Middle East respiratory syndrome coronavirus (MERS-CoV)

Extract from the presentation byDr Benedict SimInfectious disease physicianHosp Sg Buloh4 July 2013

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Outline

• What will MERS-CoV look like?• Who has MERS-CoV?• Who to test?• How do test?• When and where to admit?• What infection control needed?• How to treat ?

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What will MERS-CoV look like?

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Pt characteristics (as of 7.6.13)

Male to female ratio 2.6 : 1.0 Median age 56 years (range: 2–94 years) All aged >24 years, except 2 children(2 & 14 yrs)

Deaths:

Case fatality rate = 31/55 = 56%

4~14d after onset, 2~10d after hospitalization

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Mortality 55%

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N Engl J Med 2013;368:2487-94.

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Important findings

Limited person-to-person transmission

Settings: Hospital, Household

Most family members and HCWs closely exposed did not develop disease

No evidence at present of sustained person-to-person transmission

Coinfection with influenza & parainfluenza - ? Roles in transmissibility and/or the severity of the illness.

Transmissibility pattern ? SARS

Reported case of milder nCoV illness – spectrum of clinical disease maybe wider

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This article was published on June 19, 2013, at NEJM.org8

23 confirmed cases in Eastern Saudi Arabia

• fever • cough • shortness of breath • gastrointestinal

symptoms • diarrhoea • vomiting• abnormal CXR

20/23 (87%) 20/23 (87%) 11/23 (48%)8/23 (35%)5/23 (22%) 4/23 (17%) 20/23

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Clinical symptoms• Most - pneumonia. Some - GI symptoms,

diarrhoea• 1 immuno-compromised patient - fever and

diarrhoea; pneumonia only on CXR • Half have died. • Complications

– respiratory failure – ARDS with multi-organ failure– renal failure requiring dialysis– consumptive coagulopathy – pericarditis

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Incubation period

• Where exposure is known or strongly suspected - generally < 1/52

• In at least one case, 9 to 12 days• In a minority of cases, may exceed

one week but is less than 2 weeks

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Route of transmission

Undetermined

Droplet and direct contact probably

Large droplet transmission is suspected as the most likely route.B Guery et al. Clinical features and viral diagnosis of two cases of infection with Middle East Respiratory Syndrome coronavirus: a report of nosocomial transmission. Lancet (2013).

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What we know• infections can occur across

the age range – most in older people with comorbids

• very high fatality rate• Sporadic cases in

communities• limited person to person

transmission – families & healthcare settings

• Some travel-related cases, but no big outbreaks

What we do not know

• How people in communities get infected?

• what is the main exposure?

• what are the main risk factors?

• what is the animal reservoir?

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Who has got MERS-CoV?

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WHO Interim case definition 3.7.13

Confirmed case• A person with laboratory

confirmation of MERS-CoV infection. – molecular diagnostics including either

+ve PCR on at least two specific genomic targets or a single +ve target with sequencing on a second.

Probable case

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WHO Interim case definition 3.7.13 Probable case

Febrile ARI Clinical, radiological/ HPE evidence (C/R/HPE) of pulm parenchymal ds (PPD)eg. pneumonia or ARDS

Testing for MERS-CoV

Contact history

unavailable / negative on a single inadequate specimen

Direct epid-link with a confirmed MERS-CoV case

Inconclusive MERS-CoV (+ve screening test w/out confirmation)

A resident of or traveler to Middle East 14/7 before onset of illness

Of any severityInconclusive MERS-CoV (+ve screening test w/out confirmation)

Direct epid-link with a confirmed MERS-CoV case

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1 Inadequate sp • NP swab without lower resp sp, • sp with improper handling, • judged to be poor quality by lab, • taken too late.

2 A direct epid link may include:• Close physical contact• Working together in close proximity or sharing the same

classroom environment• Traveling together in any kind of conveyance • Living in the same household• 14/7 period before or after the onset of illness in the case under

consideration.3 Inconclusive tests may include:

• A positive screening test without further confirmation eg positive on a single PCR target

• A serological assay positive.

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Inconclusive testing: 3.7.131. Should undergo additional virologic and

serologic testing.2. Strongly advised that lower resp sp such as

sputum, ET aspirate, or BAL be used. 3. If no S&S of LRTI and lower track sp not

available or clinically indicated, both NP and OP swab sp should be collected.

4. If NP swab is negative in a pt strongly suspected to have MERS-CoV infection, retest using a lower resp sp or a repeat NP sp with additional OP sp and paired acute and convalescent sera.

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Who to test?

MOH 14.6.13

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Patient Under Investigation (PUI)

• SARI, (include history of fever and cough) and indications of PPD (e.g., pneumonia or ARDS), based on clinical or radiological evidence of consolidation, (possibility of atypical presentations in immunocompromised) AND

• Travel to the Middle East 14/7 before AND

• Not explained by other aetiologySARI = severe acute respiratory illnessPPD = pulmonary parenchymal disease

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Contacts• ARI of any severity,

– 14 days before onset of illness– close physical contact with a confirmed

or probable case of MERS-CoV infection • HCW

– working where pt with SARI cared for, (esp ICU)

– without regard to history of travel (WRTHOT)

– Not explained by other aetiology

ARI = Acute respiratory illness

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Who to test?

WHO 27.6.13

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Who should be investigated?- summarized

• SARI + PPD + either– In a cluster (within 14/7)– HCW exposed to pt with severe LRTI– Traveled to middle east - 14/7– unexpected clinical course unexplained by

current aetiology • ARI of any severity

– close contact with confirmed/probable MERS-CoV within 14/7

• Middle East, any ventilated pt

SARI = severe acute respiratory illnessPPD = pulmonary parenchymal disease 24

SARI + PPD + either• cluster (>1 persons in a specific setting -classroom, workplace,

household, extended family, hospital, other residential institution, military

barracks or recreational camp) that occurs within 14-days, WRTHOT unless another aetiology identified (UAAI).

• HCW working with severe ARI patients (particularly ICU) WRTHOT UAAI

• travel to the Middle East within 14 days before onset of illness, UAAI.

• unusual or unexpected clinical course, especially sudden deterioration despite appropriate treatment, WRTHOT , even if another aetiology has been identified, if it does not fully explain the presentation or clinical course of the patient.

WRTHOT = without regard to history of travel 25

How to test?

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WHO 27 June 2013 update

• Stronger recommendations for lower respiratory specimens, rather than NP swabs, to be used to diagnose MERS-CoV infection.

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WHO 27.6.13

• NP swabs are not as sensitive as lower respiratory specimens – BAL, tracheal aspirate, sputum

• If patients do not have LRTI or specimens not possible, both NP and OP should be collected

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When to admit?Where to admit?

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Respiratory impairment: any of the followingTachypnoea, respiratory rate > 24/minInability to complete sentence in one breathUse of accessory muscles of respiration, supraclavicular recessionOxygen saturation < 92% on pulse oximetryDecreased effort tolerance since onset of ILIRespiratory exhaustionChest pains

Evidence of clinical dehydration or clinical shockSystolic BP < 90mmHg and/or diastolic BP < 60mmHgCapillary refill time > 2 seconds, reduced skin turgor

Altered Conscious level (esp. in extremes of age)New confusion, striking agitation or seizures

Other clinical concerns:Rapidly progressive (esp. high fever > 3 days) or serious atypical illnessSevere & persistent vomiting 30

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What infection control needed?

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Administrative controls

• Most important• From door to door• Infrastructures and equipment• Education of HCWs• Prevent overcrowding in waiting areas• Placement of hospitalized patients• Occupational health; seeking medical care• Monitoring of compliance. • Rapid identification of patients.

Triaging !

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Environmental and engineering controls

• Adequate ventilation• Regular environmental cleaning• Spatial separation of at least 1 m

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PPE

• Rational and consistent use of PPE and appropriate hand hygiene.

In this document, the term "medical mask" refers to disposable surgical or procedure masks.

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Isolation precautions

Standard precautions+

Droplet precautions +

Contact precautions

Airborne for aerosol generating proceedures

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How to treat ?

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No antiviral available !

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Early recognition and management

• Recognize SARI• Initiate infection control measures • Give supplemental O2 therapy • Collect respiratory and other sp for lab testing • Empiric antimicrobials for suspected pathogens• Conservative fluids when no shock• No high-dose steroids or other adjunctive

therapies outside the context of clinical trials• Watch for clinical deterioration, eg severe resp

distress/resp failure; tissue hypoperfusion/shock

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Thank you

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