Infectious diseases

and health care

workers

David Koh

Assistant Vice Chancellor and

Vice-President (Research & Innovation)

Distinguished Professor of

Occupational Health & Medicine

david.koh@ubd.edu.bn

1st National Conference on

Occupational Health in Healthcare October 30‐31, 2015, Christian Medical College, Vellore

Land Area –

5765 sq km

Population

(2013) –

415,717

GDP (2012) –

21.9 billion per capita

US$50,440

Ebola virus - first identified in Africa, 1976-2013 - >20 outbreaks, 200 cases

West Africa, 2013 – 2015 Aug - >28,000 cases, >11,000 deaths

HCWs – 20-30X more likely to be infected, 2/3 of those infected died

Risk of occupationally acquired infections among healthcare workers

(HCWs) is well recognized e.g. TB, hepatitis, scabies, SARS, AI, MERS

Picture Source: The Guardian

Probable cases of SARS worldwide, 7 August 2003. Source: WHO

Cumulative Total : 8,422 cases and 916 deaths, reported from 29 countries

Group 1 Coronaviridae

Canine, feline infectious peritonitis

Porcine transmissible gastroenteritis

Porcine respiratory virus

Human - HCoV 229E

Group 2 Coronaviridae

Bovine, murine hepatitis

Rat sialodacroadenitis virus

Human - HCoV-OC43

Group 3

Coronaviridae (Avian)

Avian infectious bronchitis

Turkey coronavirus

HCoV – NL63

(affects mainly children)

SARS Co-V

Coronaviridae Groups

van der Hoek L, Pyrc K, Jebbink MF, Vermeulen-Oost W,

Berkhout RJ, Wolthers KC, Wertheim-van Dillen PM,

Kaandorp J, Spaargaren J, Berkhout B. Identification of a

new human coronavirus. Nat Med. 2004 Apr;10(4):368-73.

Large, enveloped, positive sense single stranded RNA viruses

Can survive on environmental surfaces for up to 3 hours

Mode of Transmission

* Direct mucous membrane

contact with infectious

respiratory droplets

* Exposure to fomites

* ? Faecal

(73% of Amoy Gardens

cases had diarrhoea)

Yu IT et al. Evidence of airborne transmission of the severe acute

respiratory syndrome virus. N Engl J Med. 2004 Apr 22;350(17):1731-9.

Computational fluid-dynamics modeling

of the Movement of the Virus-Laden Plume

SARS

Incubation period

2 – 6 days

(1 - 14 days)

Case fatality rate

Overall : 11 %

Range : 0 to 50%

(depending on age,

co-morbidities)

Lesson - #1

Health care work can be

hazardous to health !

• 21 % of SARS patients were HCWs

Range: 3% in the USA, to 43% in Canada

(In Singapore, the rate was 41%)

• Differential risk for different types of HCWs

• All HCWs (including traditional healers)

are potentially at risk

• Even apparently low exposure

situations can pose a risk

D Koh, Lim MK, Chia SE.

SARS: health care work can be hazardous to health.

Occupational Medicine, 2003; 53 (4): 241-3.

Health care work can be hazardous

Attack Rate for Health Care Workers in

the Hanoi French Hospital

Overall Attack Rate – 18%

Doctor – 16%

Nurse – 35%

Administrative staff – 2%

Other staff with patient contact – 53%

Patients admitted for other reasons - 7%

Source: WHO, 17 Oct 2003

Attack Rates among HCWs in Hong Kong

339 SARS infected HCWs in 14 of 16 Hospital Authority hospitals that

managed SARS cases

Staff Category Attack Rate Range

Nurses 1.21 % 0 – 4.7 %

Medical / Technical 0.29 % 0 – 1.5 %

* Non-medical support 2.73 % 0 – 13.3 %

Overall 1.2 %

Lau JTF, Yang X, Leung P-C, Chan L, Wong E, Fong C, et al. SARS in three categories of hospital

workers, Hong Kong. Emerg Infect Dis [serial on the Internet]. 2004 Aug [date cited]. Available from:

http://www.cdc.gov/ncidod/EID/vol10no8/04-0041.htm

* Healthcare assistants, cleaners, clerical staff

High risk procedures

- Intubation, suction

- Nebulized aerosol therapy

- Positive pressure non-invasive

ventilation

Proximity is Important Attack Rate of Medical Students, Prince of Wales Hospital

100% - for those who visited patients in beds

adjacent to an index case ( 3 / 3 )

50% - for those who entered the same cubicle

as an index case ( 4 / 8 )

0% - for those who had only entered the

same ward ( 0 / 8 )

Wong T-W, Lee C-K, Tam W, Lau JT-F, Yu

T-S, Lui S-F, et al. Cluster of SARS

among medical students exposed to

single patient, Hong Kong. Emerg Infect

Dis [serial online] 2004 Feb [date cited].

Available from: URL:

http://www.cdc.gov/ncidod/EID/vol10no2/

03-0452.htm

The Inanimate Environment Can Facilitate Transmission

~ Contaminated surfaces increase cross-transmission ~

Abstract: The Risk of Hand and Glove Contamination after Contact with a VRE (+)

Patient Environment. Hayden M, ICAAC, 2001, Chicago, IL.

X represents VRE culture positive sites

Other Hospital

In-patients

Other Health

Care Workers

OTHERS

AT RISK

Lesson - # 2

The effect of SARS

extends beyond the

infection

The impact of SARS extends

beyond the infection

* Psychological effects High degree of distress experienced by

29 % - 35 % of hospital workers

* Overwork and job demands

* Social effects

* Effects on the family

Maunder R. The experience of the 2003 SARS outbreak as a traumatic

stress among frontline healthcare workers in Toronto: lessons learnt.

Phil Trans R Soc Lond 2004; 359(1447): 1117-25.

SARS among Singapore HCWs

To study work & non-work related problems

among HCWs in Singapore

Study Design

Questionnaire survey of

15,025 health care workers

in 9 health care settings,

from May-July 2003

D Koh, MK Lim, SE Chia, SM Ko, F Qian, V Ng, BH Tan, KS Wong, WM Chew, HK Tang, W Ng, Z

Muttakin, S Emmanuel, NP Fong, G Koh, CT Kwa, KBC Tan, C Fones. Risk perception and impact of

Severe Acute Respiratory Syndrome (SARS) on work and personal lives of healthcare workers in

Singapore: what can we learn ? Med Care. 2005 Jul;43(7):676-82.

Impact on Family and Social life

82% were concerned about

passing SARS to family

members, close friends,

or work colleagues

87% agreed that “people close

to me are worried for my health”

69% felt that “people close to

me are worried they might get

infected through me”

Impact on Family and Social life

Negative

49% thought that “People

avoid me because of my job”

31% felt that “people avoid my

family members because of my job”

Positive

82% of respondents felt

“appreciated by the

hospital / clinic / my employer”

77% felt “appreciated by society”

Lesson - # 3

General principles for

prevention and control

are effective for SARS

Containment

* Isolate SARS

suspected patients

* Quarantine

- those with

exposure to SARS cases

* Limit social interactions to

prevent inadvertent SARS

exposures

Secondary cases of SARS by days to isolation of the

source case. Singapore, reported to 15 April, 2003

Strict Adherence

Airborne Precautions

- use of N95 masks

Contact and Droplet Precautions

- hand hygiene, gloves

- gowns

- eye protection

Risk in the transmission of SARS-CoV

reduced by adherence to PPE

Intervention SARS Co-V infected % Uninfected % p value

n = 127 n = 331

N95 mask 85.8 99.4 <0.001

Hand washing 90.6 97.2 0.004

N95 mask + gloves 40.0 81.0 < 0.001

+ gown + hand washing

Adapted from: Seto WH. SARS Nosocomial infection and infection control. SARS

clinical management workshop, 13-14 June 2003. China, Hong Kong SAR.

PPE Program

Fit testing

Training on wearing and removal of PPE

Disposal, cleaning, decontamination

Enhanced respiratory protection e.g.

Powered Air Purifying Respirators (PAPRs)

ehs.unc.edu/training/self_study/ n95/11.shtml

The Straits Times April 17 2003

A discarded surgical mask lies

on the sidewalk outside SARS

clinic setup of Sunnybrook &

Women's hospital in Toronto,

Canada.(AFP/File/J.P. Moczulski)

Other Preventive Measures

• Tracking of patient and staff movements

• Restriction of movements of patients within and

between institutions

• Restriction of staff movts within and between facilities

• Temperature Monitoring

of Health Care Workers

• Contingency planning

• Quarantine

Lesson - # 4

Impact on occupational

health practitioners

- SARS requires an

OH response

SARS – a newly emergent

occupational disease

* Health care workers

* Animal and food

preparation handlers

* Transport workers

- flight attendants,

taxi drivers

* Laboratory Researchers

Early cases of SARS

More than 1/3 of cases with dates of onset

before 1 Feb. 2003 were persons who

handled, killed or sold food animals, or

those who prepare or serve food WHO Consensus document on the epidemiology of severe acute respiratory syndrome

(SARS). 17 October 2003. http://www.who.int/csr/sars/en/WHOconsensus.pdf

Airline Transmission of SARS

Flights with symptomatic probable cases,

23 February-23 May 2003

Lim MK, D Koh. SARS and occupational health in the air.

Occup Environ Med 2003; 60: 539-40.

Source: WHO Airline transmission of SARS database, 2003.

MMWR May 9, 2003. 52(18) 405-411.

Two taxi drivers who transported a SARS patient to and

from a vegetable stall (on 5 & 8 Apr) were infected

Occupational Health Consultations

• Stock exchange

• Transport workers union

• Sewage workers

• Multinational companies

• Health care facilities

An occupational disease requires an

occupational health response

* Occupational health response - industrial hygiene, audits

- education, PPE, compliance

- mental health support

- outbreak ix, sickness absence

- business continuity

* Designation as “Occupational disease” - workers’ compensation

- employer responsibility

March 12, 2003

The WHO issued a global health alert stating that ”a new,

unrecognizable, flu-like disease may spread to health-care workers”

Lesson - # 5

SARS and other emerging

occupational infectious

diseases will continue to

pose threats to HCWs

Most likely scenarios :

1 Original or new

animal reservoir

2 Undetected transmission

in humans (? Seasonal)

3 Persistent infection in humans

4 Laboratory accidents

Will SARS Re-emerge ?

Laboratory Acquired Infections

Lab Accident # 1 - Singapore Sep 2003

27 year old postdoctoral student

23 Aug – 30 minutes at lab working on West Nile virus

26 August – Developed fever at midnight, later tested SARS +ve

Lab Accident # 2 - Taiwan Dec 2003

44 year old military researcher, at the Institute of Preventive

Medicine of the National Defense Medical Centre

# 1. Lim PL et al.

Laboratory-acquired severe acute respiratory syndrome.

N Engl J Med. 2004 Apr 22;350(17):1740-5.

# 2. Normile D.

Second Lab accident fuels fears about SARS.

Science 2004. Jan 2004, 303: 26.

Impact of SARS on the HCWs

* SARS - a grim reminder that

health care work can be

hazardous to health

* Its effect extends beyond the

infection

* General principles for prevention

and control are effective

* An Occupational Health response

is required

Emerging occupational infectious

diseases will continue to pose

threats to HCWs

SARS (or something else) will be back

- remain ever vigilant

- prepare for the

next outbreak

DK in

April

2003

2005 – Bird flu

2009 – Swine flu

2012 – Camel flu

2014 – Ebola

2015 - MERS

? 2016

We need to be better prepared

Thank You

david.koh@ubd.edu.bn

In a HK-Beijing flight with a SARS patient in the symptomatic period of the

disease and 119 other persons, SARS was transmitted to 16 persons, 2

others were given diagnoses of probable SARS, and 4 were reported to

have SARS but could not be interviewed

Olsen SJ, Chang HL, Cheung TY, Tang AF, Fisk TL, Ooi SP, Kuo HW, Jiang DD, Chen KT, Lando J, Hsu

KH, Chen TJ, Dowell SF. Transmission of the severe acute respiratory syndrome on aircraft. N

Engl J Med. 2003 Dec 18;349(25):2416-22.

Superspreaders

* Increased viral shedding,

due to

? advanced disease

? co-morbidities

* Other transmission routes

* Inadequate infection control

measures

1 32 y/o male TV producer

(rats in apartment)

2 20 y/o restaurant waitress

3, 4 35 y/o businessman,

40 y/o hospital medical

director/physician Diners at restaurants (next door to, and at the restaurant where #2 worked)

Guangdong, China

Dec 2003 – Jan 2004

FANG Ling et al. A serologic diagnosis and study on SARS antibody of newly occurred 4 confirmed

SARS cases in 2003-2004 in Guangdong, PR China. International Conference on SARS One Year After

the (first) Outbreak Musik- und Kongresshalle – Lübeck, Germany, May 8-11, 2004.

Liang G, Chen Q, Xu J, Liu Y, Lim W, Peiris JSM, et al. Laboratory diagnosis of four recent, sporadic

cases of community-acquired SARS, Guangdong Province, China. Emerg Infect Dis [serial on the

Internet]. 2004 Oct [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol10no10/04-0445.htm

Beijing, April 2004

* 2 laboratory workers at the CDC’s

Institute of Virus Diseases

* Health care worker

* Family contacts

9 cases in all

1 death Normile D. Severe acute respiratory syndrome: lab accidents prompt calls for

new containment program. Science. 2004 May 28;304(5675):1223-5.