Infection Prevention and Control for Filoviral Infections

Infection Prevention and Control for Filoviral Infections Professor Adriano G Duse Head: Division of Clinical Microbiology and Infectious Diseases & Director: Hospital Epidemiology & Infection Control Services

School of Pathology of the NHLS and University of the Witwatersrand, Johannesburg, South Africa

African viral hemorrhagic fevers

Viruses associated with haemorrhagic fevers fall into three groups with respect to their reservoir hosts and primary means of transmission, namely,

rodent-associated viruses

arthropod-borne viruses (arboviruses)

viruses thought to be associated with bats

Viral hemorrhagic fevers transmitted by

Mosquitos: e.g. Yellow Fever, Rift Valley Fever

Ticks: e.g. Crimean-Congo Fever

Rodents: Lassa Fever, Lujo Fever

Bat associated (?): Ebola & Marburg ‘Fevers’

Features common to VHF Notification: locally and in terms of IHR

Are zoonotic & most have high morbidity & mortality

Are caused by ssRNA viruses that are easily destroyed by agents such as bleach

They share similar pathogenetic mechanisms

For most: no commercially-available vaccine (except for YF, RVF), & no treatment (except for LF & CCHF); differential diagnosis huge!

=

Wide differential diagnosis!

VHFs are an uncommon cause of fever & bleeding: need to always maintain high index of suspicion; history-taking, including travel, is very important

Bacterial septicemia: streptococcal, staphylococcal, typhoid, gram-negatives (from

meningococci to bacilli – common e.g. S typhi to unusual e.g. Capnocytophaga),

Rickettsial infections: e.g. tick-bite fever

Spirochetal infections: e.g. leptospirosis

Parasitic infections: e.g. malaria

Other viral infections: HIV, fulminant hepatitis A & B, systemic herpesvirus infections, hemorrhagic Varicella zoster, hemorrhagic measles, etc.

Non-infective causes: neoplasia, drug sensitivities, anticoagulants, snake-bite, glue sniffing, traditional medicines, agricultural & industrial chemicals

Family: Filoviridae Single stranded RNA viruses (filum – Latin – thread)

Ebola West Africa 20(13)14 - 2016

Confirmed, probable and suspected EVD cases worldwide as at 28 February 2016. Total 28 603 cases (confirmed, probable, suspected) with 11 301 deaths(case fatality rate: 40%)

3804 2536

4809 10675

3956 14124

Ebola: Johannesburg 1996 SA 1996 (Crit Care Med, 2000;28(1):240-244

• 46 y old anesthetic assistant nurse (Index case)

significantly exposed to ‘imported’ Gabonese

primary/source & ‘atypical’ case: 29/10/96

• Acute febrile illness 02/11/96

• Series of events: delays in both diagnosis and

judgments – definitive diagnosis of Ebola v:

15/11/96

• Primary/source case traced to convalescent

home on 16/11/06 & confirmed to have had

Ebola Fever

• Cascades of actions and reactions, including

patient transfers & resulting in >1000 exposures

• Death of patient on 24/11/96 from intracranial

hemorrhage & nosocomial infectious

complications

Transmission

Transmission

• Direct contact with blood and bodily fluids (saliva, breast milk, vomitus, stool, tears, vaginal secretions, semen, etc.) during acute phase illness; convalescence: breast milk and semen

• No evidence of risk from casual skin contact with asymptomatic people

• Environmental contamination occurs but effectively mitigated by decontamination protocols

Infect Dis. 2007 Nov 15;196 Suppl 2: S142-7.Assessment of the risk of Ebola virus transmission from bodily fluids and fomites. Bausch DG, Towner JS, Dowell SF, Kaducu F, Lukwiya M, Sanchez A, Nichol ST, Ksiazek TG, Rollin PE.

Transmission, risk factors and infectiousness

• EBV ID is thought to be very low (1-10 virions)

• Risk factors

– hunting, slaughtering, butchering

– community and hospital care of EHF victims

– preparation of bodies and attending funerals (highest level of viremia at death)

–Viable viral persistence post mortem, non-human primate study: post-mortem viability in blood section: 7 days

–Detection of viral RNA in oral-nasal secretions & blood: up to 3 weeks

– In 1 study viability in liquid media, ambient temperature, > 40 days

Transmission, risk factors and infectiousness

• Ebola virus found in all sites & fluids associated with sexual activity; persistence in convalescence occurs in breast milk, rectum, vagina secretions & semen

– EV in breast milk of survivors > 16 months after onset of symptoms. Transmission risk unclear. Recent guidance: use of safe breast milk substitute until 2 consecutive negative EV tests obtained http://who.int/csr/resources/publications/ebola/guidance-survivors/en

• Pilot study involving 100 survivors at different times after EVD recovery:

Declining persistence of EV RNA persistence with increasing months since onset of EVD; however 11 of 43 (26%) of people had a positive specimen obtained 7-9 months after onset. Results of 1 participant who had specimen obtained at 10 months were indeterminate

Source: Deen et al NEJM 2015 Oct 14 [Epub ahead of print]

Infection rates

• The number of people that one sick person will infect, on average and in the absence of an effective control intervention, is called R0

• Estimated number of secondary cases generated by an index case in the absence of control interventions (R0) for Ebola in 2 epidemics 1.3 – 1.8

R0 More contagious

1 > 2 infection rate Hepatitis C Ebola (?)

1 > 4 infection rate HIV SARS

1 > 10 infection rate Mumps

1 > 18 infection rate Measles

Epidemiological characteristics of the 2014-16 West African Ebola outbreak

Summary of Ebola outbreak characteristics in West Africa

Term Definition Current estimates

Reproductive number (R0): Number of healthy people one sick individual infects over the course of his/her illness.

Guinea: 1.71 Liberia: 1.83 Sierra Leone: 2.02

Serial interval: Time between consecutive people falling ill in a chain of transmission.

15.3 days

Incubation period: Amount of time passed between a person becoming exposed to Ebola and when they start to show symptoms of the disease.

11.4 days

Doubling time: Time taken for the number of sick individuals to double. Guinea: 15.7 days Liberia: 23.6 days Sierra Leone: 30.2 days

Confirmed case fatality rate: Number of people who die of confirmed Ebola infection. Guinea: 70.7% Liberia: 72.3% Sierra Leone: 69.0%

Unconfirmed case fatality rate: Number of people who die of suspected but not confirmed Ebola infection.

Guinea: 13% Liberia: 58% Sierra Leone: 35%

Source: Doi:10.1371/journal.pntd.0003652.t002

EVD transmission: what is known and what is not …

• Limited data on how viral genomics affect phenotype/pathotype, patient VLs & epidemiological features of EBOV (Makona) strain

• Further study:

– Role of aerosol (large droplets/small particles close to patients) transmission

– Role on environmental contamination & fomite transmission

– Degree to which minimally or mildly ill persons transmit infection

– How long clinically relevant infection persists or persistence of Ebolavirus during convalescence

– Super-spreading events in transmission dynamics ?

– Whether strain differences or repeated serial passage in outbreak settings can impact virus transmission

Source: MBio 2015 Feb 19;6(2):e00137. doi:10.1128/mBio.00137-15

IPC: Health Worker Infections

Country Cases Deaths

Guinea 196 100

Liberia* 378 192

Sierra Leone 307 221 ‡

Total 881 513

* Data are until 9 May 2015 ‡ Data as of 17 February 2015

Ebola virus disease infections in healthcare workers in Guinea, Liberia and Sierra Leone as at 25 October 2015

World Health Organisation Ebola Situation Report 28 October 2015

Health worker Ebola infections in Guinea, Liberia and Sierra Leone


• Period: 1 January 2014 to 31 March 2015

• ‘Health worker’ very broad category; not just clinicians & nurses; also lab staff, drivers, cleaners, burial teams, janitors & community-based workers

– Depending on category, 21-32X more likely to be infected cf. general population

– Over this period, HCWs accounted for 3.9% (815/20955) of all confirmed & probable patients

– Nurses, nurse aids account for > 50% (373/718), followed by ‘medics’

• Difficulties in establishing where infections were contracted: at triage?;

community?; working in healthcare facilities in other centres, OPDs?; and homes?

WHO/EVD/SDS/REPORT/2015.1


Source: WHO/EVD/SDS/REPORT/2015.1

Determinants of health worker infections

• Deficiencies in administrative controls

– Lack of or inappropriate point of care risk assessment

– Problems with patient flows and zoning

– Lack of IPC policies and staff

– Lack of PPE supplies and training

• Lack of engineering and environmental controls

– Inadequate isolation and barriers

• Problems with PPE

• Defective practices/exposure at the point of care

– Transmission outside patient care setting

• Poor employment conditions and social determinants

Infection Prevention and Control (IPC)


• Main strategies: triage, early identification of cases, testing, isolation, supportive management; tracing and monitoring of contacts

• Nosocomial transmission amplification among HCWs

–Failure to strictly adhere to barrier precautions: contact with infectious blood, (other) tissues, excreta and other body fluids

–Sharps and splash injuries

–Mechanical aerosolization of infectious particles


• Administrative e.g.

– Formal protocols: screening, triage, all pertaining to IPC

– Restricted access; staff registers; OH&S

– IPC training, including donning & doffing of PPE

• Regular, structured trainings

• Behavioral modification – do not touch face (average touching of face 15.7 X per hour!)

• Selection and supply of PPE

• Have a trained donning & doffing instructor

– Laboratory and other support services

Infection Prevention and Control • Engineering / environmental e.g.

– Designated, physically separate donning and doffing areas from clinical care space

– Mostly unidirectional flow for patients & HCWs

– Placement of equipment

– Bed spacing

– Decontamination-friendly

IPC: Personal Protective Equipment (PPE)

Effectiveness of PPE for HCWs Caring for Patients with Filovirus Disease

• PPE recommendations & protocols differ across organizations responding to the outbreak, including WHO & MSF

– Different PPE item combinations & protocols confusing if no grounding in IPC

• In Oct 2014 WHO issued recommendations on PPE for use by HCWs managing patients with known or suspected filovirus disease

• Important is both effectiveness of PPE combinations in preventing EVD transmission as well as levels of dexterity & discomfort

• 30 observational studies of PPE of which 11 addressed filoviral disease; none compared different approaches to personal protection or different types of PPE

– Only 1 designed to evaluate PPE use

– All had reporting and/or methodological deficiencies; none addressed comfort & dexterity Source: PLOS ONE Ι DOI: 10.1371/journal.pone.0140290 October 9, 2015

Effectiveness of PPE for HCWs Caring for Patients with Filovirus Disease

• Conclusions:

• Insufficient evidence to draw conclusions on comparative effectiveness of different types of PPE & protocols; additional research urgently needed

• Future research in materials science & engineering: comfort, heat, breathability, visibility, minimization of viral contamination especially during doffing

• Other factors, not within scope of this review, e.g. hand washing & environmental cleaning are critical elements in IPC

Source: ONE Ι DOI: 10.1371/journal.pone.0140290 October 9, 2015

Other recent reviews: – Published : Fischer WA, et al. Clin Ther 2015; Nov 1;37(11): 2402-2410

• Review of articles pertaining to filovirus transmission in filovirus outbreaks & PPE donning & doffing studies

• All IPC pillars critical: administrative (including standard precautions) + environmental + PPE

• Current recommendations about PPE donning and doffing largely based on anecdotal evidence; however

– Discussion on role of PAPR vs. N95 respirators vs. surgical masks (latter effective)

– Face shields vs. goggles (no difference)

– Double gloving (decreased hand contamination during removal)

• General consensus: cover all skin and mucous membranes

• Instructed PPE donning doffing procedure important

• Thermal comfort & consideration of heat stress very important

• More studies with non-pathogenic bacteriophages, e.g. MS2, to inform the evidence

Other recent reviews: • Unpublished: Healthcare Workers Caring for Patients with Filovirus Disease: An Evidence-Based

Review on Personal Protective Equipment, WHO Advisory Committee IPC Task Force convened in early 2017

• Extensive literature search of articles from 1 Jan 1990 to 20 Apr 2018 to summarize (i) nosocomial filoviral transmission studies, (ii) effectiveness of PPE for HCW protection

– Of 353 studies, 36 evaluated effectiveness of PPE; 27 for EBV & 9 for SARS

– Overall quality of evidence for EBV; evidence about effectiveness of various PPE better for SARS

– Studies using surrogate viruses show; (i) positive impact of training, (ii) self-contamination occurs most often in participant’s inner glove

– Insufficient evidence to make conclusions about ideal PPE ensemble

• Basic IPC practices, PPE regularly reinforced training and stringent decontamination protocols

• Additional research needed to define optimal PPE outfit for use in subtropical climates

General principles 1

32

• VHFs are an uncommon cause of fever & bleeding: need to always maintain a high index of suspicion, especially in VHF outbreak situations

• Nosocomial (healthcare-associated) transmission and outbreak amplification among HCWs of most (except RVF) African VHF agents is well-described

– Failure to strictly adhere to standard (universal) precautions. Contact with infectious blood, (other) tissues, vomitus, excreta and other body fluids

– Sharps and splash injuries

– Mechanical aerosolization of infectious particles

• Regular training and re-training in IPC & the use of personal protective equipment (PPE) is very important

PPE training


34

• Previously listed VHF agents readily killed by simple disinfection:

– boiling (20-30 minutes),

– UV irradiation (sunlight),

– bleach, alcohol hand-rub

– soap and detergents!

• Survival, particularly in blood samples, dried blood and body fluids on medical devices & environmental surfaces is variable (days-weeks!)

• Important are:

– Decontamination of re-useable medical devices

– Safe disposal with restricted access to hazardous (infectious) waste


35

• Adhere to Standard Precautions at all times. When using enhanced (high-level) VHF PPE:

ENSURE THAT DONNING/REMOVAL OF PPE IS KEPT AS LOGICAL AND SIMPLE AS POSSIBLE!

• Limit Staff exposures

• (Ideally) dedicate senior, willing, and more experienced Staff

• Warn and educate all other relevant personnel involved in healthcare delivery. Do not forget other services (e.g. clinical, EMS, mortuary, etc.) personnel

RSA Concerns

36

– Unscheduled (unintentional) air evacuations

– Chartered flights

– Expatriates returning to SA who may have had a risk exposure

– Travelers (Foreign and National) from the affected W African regions via air, sea or land

36

• To date, few travelers diagnosed with viral hemorrhagic fevers ‘VHFs’ e.g. Lassa, Ebola, Marburg fevers) after long-distance travel

• No reports to date of VHF transmission to contacts during travel; however,

• Transmission has occurred in destination countries after travel if infection prevention and control precautions were not in place

Standard (Universal) Precautions

• Objective: reduce the risk of transmission of blood-borne and other pathogens from both recognized and unrecognized sources

• Key elements :

1. Hand hygiene

2. Risk assessment for appropriate PPE

3. Respiratory hygiene

4. Prevention of sharps & needle-stick injuries

5. Proper waste management

6. Environmental cleaning and disinfection to include patient-care equipment & environmental surfaces

38

Standard Precautions - PPE

SURGICAL MASK

SAFETY GLASSES

GLOVES

PLASTIC APRON

40

Standard Precautions PPE

1.Goggles

2.Respiratory Protective Equipment (RPE) – a surgical mask will suffice

4.Examination gloves

3.Apron

5.Surgical Scrubs Top and trousers

Do’s and Don’ts of wearing PPE

• DO:

– Change your gloves if they become torn or dirty; hand hygiene before putting on new gloves

– Wash your hands thoroughly with soap and water or an alcohol-based hand rub after removing PPE, including gloves. If hands are visibly dirty > use soap and water

– LIMIT the number of surfaces, items and people you touch while wearing PPE to prevent contamination

– Change any item of your PPE, or your own clothes, if it becomes contaminated

– If exposed to blood and body fluids or other potentially contaminated materials, stop working & immediately wash affected skin surfaces with soap and water; mucus membranes e.g. eyes: irrigate thoroughly with large amounts of clean water / eyewash solution. Document exposure as per the applicable OH&S company policy

• DON’T:

Touch your face or adjust your PPE with contaminated gloves

– Wash or reuse disposable gloves

41

VHF PPE

N95 RESPIRATOR

SURGICAL HOOD

INNER GLOVES

OUTER GLOVES

SAFETY GOGGLES

COVERALL

KNEE HIGH COVER SHOES

43

1. Scrub suit, rubber boots and put on (don) the first (inner) pair of disposable latex examination

gloves. Ensure that the scrub suit trouser legs are tucked into the rubber boots. If no gumboots

are available, knee-length cover (over) shoes used

2. Then, don the coverall. The head cover of the one-piece coverall not need to be worn if a hood is

available. If a hood is not available don the N95 respirator at this stage (see step 5 below) before

you cover your head with the head cover of the cove all. Ensure that the inner pair of gloves is

adequately tucked under the cuff of the sleeve of the coverall*

3. Then, put on either a disposable plastic or re-useable apron only if there is no protected, sealable

coverall zip

4. Next, don the second (outer) pair of disposable surgical gloves. These are longer than the

disposable latex gloves used as the inner pair enabling the outer pair to externally cover the cuffs

of the sleeves of the gown

PPE dressing-up (donning) procedure using a

coverall and a hood

PPE dressing-up (donning) procedure using a coverall

and a hood

44

5. Next, put on N95 Respirator and perform a fit-test to ensure that there is no leakage of air and that breathing is comfortable

6. Then, wear the goggles (or any other available equivalent) that will protect against eye and facial splashes.

7. If a hood is available, don it at this stage. If a hood is worn it is advisable that the disposable or reusable plastic apron mentioned in step 3 is donned after putting on the hood at this stage & not earlier

8. Then, wear the goggles (or any other available equivalent) that will protect against eye and facial splashes. These will be external to the hood.

9. Finally, check for any gaps and tears and ensure you are comfortable prior to entering a high-risk area

45

Step 1

Trousers tucked into Gumboots

Knee high Booties/Cover

Shoes

1st Pair of Gloves

Step 1 completed

46

Step 2

Ensure Gloves are adequately tucked under coverall sleeves

Practice point: Exposed skin not acceptable, gloves not

adequately tucked under sleeves

Step 2 Completed

Finger loop on Uvex coverall ensuring sleeve does not creep

47

Step 3

Ensure Apron is placed over hood

When tying apron at back make sure you to leave easy access

to untie the knot: butterfly knot with

easy-to-untie longer strap

Step 3 Completed

48

Step 4

Practice point: Visible exposed

skin under glove needs to be corrected

Outer gloves correctly covering the sleeve

49

Step 4 Continued

Finger loop seen through outer glove ,show good

position of sleeve relative to inner pair of gloves

Outer gloves taped in Clockwise direction

Be sure to create a lip for ease of access when

removing

50

Step 5

50

51

Step 5 Continued

Practice point: Respirator strap positioned uncomfortably over ear.

Expansion of Respirator on

exhalation

Retraction of Respirator on inhalation

52

Step 6,7,8

Don coverall hood and put goggles over hood

Adjust hood, goggles and respirator to ensure no skin is

exposed

Practise point : Ensure that sufficient amount of coverall hood is positioned under goggles to allow movement without exposing skin

53

Step 6,7,8 cont.

Surgical hood positioned to ensure that exposed

neck area is covered

Some models of coveralls are designed with a higher neck and cover flap to

protect the neck.

54

Step 9 Do final check of all PPE and adjust where necessary, ensuring that person is well protected and comfortable

PPE removal (doffing) procedure using a coverall with a

hood

55

1. On exiting the isolation area spray, using 0.5% chlorine/bleach solution*, the front, sides and back of the PPE wearer (avoid the face!) and then focus more specifically on the apron, gum boots, and outer pair of gloves

2. Next, carefully remove the apron and again disinfect* the gloved (inner pair of gloves) hands

3. Then, remove the outer pair of gloves and disinfect* the gloved (inner pair of gloves) hands

4. Now, carefully remove the goggles and again disinfect* the gloved (inner pair of gloves) hands

5. Next remove the coverall head cover / hood (if this available)

PPE removal (doffing) procedure using a coverall with a

hood

56

6. Then, remove the coverall carefully and again disinfect* the gloved (inner pair of gloves)

hands

7. Next, remove the N95 respirator and again disinfect* the gloved (inner pair of gloves)

hands

8. If you have completed your tasks for the day and will be dressing into your own clothes

remove the rubber boots or cover shoes / booties and again disinfect* the gloved (inner

pair of gloves) hands. If you intend to remain in a scrub suit to continue your duties in a

‘low risk’ area then the rubber boots are not removed

9. Then, remove the last inner pair of gloves and disinfect hands with a 0.05 %

chlorine/bleach solution

10. Finally move back into the low risk area

57

Doffing Step 1 Using a 0.5% solution of chlorine, decontaminate outer pair of gloves. Can be done either by washing hands in bowl containing the solution (preferable to avoid spray aersols) or “buddy” can gently spray hands using a spray bottle.

Remove tape in counter clockwise direction and again disinfect hands.

1 2 3

4 5 6

58

Step 2

59

Step 3

1.Buddy assist by releasing apron top

2.Let apron fold over it self, grasping only the inside edge

Apron inside out, folded over

3.Buddy assists releasing back tie.

4.Grasping only the straps or inside edge of apron, fold inside out as

illustrated

5.Dispose in healthcare waste box and disinfect

hands

60

Step 4

1.Buddy assists in releasing tie

2.Grasping on edge of strap pull hood inside out whilst tilting the head down and out.

3.Hood now inside out pulled away from head

4.Dispose in Healthcare waste box 5.Disinfect hands

61

Step 5

1.Clasp side edge of goggles 2.Pull goggles away from face 3.Dip head down and out while holding goggles is

same position

4.Once strap has slid over head move goggles straight

away from face

5.Re-usable goggles can be put in 0.5% chlorine

solution 6.Disinfect hands

62

Step 6

1.Open zip protection flap by moving only one hand on the inside of the material and work

your way down slowly

2.With guidance of buddy find zipper and while keeping

tension on zip , start unzipping in one steady movement

3.Disinfect hands

Practice point: Care has to be taken not to touch exposed skin of

neck

63

Step 7

Grasp hood with both hands, lift hood high over head and let it fall back away from

head and neck. A mirror is advantageous or buddy could assist

Practice point:Incorrect

position of hood touching exposed skin of neck and head

Good position of hood away from neck and

head

Step 8 Buddy assists by moving hands on inside of coverall

peeling open and over shoulders and then

pulling coverall down until person can assist them self. Let coverall

hang of sides

Peel coverall off inside out and

always only touching inside

of suit

Step 8 Cont.

Work the coverall inside out until the booties/boots are

visible

Create a generous lip with the booties over the coverall

Work the coverall inside out until foot can be released and step out

away from suit

66

Step 8 cont.

Follow same steps to release 2nd foot, again step away from suit

Coverall/booties completely turned inside out, bunch together and place

inside healthcare waste box.

67

Step 9

1.Grasp and hold side edges of respirator

2.Buddy assists by releasing top and bottom straps

3.Push respirator straight away from face and place in healthcare waste box

68

Step 10

Finally follow illustrated step to remove inner pair of gloves

Discard gloves in healthcare waste box and disinfect hands with 0.05% solution of chlorine

VHF PPE

THANK YOU

Infection Prevention and Control for Filoviral Infections

Documents

Transcript of Infection Prevention and Control for Filoviral Infections