dreyer

Modeling Lessons Learned from the SARS Outbreak: 

Modeling Lessons Learned from the SARS Outbreak Paul A. Dreyer Jr., Ph.D. Associate Mathematician RAND

Outline: 

Outline Brief Introduction to SARS Lessons Learned Quarantines Differing Control Measures Communication Hoaxes Conclusions

Introduction to Severe Acute Respiratory Syndrome (SARS): 

Introduction to Severe Acute Respiratory Syndrome (SARS) Symptoms Initially, high fever and chills, body aches After 2-7 days, dry coughing (along with possible oxygen depletion of blood) Incubation period up to 14 days Fatality rate about 10 percent (as of 4/25) Treatment CDC recommends treatment for pneumonia Still working on vaccine, determining vectors (transmission by ‘close contact’) SARS coronavirus identified, sequenced

Lessons Learned: Quarantines: 

Lessons Learned: Quarantines Quarantines seem to be effective, provided people actually quarantine themselves Individual refusals to quarantine in Toronto Concerns about stigmatization lead to concealment of illness Lack of notification to quarantine Taiwan: Personal attendants for inpatient care may have spread disease

“Ideal” Quarantine Method: 

“Ideal” Quarantine Method Healthy Person Contact w/SARS Infected Person Quarantine Until Contact + 10 Days Treatment and Notification Notification Of Possible Contact Symptoms? Symptoms? Yes Yes No No

“Realistic” Quarantine Issues: 

“Realistic” Quarantine Issues Healthy Person Contact w/SARS Infected Person Quarantine Until Contact + 10 Days Treatment and Notification Notification Of Possible Contact Symptoms? Symptoms? Yes Yes No No Problems: - Misdiagnosis - Non-reporting

“Realistic” Quarantine Issues: 

“Realistic” Quarantine Issues Healthy Person Contact w/SARS Infected Person Quarantine Until Contact + 10 Days Treatment and Notification Notification Of Possible Contact Symptoms? Symptoms? Yes Yes No No Problem: 100% coverage of all contacts difficult

“Realistic” Quarantine Issues: 

“Realistic” Quarantine Issues Healthy Person Contact w/SARS Infected Person Quarantine Until Contact + 10 Days Treatment and Notification Notification Of Possible Contact Symptoms? Symptoms? Yes Yes No No Problem: Refusal To Quarantine

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures United States No limitations on travel (travel advisories by CDC) CDC activated its Emergency Operations Center CDC recommends isolation of SARS-infected individuals Basic infection control procedures at hospitals CDC distributing health alert cards to passengers returning from travel in infected regions

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures Canada Hospital and school closings Checks at airport of incoming passengers Quarantines of health care workers

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures Singapore $10k fines and jail for breaking quarantine Illegal to mislead officials about travel history Health Ministry can: Quarantine any building Destroy any materials suspected to be sources of infection

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures Taiwan 10 day quarantines of all incoming passengers from SARS-infected areas (+ masks on flights) Widespread education of healthcare workers Full protective clothing for healthcare workers (including disposable 2nd layer of clothing) Active surveillance of exposed healthcare workers and contacts of patients (+ quarantines)

Lessons Learned: Differing Control Measures: 

Lessons Learned: Differing Control Measures Control measures vary from minor (US) to highly restrictive (Taiwan, Singapore, China) Differing control measures should be reflected in any modeling of global epidemics

Lessons Learned: Communication: 

Lessons Learned: Communication Communication methods are imperfect Not everyone receives notifications Not everyone believes the notifications However, new methods are developing Hong Kong hoax 6 million SMS messages sent to cell phones Location-based SARS updates via cell phone Real-time updated websites of SARS information SARS helpline also used for case detection

Lessons Learned: Hoaxes: 

Lessons Learned: Hoaxes Hong Kong hoaxes Los Angeles airplane scare Hoaxes (or misinformation) cause: misallocation of resources increased fear/confusion in populace possible health risks (smallpox)

Conclusions: 

Conclusions Epidemiological models should: Incorporate realistic quarantine models Acknowledge differing (and possibly conflicting) control systems across nations Consider imperfect information gathering as well as new communication methods