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Professor David Koh MBBS, MSc, PhD, FFOM, FFOMI, FFPH, FAMS

Occupational Health Conference Muscat, 11-13 Dec 2006. Emerging Infections and Health Care Workers. Professor David Koh MBBS, MSc, PhD, FFOM, FFOMI, FFPH, FAMS Department of Community, Occupational and Family Medicine Faculty of Medicine.

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Professor David Koh MBBS, MSc, PhD, FFOM, FFOMI, FFPH, FAMS

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  1. Occupational Health Conference Muscat, 11-13 Dec 2006 Emerging Infections and Health Care Workers Professor David Koh MBBS, MSc, PhD, FFOM, FFOMI, FFPH, FAMS Department of Community, Occupational and Family Medicine Faculty of Medicine

  2. Emerging and Re-emerging Infectious Diseases, 1996 - 2001 SARS 2002-2003 Source: WHO, 2003

  3. SARS Probable cases of SARS worldwide, 7 August 2003. Source: WHO Cumulative Total : 8,422 cases and 916 deaths, reported from 29 countries

  4. SARS – an occupational health threat • 20 % of SARS patients were HCWs (n=1706) • Range: 19% in the China, 43% in Canada • 57% in Vietnam • 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.

  5. 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

  6. Attack Rates among HCWs in Hong Kong 339 SARS infected HCWs in 14 of 16 Hospital Authority hospitals that managed SARS cases (0% - 3.6, 4.4 %) Staff Category Attack Rate Range Nurses 1.21 % 0 – 4.7 % Medical / Technical 0.29 % 0 – 1.5 % * Non-medical support2.73 % 0 – 13.3 % Overall 1.2 % * Healthcare assistants, cleaners, clerical staff 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

  7. High risk procedures - Intubation, suction - Nebulized aerosol therapy - Positive pressure non-invasive ventilation

  8. The Inanimate Environment Can Facilitate Transmission Xrepresents VRE culture positive sites ~ 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.

  9. 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

  10. 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

  11. Study of SARS among HCWs in Singapore Objectives To study : - work and non-work related problems among health care workers in Singapore Study Design Questionnaire survey of 15,025 health care workers in 9 health care settings, from May-July 2003 D Koh, C Fones, MK Lim, SE Chia, F Qian, V Ng, S Emmanuel, NP Fong, G Koh, CT Kwa, BH Tan, KS Wong, W Ng, Z Muttakin, KB Tan, WM Chew, HK Tang, SM Ko. Impact of SARS on Health Care Workers in Singapore. Medical Care 2005 Jul;43(7):676-82.

  12. 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”

  13. 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”

  14. SARS – a newly emergent occupational disease * Health care workers * Animal and food preparation handlers * Transport workers - flight attendants, taxi drivers * Laboratory Researchers D Koh, Lim M-K, Ong C-N, Chia S-E. Occupational health response to SARS. Emerg Infect Dis [serial on the Internet]. 2005 Jan [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no01/04-0637.htm

  15. Will SARS Re-emerge ? • Most likely scenarios : • Original or new animal reservoir • Undetected transmission in humans (? Seasonal) • Persistent infection in humans • Laboratory accidents

  16. Post July 2003 cases of SARS 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.

  17. Guangdong, China Dec 2003 – Jan 2004 • 32 y/o male TV producer (rats in apartment) • 20 y/o restaurant waitress • , 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) 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

  18. 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.

  19. Are We Prepared ? Singaporean and Japanese Health Care Worker Perceptions, 2003 Singapore Japan n = 10,511 n = 7,282 % felt "At great risk of exposure to SARS"66% 64% % “Afraid of falling ill with SARS"76% 55% % felt that "Protective measures were effective" 96 % 31% % thought that "Protective measures were necessary and important"95 % 88% % felt that “Policies and protocols were clear”93% 65% % thought that “Policies and protocols were implemented"90 % 50% % felt that “Recommended measures were adhered to"92 % 43%

  20. Learning Point Initial infections of HCWs at the outset of an outbreak may sometimes be due to perceptions that recommended policies and measures are unnecessary or excessive.   …. efforts to educate and communicate the rationale and importance of protective measures may be especially important when outbreaks seem distant and perceived danger is low.   D Koh, K Takahashi, MK Lim, T Imai, SE Chia, F Qian, V Ng, C Fones. SARS risk perception and preventive measures, Singapore and Japan. Emerg Infect Dis [serial on the Internet]. 2005 Apr [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no04/04-0765.htm

  21. Influenza A Viruses H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H11 H12 H13 H14 H15 N1 N2 N3 N4 N5 N6 N7 N8 N9 Orthomyxovirus - with 8 segmented ssRNA genome Subtypes based on basis of two surface antigens: - Hemagglutinin (H) - Neuraminidase (N) H1N1, H3N2 and H1N2 affect humans and are globally circulated H5N1 - causes avian influenza Source: Nicholson, Wood and Zambon. Lancet 2003; 362: 1733-45.

  22. Why the Concern about H5N1 H5N1 strain mutates frequently H5N1 has the capacity to jump the species barrier to cause disease in humans (documented in 1997, 2003, 04, 05) H5N1 infection in humans has a high fatality rate Genetic mutation in the last few years show increasing H5N1 virulence and capacity to infect mammals ? Emergence of a new subtype of virus that can infect humans and be transmitted to other humans Linda Stannard, of the Dept of Medical Microbiology, University of Cape Town

  23. Hong Kong, SAR 1997 18 Human cases of H5 N1 influenza 9 were children < 10 yrs 7 mild disease 11 severe with pneumonia 6 fatalities (< 10 yrs, 1/9 ; > 12 yrs 5/9) * Close contacts with affected poultry Index case had contact with chickens and ducks in school 3 cases purchased poultry from market before illness 2 cases had live H5N1+ve chicken outlet near their home 5 cases had regular visits to markets/live chicken outlets 1 case worked in the market Tam JS. Influenza A (H5N1) in Hong Kong: an overview. Vaccine 20 (2002): S77-S81.

  24. 29 Dec 1997 – 15 Jan 1998 Serological survey of 293 government workers (cullers) and 1525 poultry workers Poultry Workers 10 % sero+ve for H5 (by microneutralization and Western blot assay) Risk factors: butchering poultry, exposure to poultry with >10% mortality Government Workers (Cullers) 3% were sero+ve for H5 229 (78%) had paired serum samples (2 wks later) 1 seroconverted (respiratory illness on 27 Dec) Bridges CB et al. Risk of Influenza A (H5N1) infection among poultry workers, Hong Kong, 1997-1998. J Infect Dis 2002; 185: 1005-10.

  25. H5N1 Transmission to Health Care Workers 217 exposed, 309 non-exposed HCWs studied Exposed and non-exposed HCWs reported no difference in poultry exposure 89% of exposed HCWs had paired serum samples 3.7% (8/217) of exposed HCWs were H5N1 sero+ve (2 of these exposed HCWs seroconverted) 0.7% (2/309) of non-exposed HCWs were H5N1 sero+ve Risk factors: Bathing patient, changing bed linen of patient From: BBC Bridges CB et al. Risk of influenza A (H5N1) infection among health care workers exposed to patients with influenza A (H5N1), Hong Kong. J Infect Dis 2000; 181:344-8.

  26. As at 29 Nov – 258 cases, 154 deaths http://gamapserver.who.int/mapLibrary/Files/Maps/Global_H5N1inHumanCUMULATIVE_FIMS_20061113(2).png

  27. H5N1 in Other Animals Haiyan L. I. & Chin J. Chinese J. Prev. Vet. Med., 26. 1 - 6 (Jan 2004) H5N1 virus found in 2003 in pigs in southeast China Haiyan L. I. & Chin J. Chinese J. Prev. Vet. Med., 24. 304 - 309 (May 2004) Reported similar results from pigs tested elsewhere in 2001 and 2003 H5N1 in CATS – leopards, tigers, domestic cats http://www.fao.org/ag/againfo/subjects/en/health/diseases-cards/avian_cats.html

  28. Report of probable person to person transmission of bird flu in Thailand • Index patient (Sep 2004) • 11 year old girl, who became ill a few • days after exposure to dying chickens • Mother (no history or poultry exposure) • travelled from distant city to provide • 16-18 hours of unprotected nursing care • Mother died from pneumonia – autopsy tissue +ve for H5N1 • Aunt also provided unprotected nursing, and developed fever and pneumonia • Nasopharyngeal & throat swabs +ve for H5N1 • K. Ungchusak et al. Probable person-to-person • transmission of avian influenza A (H5N1). • New Engl. J. Med, 2005: 352 333–340. 27 Jan 2005 Patient Mother Aunt

  29. SCIENCE Vol 308 No 5721 22 April 2005 Update on North Vietnam - 70 % mortality previously - 20 % mortality since Jan 2005 - Cases occur in larger clusters e.g. 5 members in one family - Previously among children, young adults, but now affects people of all ages - Disease appears to be less virulent and more infectious - Still ? no evidence of person-person transmission

  30. Influenza Pandemics in the Last Century 1918-19 Spanish Influenza H1 N1 30 million deaths 39 years later . . . 1957-58 Asian Influenza H2 N2 1 million deaths 11 years later . . . 1968-69 Hong Kong Influenza H3 N2 800,000 deaths 38 years later . . . winter 2006 ? ? ?

  31. Summary Several viral zoonotic diseases have recently emerged Occupational exposures are relevant in many cases Healthcare workers are at risk Illnesses are severe with mortality rates of 10%-75% These outbreaks recur - we should be alert & prepared

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