The Spread of SARS in Healthcare Settings: What Have We Learned? David J. Dausey, PhD RAND Corporation University of Pittsburgh

Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

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Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

Etiology New coronavirus isolated in Vero E6 cells from clinical specimens of 2 patients inThailand & Hong Kong with suspected SARS Isolate identified by electron microscopy, then immunostaining, indirect immunofluorescence antibody (IFA) assays, and reverse transcriptase-polymerase chain reaction (RT-PCR) with sequencing of a segment of the polymerase gene

Clinical Presentation Booth et al, 2003 Clinical features and short term outcomes of 144 patients with SARS in the Greater Toronto area. JAMA 289

Route of Transmission Spread from person to person through close contact Spread when an infected person coughs or sneezes shedding the virus from the respiratory track The virus is capable of surviving outside of the body on such surfaces for several hours No confirmed cases of SARS have been proven to occur through direct airborne transmission

Superspreaders Individuals who transmit the disease at a greater rate than other individuals CDC definition: a patient who transmits SARS to 10 or more people compared to the typical SARS patient who transmits the disease to less than half that number of people Superspreaders have a high viral load and cough a lot which may in part explain why they spread the disease at a greater rate than other infected individuals

Chest X-Rays Febrile prodome phase –Usually normal Respiratory phase –Early focal interstitial infiltrates –Progressing to more generalized, patchy, interstitial infiltrates –In late stages some show areas of consolidation. Advanced phase –Bilateral changes with interstitial infiltrations –Characteristic cloudy appearance.

Disease Progression Febrile prodome phase Respiratory phase Advanced phase Day 4: Normal Day 8: Minor opacities Day 14: Extensive opacities

Laboratory Features

Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

Origins A

Initial Spread METROPOLE Hotel Hong Kong 95 HCW >100 contacts United States 1 HCW 8 contacts Singapore 34 HCW 37 contacts Vietnam 37 HCW 21 contacts Canada 18 HCW 11 contacts B H,J F,G I, L,M C,D,E A K Ireland 0 HCW 0 contacts

Onset of Symptoms

Effect of disease Prevalence on Positive Predictive Value (PPV) Prevalence of SARS among persons tested PPV Sensitivity of detecting SARS in clinical specimen = 50% Specificity of test = 95% Prevalence = 1% PPV = 9% Prevalence = 50% PPV = 95%

Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

Total SARS Cases and % Healthcare Workers by Location Total No. SARS cases (bar) % HCW (line)

Canada SARS Spread

US Suspected SARS Spread

Was the US Better Prepared? Did advanced warning from other countries help the US? Did HCW take more precautionary measures when dealing with suspected SARS cases? Did active surveillance identify cases early allowing for early preventative action by HCW’s? Did HCW in US use isolation more than other countries? Did US HCW have more resources available to them that reduced the risks of transmission?

Was the US Just Lucky? Did the small number of cases reduce HCW risk? –One case in Prince of Whales Hospital in Hong Kong led to 60% of HCW at hospital becoming infected Were US cases less severely ill and thus less likely to spread the virus? –Phenomenon of superspreaders Did the relative absence of high-risk procedures in US reduce HCW risk? –Limited number of US patients were intubated, etc.

Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

Overarching Lessons We are now in a global community where diseases can spread from country to country very fast We are only as strong as our weakest link There needs to be open and honest dialogue between countries

Surveillance Lessons One missed case can lead to many new cases Early diagnosis and detection is crucial prevent further transmission Rapid contact tracing essential to disease containment

PPE Lessons Under certain circumstances SARS is not readily transmitted to close contacts despite ample unprotected exposures Using protective masks alone is not sufficient to eliminate SARS transmission among HCW Inconsistent use of protective garments is associated with HCW transmission

Communication Lessons Coordinating efforts with state and local health departments How, when and what to communicate Communicating with the media Avoiding public panic

Roadmap Brief overview of RAND Etiology and clinical features Epidemiology Nosocomial infections Lessons learned Preparing for future “SARS-like” outbreaks

Preparedness Train staff on the proper use of PPE Hospital surveillance systems Communication networks with public health Develop protocols and procedures for isolation Plan for surge issues

Surveillance and Reporting Providers State and local health departments CDC Community Health care facilities Screening

Role of Public Health Disseminate updated information and guidelines to providers Review potential cases reported by providers and evaluate for testing Identify and evaluate clusters Report cases to CDC immediately Conduct contact tracing

Thank You David Dausey x4408

Data Slides

HCW Infections in Hong Kong HCW outbreak occurred in 5 hospitals in the New Territories East Cluster of the Hong Kong Hospital Authority (n=77) –Alice Ho Miu Ling Nethersole Hospital (50%) –Prince of Whales Hospital (40.3%) –North District Hospital (2.8%) –Shatin Hospital (4.2%) –Taipo Hospital (2.8%)

Prince of Whales Hospital Prince of Whales Hospital was the site of the first large-scale outbreak among HCW’s –One patient infected 47 HCW –All HCW infected had close contact with patient while he was administered a bronchodilator through a jet nebulizer

Study by Lau et al (2004) 72 of 77 SARS infected HCW consented to participate in the study Study sample –59% nurses (n=43) –23.6% healthcare assistants (n=17) –9.7% medical officers (n=8) –2.8% clerical staff (n=2) –4.2% workmen (n=3)

Lau et al (2004) continued Nearly 100% of cases wore N95 mask or surgical mask In consistent use of goggles and gloves –44% of HCW reported inadequate supply of at least 1 item of personal protection equipment Only 50% reported received SARS infection control training –Those who were trained were significantly less likely to have been infected

Risk factors identified HCW performing high risk procedures on cases Having social contact with cases Staff experiencing minor problems with protective garments (e.g., shifting mask with hands) or not wearing garments Inadequate training

HCW Transmission in Singapore HCW outbreak occurred in 3 hospitals –Tan Tock Seng Hospital –Singapore General Hospital –National University Hospital A total of 206 cases and 31 deaths were reported

Tan Tock Seng Hospital Tan Tock Seng Hospital had 109 SARS cases-49 were HCW –8 Doctors –35 Nurses –3 Ancillary caregivers –3 others The hospital had 3 superspreading events Index case had multiple medical problems

Singapore General Hospital Singapore General Hospital had 60 SARS cases- 40 were HCW –3 Doctors –21 Nurses –6 Ancillary caregivers –10 Others Only had 1 superspreading event Index patient did not exhibit typical SARS symptoms

National University Hospital Had the smallest number of SARS cases-10 total only 3 were HCW Did not have a superspreading event Index patient was intubated and HCW involved in intubation became cases

Gopalakrishna et al (2004) Studied 92 HCW’s infected by SARS in Singapore’s 3 affected hospitals Initial SARS transmission came from nurses treating unknown SARS case One nurse treating case became superspreader infecting 25 other people

3 Containment strategies Each of the hospitals in Singapore tried different containment strategies –Closing ward, clinical area, or entire hospital Depends on how early outbreak was detected –Removing all potentially infected persons to a dedicated SARS hospital Depends on how likely infection cluster is identified –Managing exposed persons in place Depends on quick contact tracing

HCW Transmission in Canada Toronto had 144 SARS cases and 73 were HCW Infections occurred even in HCW that wore protective garments HCW in Toronto who had been exposed to SARS cases “voluntarily quarantined” themselves 3 hospitals closed during the outbreak

Loeb et al (2004) Studied SARS infections in critical care nurses in a Toronto hospital Found critical care nurses who assisted with suctioning before intubation and intubation itself were 4 times more likely to become infected than nurses without this exposure

HCW Transmission in Vietnam Hospital A-Privately owned hospital in Hanoi –HCW transmission closed hospital Hospital B-Expatriate-operated hospital in Hanoi –No HCW transmission

Vietnam: Hospital A HCW did not wear masks in earliest days after index case was admitted No infection control procedures were taken until nosocomial cluster was identified HCW had longer and closer contact with cases in Hospital A than B Hospital had superspreading event

Vietnam: Hospital B Had a total of 33 confirmed SARS cases No superspreader events No cases died or required mechanical ventilation 100% of HCW work protective masks

HCW Transmission in US Park et al (2004) identified 110 US HCW with exposure within droplet range (i.e., 3 feet) of 6 (out of 8 total) confirmed SARS patients. –45 had exposure without wearing mask –49 had exposure without N45 or higher respirator –72 had exposure without eye protection –40 reported direct contact without gloves