Tài liệu Influenza A (H5N1): Prevention pptx

Influenza A H5N1: Prevention Prof.. “If the pandemic were to start now, we would have to rely on non-vaccine measures for atleast 6 months.... Vaccines may only be available for the se

Influenza A (H5N1):

Prevention

Prof Nguyen Duc Hien, MD, PhD

Director of NIITD, Vietnam

• Prevention of Infectious diseases

– Measures

• Vaccines/antiserum

• Standard/universal precautions

• Personal protective equipments

• Prophylatic medications

• Quarantine and isolation

• Prevention of Infectious diseases

– Levels

• In hospital

• Close contacts

• Community

• Pandemics

• 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 ≤ 7 days before illness onset – Having sick/dead poultry in the household ≤ 7 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

non-vaccine measures for atleast 6

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

do 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

• 7 days ?

• As long as 7 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 1 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 7 (or 14 ?) days after the last exposure:

– Close contacts

– Heathcare workers

• Who have a fever > 38 0 C 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 7 days

– Children: for 21 days

THANK YOU FOR YOUR ATTENTION