Containment and Control WHO Pandemic Phases Phase Period Level of - PDF document

Containment and Control

WHO Pandemic Phases Phase Period Level of Risk 1 Interpandemic period Low risk of human cases 2 New virus in animals, Higher risk of human cases no human cases 3 Pandemic alert No or very limited human-to- human transmission 4 New virus causes Evidence of increased human- human cases to-human transmission 5 New virus causes Evidence of significant human- human cases to-human transmission 6 Pandemic Efficient and sustained human- to-human transmission

Overview of NPI Individual level Community level • Isolation • Cordon sanitaire • Quarantine • Social distancing • Infection control practices • Personal protective equipment

Individual Level NPI

Isolation • Isolate severe and mild cases • Do not wait for lab confirmation • Isolation location depends on several factors • Provide medical and social care

Quarantine • Reduces likelihood of virus transmission • Quarantine all case contacts – Necessary even if cases are undergoing antiviral prophylaxis • Voluntary quarantine preferable – Educate the public – Authorities should prepare to enforce quarantine • Provide medical and social care

Principles of Modern Quarantine • Works best when obtain and maintain public trust • Use the least restrictive measures • If persons in quarantine become sick, isolate (separate) them from healthy persons • Provide essential services and medical care; address financial, mental health, stigma, workforce depletion, legal, human rights issues

Quarantine Determine who to quarantine: • Identify case contacts during medical exam • Conduct contact tracing During quarantine: • Actively monitor contacts for development of symptoms • Implement self-health monitoring

Infection Control Practices and Personal Protective Equipment • Hand washing • Cough etiquette • Disinfecting surfaces • Masks and other PPE

Masks • SARS, in some areas, required for – travel on subway – taxi drivers – inside hospitals

Community Level Interventions Social Distancing Measures

Quarantine of Groups or Sites • Use when there is evidence or suspicion of human-to-human transmission • Actively monitor household members for illness • Provide medical care

Quarantine of Groups or Sites Cordon sanitaire • Prevents ill, exposed persons from mixing with society • Barrier restricts travel in and out of an area • Helpful in closed settings • Impractical in some settings – Not recommended by WHO

Cordon sanitaire Challenges • Site selection • Monitoring for illness • Logistics • Providing medical care • Provision of basic needs • Communication

Movement Restrictions • Possible measures: – Restricting public transportation – Restricting public gatherings – Voluntary or involuntary work holidays • Logistical considerations: – Effectiveness – Implementation – Alternative transportation infrastructure

Cancellation of Events • Practice based on observations during the 1957 – 1958 influenza pandemic • In response to a presumed AI cluster – Likely to contribute to successful pandemic containment • In response to an established pandemic – Consider impact on economy – Consider cultural significance of events

Closure of Facilities • Schools – Practice based on observations during the 1957 – 1958 influenza pandemic – Useful if high morbidity, mortality among children – Most effective early in an outbreak • Businesses and markets – Consider access to and availability of necessities – Consider economic impact

Study of Containment of Emerging Virus in Rural Thailand • Antivirals to 90% of people in 5 km radius within 2 days after detection of 20 cases was estimated to contain a new influenza subtype • If also close 90% of schools, 50% workplaces; 80% reduction in movement in and out of area, � 90% chance of containment of new subtype • Containment predicted if <200 cases; or at least delay spread by a month or more Source: Ferguson et al. Nature 2005;437:209-14

Study of Containment of Emerging Virus in Rural Thailand • If no antivirals given, and • If every case stayed at home, and • 70% of susceptible people did not travel out of their neighborhood, • Probability of containment: – 98% if Ro=1.4 – 57% if Ro= 1.7 Source: Longini et al. Science 2005;309:1083-7

International and National Containment Measures

Health Alert Notices • Health advice for travelers • Risks, precautions, defer travel to affected areas • Symptoms, early self-isolation • Seek medical care (call ahead), lab diagnosis • Notify public health authorities References: WHO Global Influenza Plan, 2005; WHO Writing Group. Emerg Inf Dis 2006;12:81-7

Screening • EXIT screening for travelers from affected countries • Entry screening considered only exceptionally – Infection-free isolated areas (islands) – If exit screening not done in affected countries – If limited internal surveillance capacity

Screening: International Travelers • Entry screening / quarantine was ineffective in 1918, except in some island countries – In Australia, delayed introduction for 3 months • Likely even less effective today (air travel) – Not cost-effective during SARS

Thermal Scanning • Displays a thermal image of pedestrians • Can be used to detect body temperature above a set threshold – e.g. 37° C • Used to screen and identify persons requiring further assessment by medical personnel

Thermal Scanning at International Borders (2003) Area # scanned # febrile by # SARS (millions) scan(confirme found by d by oral) scanning Canada 0.6 248 (215) 0 China-mainland 13.0 4070 (351) 0 China-Hong Kong 15.1 NA (451) 0 SAR* China-Taiwan 1.0 1211 (0) 0 Singapore 6.0 5200 (3160) 0 TOTAL 35.7 10729 (4177) 0 Source: Bell D Emerging Inf Dis J 2004:10:1900 *includes border with China-mainland

National Measures 1. Ill persons should voluntarily stay at home (at the first sign of symptoms) 2. If pandemic is severe, measures to “increase social distance” should be considered 3. “Non-essential domestic travel to affected areas should be deferred if many areas of a country remain unaffected” • Prohibition on travel from affected areas is usually impractical References: WHO Global Influenza Plan, 2005; WHO Writing Group. Emerg Inf Dis 2006;12:88-94

Country Responsibilities • Implementation and maintenance of quarantine area and all public health measures • Distribution and administration of antiviral drugs • Monitoring the well-being and physical needs in quarantine zone • Conducting surveillance of surrounding areas to detect cases Source: WHO pandemic influenza draft protocol for rapid response and containment

Pharmaceutical Interventions Triggers for Non-

Contextual Factors • Shift in the pandemic phase • Local public health and emergency infrastructure • Community understanding

Outbreak-Specific Factors • Geographic extent • Number of cases – Area small enough that – Moderate to severe containment would be illness in 3 or more logistically possible health care workers – Can supply food, shelter, medical care to affected – Moderate to severe area illness in 5 to 10 people with some evidence of human-to-human • Pandemic potential transmission – Presence of clusters in defined area over short period of time – Pattern of unexplained respiratory illness

WHO Recommendations for NPI Implementation Phase 3 Phase 4 & 5 Phase 6 (Current) (Rapid (Pandemic) response) Isolation Yes Yes Yes Quarantine No Yes Possibly Identification of contacts Yes Yes No and health monitoring Cordon sanitaire No Possibly No Facility closure, movement Possibly Yes Possibly restrictions, cancellation of events

Implementation of NPI

Coordination Non-governmental Organizations (NGOs): • Help governments disseminate health messages • Get community buy-in for interventions • Assist directly with health monitoring, supplies, medical care

Concurrent Measures Combining measures reduces spread of infection more than using only one measure

Security • Collaborative effort of health officials, local police, and military • Social distancing measures may require security considerations

Logistics • Medical care – Ensure health care providers are available – Train and inform health care providers – Have contingency plans for provider absence • Self-health monitoring – Distribute ‘signs and symptoms’ information to the population – Establish hotlines to answer questions about signs and symptoms

Risk Communication • Designate one source for official information • Deliver clear, consistent messages • Target the majority of the population • Abate or counter incorrect information

Psychological and Social Impact • Impact on the public: – Anxiety – Depression • Measures to lessen impact: – Explain why NPI measures are necessary – Provide updates on when ban will be lifted – Staff hotlines to answer questions