Who have a fever > 380C and who have had direct patient contact should be treated immediately • All preventive measures for patients remain in place after resolution of the fever – Adults: for days – Children: for 21 days THANK YOU FOR YOUR ATTENTION ... B • Influenza antigen: shift and drift – Require yearly data from global influenza surveillance – Rate of vaccine failure ? • Type of Influenza vaccine – Killed vaccines – Live vaccines Prevention: ... last contacts ? – Side effects ? – In outbreak areas • Oseltamivir must be given all population in the area that have the first human H5N1 cases ? Prevention: quarantine and isolation • Manage suspected... suspected cases in seperated room – Negative pressure room – Waste disposal inside – Each room has a buffer room • Patient beds – More than m apart – Seperated by a physical barrier Prevention: quarantine