Occupational Health Conference Muscat 11 -13 Dec 2006

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

Emerging and Re-emerging Infectious Diseases, 1996 - 2001 SARS 20022003 Source: WHO, 2003

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

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.

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 (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 support 2. 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/vol 10 no 8/04 -0041. htm

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

The Inanimate Environment Can Facilitate Transmission X represents VRE culture positive sites ~ Contaminated surfaces increase cross-transmission ~ Abstract: The Risk of Hand Glove Contamination after Contact with a VRE (+) Patient Environment. Hayden M, ICAAC, 2001, Chicago, IL.

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 TS, 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/vol 10 no 2/030452. htm

The impact of SARS extends ond 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

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.

Impact on Family and Social life 82% were concerned about passing SARS to family close friends, colleagues 87% agreed that “people close are worried for my health” 69% felt that “people close to worried they might get me” members, or work to me are infected through

Impact on Family and Social life Negative 49% thought that “People because of my job” avoid me 31% felt that “people avoid my members because of my job” family Positive 82% of respondents felt the employer” “appreciated by 77% felt “appreciated by society”

SARS – a newly emergent occupational disease * Health care workers * Animal and food handlers * Transport workers flight attendants, taxi drivers preparation - * 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/vol 11 no 01/04 -0637. htm

Will SARS Re-emerge ? Most likely scenarios : 1 Original or new animal reservoir 2 Undetected transmission humans (? Seasonal) 3 Persistent infection in humans 4 Laboratory accidents in

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.

Guangdong, China Dec 2003 – Jan 2004 1 32 y/o male TV producer in apartment) 2 20 y/o restaurant waitress 3, 4 (rats 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/vol 10 no 10/04 -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.

Singaporean and Japanese Health Care Worker Perceptions, 2003 Are We Prepared ? Singapore n = 10, 511 % felt "At great risk of exposure SARS" 66% Japan n = 7, 282 to 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 clear” 93% % thought that “Policies and implemented" 90 % were 65% protocols were 50% % felt that “Recommended measures were adhered to" 92 % 43%

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/vol 11 no 04/04 -0765. htm

H 1 N 1 H 2 N 2 H 3 N 3 H 4 N 4 H 5 N 5 H 6 N 6 H 7 N 7 H 8 N 8 H 9 N 9 Influenza A Viruses H 10 H 11 H 12 H 13 H 14 H 15 Orthomyxovirus - with 8 segmented ss. RNA genome Subtypes based on basis of two surface antigens: - Hemagglutinin (H) - Neuraminidase (N) H 1 N 1, H 3 N 2 and H 1 N 2 affect humans and are globally circulated H 5 N 1 - causes avian influenza Source: Nicholson, Wood and Zambon. Lancet 2003; 362: 1733 -45.

Why the Concern about H 5 N 1 strain mutates frequently H 5 N 1 has the capacity to jump the species barrier to cause disease in humans (documented in 1997, 2003, 04, 05) H 5 N 1 infection in humans has a high fatality rate Linda Stannard, of the Dept of Medical Microbiology, University of Cape Town Genetic mutation in the last few years show increasing H 5 N 1 virulence and capacity to infect mammals ? Emergence of a new subtype of virus that can infect humans and be transmitted to other humans

Hong Kong, SAR 1997 18 Human cases of H 5 N 1 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 H 5 N 1+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 (H 5 N 1) in Hong Kong: an overview. Vaccine 20 (2002): S 77 -S 81.

29 Dec 1997 – 15 Jan 1998 Serological survey of 293 government workers (cullers) and 1525 poultry workers Poultry Workers 10 % sero+ve for H 5 (by microneutralization and Western blot assay) Risk factors: butchering poultry, exposure poultry with >10% mortality to Government Workers (Cullers) 3% were sero+ve for H 5 229 (78%) had paired serum samples (2 wks later) 1 seroconverted (respiratory illness on 27 Dec) Bridges CB et al. Risk of Influenza A (H 5 N 1) infection among poultry workers, Hong Kong, 1997 -1998. J Infect Dis 2002; 185: 1005 -10.

H 5 N 1 Transmission to Health Care Workers 217 exposed, 309 non-exposed HCWs studied Exposed and non-exposed HCWs difference in poultry exposure reported no 89% of exposed HCWs had paired serum samples 3. 7% (8/217) of exposed HCWs were H 5 N 1 sero+ve these exposed HCWs seroconverted) (2 of 0. 7% (2/309) of non-exposed HCWs were H 5 N 1 sero+ve Risk factors: patient, changing bed linen of patient Bathing From: BBC Bridges CB et al. Risk of influenza A (H 5 N 1) infection among health care workers exposed to patients with influenza A (H 5 N 1), Hong Kong. J Infect Dis 2000; 181: 344 -8.

As at 29 Nov – 258 cases, 154 deaths http: //gamapserver. who. int/map. Library/Files/Maps/Global_H 5 N 1 in. Human. CUMULATIVE_FIMS_20061113(2). png

H 5 N 1 in Other Animals Haiyan L. I. & Chin J. Chinese J. Prev. Vet. Med. , 26. 1 - 6 (Jan 2004) H 5 N 1 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 H 5 N 1 in CATS – leopards, tigers, domestic cats http: //www. fao. org/ag/againfo/subjects/en/health/diseases-cards/avian_cats. html

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 Patient Mother Aunt 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 H 5 N 1 Aunt also provided unprotected nursing, and developed fever and pneumonia Nasopharyngeal & throat swabs +ve for H 5 N 1 K. Ungchusak et al. Probable person-to-person transmission of avian influenza A (H 5 N 1). New Engl. J. Med, 2005: 352 333– 340. 27 Jan 2005

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 members in one family e. g. 5 - Previously among children, young adults, but now people of all ages affects - Disease appears to be less virulent and more infectious - Still ? no evidence of person-person transmission

Influenza Pandemics in the Last Century 1918 -19 Spanish Influenza H 1 N 1 30 million deaths H 2 N 2 1 million deaths 39 years later. . . 1957 -58 Asian Influenza 11 years later. . . 1968 -69 Hong Kong Influenza H 3 N 2 38 years later. . . winter 2006 ? ? ? 800, 000 deaths

Summary Several viral zoonotic diseases 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 have